

        <cite>Conor</cite>
      <time>0:00</time>
      <p>
          J,   APL,   the   array   languages,   they&#39;re   coming   to   C.   This   is   the   this   is   the   first.   Welcome   to   ADSP   the   podcast   episode   42,   recorded   on   September   1st,   2021.   My   name   is   Connor,   and   today   with   my   co-host   Bryce,   we   start   off   by   responding   to   some   tweets,   talk   about   working   remotely,   and   then   talk   about   inverse   scans   and   inverse   iota.   But   so   this   means   that   this   is   episode   42,   pretty   special   episode.   We   should   start   off   by   reading   some   tweets   because   we&#39;ve   got   we&#39;ve   gotten   a   lot   of   tweets.
      </p>

        <cite>Bryce</cite>
      <time>0:45</time>
      <p>
          Why   is   it   a   pretty   special   episode?
      </p>

        <cite>Conor</cite>
      <time>0:47</time>
      <p>
          Episode   42.   Come   on,   man.
      </p>

        <cite>Bryce</cite>
      <time>0:49</time>
      <p>
          Okay.
      </p>

        <cite>Conor</cite>
      <time>0:50</time>
      <p>
          You   don&#39;t   know   the   significance.   You   know   the   significance.
      </p>

        <cite>Bryce</cite>
      <time>0:54</time>
      <p>
          I   get   the   reference.   I   was   just   I   was   just   not   sure   if   that&#39;s   the   direction   you   were   going.   But   okay.
      </p>

        <cite>Conor</cite>
      <time>1:00</time>
      <p>
          Wow,   come   on,   man.   Uh   you   gotta   you   gotta   trade   some   of   that   decorator   knowledge   for   like   nerd   swag.   Uh   um   you   also   gotta   sit   a   little   closer   to   your   mic.   You   sound   like   you&#39;re   in   like   the   Notre   Dame.
      </p>

        <cite>Bryce</cite>
      <time>1:13</time>
      <p>
          I   I   think   that&#39;s   just   my   my   ceilings   are   very   like   I   don&#39;t   know   that   that&#39;s   gonna   get   better.
      </p>

        <cite>Conor</cite>
      <time>1:20</time>
      <p>
          Alright,   so   feedback   from   feedback   from   listeners.   We&#39;re   reading   feedback   because   there&#39;s   primarily   one   thing   I   want   to   read   out,   but   we&#39;ll   read   out   a   bunch   of   things.   So   a   few   episodes   ago,   we   were   talking   about   creating   a   new   acronym   based   on   C   companies   because   NVIDIA   is   not   in   the   FAIN   uh   acronym.
      </p>

        <cite>Bryce</cite>
      <time>1:38</time>
      <p>
          So   we   were   talking   about   That&#39;s   not   the   only   reason   that   we   dislike   FAIN.   We   were   also   like   We   don&#39;t   dislike   FAIN.   I   I   dislike   FAIN.   I   don&#39;t   like   that   like   I   feel   like   like   it   wasn&#39;t   about   NVIDIA.   I   was   like,   why   is   Netflix   on   there,   but   Microsoft   isn&#39;t?   But   yeah,   no   offense   to   people   who   work   in   Netflix,   but   I   don&#39;t   understand   why   you&#39;re   why   you&#39;re   classified   in   the   same   league   as   those   other   companies.   And   and   I   guess   like   part   of   it   is   a   number   of   those   companies   in   Fang   are   platform   companies,   you   know,   like   good   Google   and   Apple   both   have   like   this   huge   developer   ecosystem   around   them.   That&#39;s   not   the   case   for   Netflix.   It   is   the   case   for   Microsoft.   Um,   so   I   I   just   sort   of   find   it   well,   and   and   I   think   also   like   you   know,   in   many   ways   it   is   the   case   for   Facebook   too.   There&#39;s   an   ecosystem   around   Facebook.   Um,   but   like   Netflix   is   a   different   type   of   tech   company   um   and   a   different   type   of   tech   giant.   And   so   I   think   that   it&#39;s   a   little   bit   out   of   place   for   for   it   to   be   in   that   group.   It&#39;s   like   no   offense   to   Netflix.   Like,   it&#39;s   a   great   company,   obviously   it   you   know,   produces   a   great   product.   Um,   I   think   it&#39;s   a   really   cool   place   to   work.   Um   But   I   think   it&#39;s   um   I   think   it&#39;s   a   different   type   of   tech   company   than   the   rest.
      </p>

        <cite>Conor</cite>
      <time>2:59</time>
      <p>
          But   anyways,   I   agree.   I   th   I   would   I   would   venture   a   guess   if   you   had   to   name   like   the   top   five.   Well,   I&#39;m   not   wanting   to   say   paying,   like   salary   paying   slash   like   employing   like   large   employers   of   developers,   that&#39;s   not   like   niche,   like   you   know,   so   like   ignore   Wall   Street   because   obviously   they   pay   a   ton   to   devs.   Like   the   first   ones   that   come   to   mind   are   like   Apple,   Amazon,   Facebook,   Google,   and   then   like   Netflix   is   known   for   uh   paying   ridiculously   well.   Like   their   whole   thing   is   that   you   don&#39;t   even   really   need   to   you   don&#39;t   even   really   need   to   like   salary   negotiate.   They   do   a   ton   of   like   industry   research   on   what   top   dollar   is   for   their   position,   and   then   they   pay   that   to   you   almost   entirely   in   base   compensation.   Like   they   don&#39;t   really   have   like   a   variable   component   because   their   philosophy   is   if   you   no   longer   like   working   there,   they   don&#39;t   want   you   sticking   around   because   you&#39;ve   got   like   RSU&#39;s   ving,   which   is   like   the   complete   opposite   of   like   Amazon,   which   is   their   vesting   schedule   is   like   515   4040,   which   means   80%   of   their   RSUs   are   paid   out   two   years   in   the   last   two   years   of   like   a   four-year   stint.
      </p>

        <cite>Bryce</cite>
      <time>4:11</time>
      <p>
          But   but   like   like   out   of   the   that   list   of   like   well-known   companies   that   like   pay   well   that   you   just   listed,   I   think   it&#39;s   it&#39;s   really   hard   to   make   that   list   and   not   include   Microsoft.   Like,   like,   look,   I   I   understand   you   don&#39;t   include   NVIDIA   in   that   list   because   we&#39;re   not   in   the   same   class   as   those   companies,   but   I   think   it&#39;s   really   hard   to   talk   about   Apple,   Google,   Facebook,   and   not   also   talk   about   Microsoft.
      </p>

        <cite>Conor</cite>
      <time>4:35</time>
      <p>
          Yeah,   that&#39;s   true.   I   guess   that   it&#39;s   so   it&#39;s   a   bit   of   you   can   make   the   argument   for   Netflix   and   then   backronym   it,   right?   Because   you   had   AAFG,   and   if   you   add   M,   I   think   we   already   talked   about   this.   What   do   you   get?   You   get   you   get   GAMFA   or   something   like   that.   Yeah.   Whereas   if   you   if   you   if   you   What   did   this   listener   have   to   say?   Oh,   so   so   we   had   said,   let&#39;s   create   our   own   acronym.   Uh   we   were   talking   to   Sean,   so   it   was   Adobe,   Netflix.   You   wanted   to   include   Microsoft   because   they   were   left   out   of   the   Fang.   Yeah.   And   so   we   and   so   we   said,   well,   what   word   could   we   go   for?   And   I   mentioned   Maine,   if   we   could   find   an   I,   a   company   that   started   with   I.   And   so   we   had   a   we   had   uh   if   I   apologize   if   I   mispronounce   any   of   these   names,   I   I   uh   profusely   apologize.   But   Mahir   uh   Vadya   said,   uh,   which   company   starts   with   I?   Inner   voice   intel.   Inner   voice   intel   voice.   Okay,   we   will   let   the   listeners   tell   if   any   company   starts   with   I.   Uh   funny   that   neither   of   us   thought   of   Intel   considering.
      </p>

        <cite>Bryce</cite>
      <time>5:33</time>
      <p>
          Well,   I   thought   of   Intel,   but   um   I   think   we   I   think   I   thought   we   said   Intel.
      </p>

        <cite>Conor</cite>
      <time>5:37</time>
      <p>
          We   did   not.   We   can   we   couldn&#39;t   come   up   with   we   could   not   come   up   with   a   company   that   started   with   I,   so   my   question   is   is   do   I   have   to   cut   this   whole   part   out   of   the   episode?
      </p>

        <cite>Bryce</cite>
      <time>5:46</time>
      <p>
          Oh,   because   we&#39;re   not   supposed   to   promote   Intel?   Um   Well,   no,   they&#39;re   not   really   our   rivals.   We&#39;re   in   a   class   bar   on.   Um,   no,   I   like   it.   I   like   it.   Main   Microsoft,   Adobe,   Intel,   Netflix.
      </p>

        <cite>Conor</cite>
      <time>6:02</time>
      <p>
          Netflix,   NVIDIA.
      </p>

        <cite>Bryce</cite>
      <time>6:08</time>
      <p>
          Oh   I   I   would   claim   jet   lag,   but   uh   that&#39;s   probably   not   gonna   hold   up.
      </p>

        <cite>Conor</cite>
      <time>6:12</time>
      <p>
          I   mean,   uh   Eric   uh   Eric   Keane,   right?   He   works   at   Intel.   He&#39;s   a   he&#39;s   a   class   act.   I   love   uh   he&#39;s   really   great.   Yeah,   and   uh   and   Jeff   Hammond,   he   just   came   from   Intel,   and   he&#39;s   a   super   nice   guy.   So   the   of   the   people   that   I   know   that   have   come   from   or   are   at   Intel,   they&#39;re   they&#39;re   lovely   people.
      </p>

        <cite>Bryce</cite>
      <time>6:28</time>
      <p>
          So   yeah.   Yeah,   yeah.   No,   and   I   mean   Intel&#39;s   Intel&#39;s   a   cool   sh   like   and   you   know,   one   of   the   interesting   things   about   that   acronym   is   it   doesn&#39;t   name   all   of   the   big   C   orgs,   but   it   gets   most   of   them.   Um   Intel&#39;s   big   and   invested   in   C.   Uh,   so   is   Adobe.   It&#39;s   a   classic   C   shop,   and   so   does   NVIDIA.
      </p>

        <cite>Conor</cite>
      <time>6:57</time>
      <p>
          Outside   of   the   Fang   companies   that   also   are,   what   would   you   name?   Bloom   Bloomberg,   obviously.
      </p>

        <cite>Bryce</cite>
      <time>7:02</time>
      <p>
          Yeah,   yeah,   we   would   have   to   work   Bloomberg   in.
      </p>

        <cite>Conor</cite>
      <time>7:04</time>
      <p>
          Do   we   have   to   work   Bloomberg   again?
      </p>

        <cite>Bryce</cite>
      <time>7:05</time>
      <p>
          All   right,   so   do   we   need   a   new   Yeah,   because   Bloom   Bloomberg,   Bloomberg   is   one   of   the   um   Bloomberg   is   one   of   the   largest   investors   in   the   C   ⁇   community.   Yeah.   Um   it&#39;s   one   thing   that   you   know   Bloomberg   does   a   real   like   if   you   look   at   if   you   look   at   um   financial   tech   companies   of   which   Bloomberg   is   it   it   would   be   wrong   to   classify   Bloomberg   as   like   an   HFT   company   because   that&#39;s   not   what   they   do.   They&#39;re   they&#39;re   not   an   HFT   firm,   but   they   they   provide,   you   know,   these   um   uh   it&#39;s   almost   like   market   services,   you   know,   data   information,   you   know,   the   the   the   this   stream   of   information   about   various   markets.   Um   so   like   in   some   ways   they&#39;re   sort   of   like   a   news,   you   know,   or   but   they&#39;re   definitely   like,   you   know,   I   think   they   fall   under   the   guise   of   financial   tech.   But   um   there   are   a   few   others   that   invest   in   the   C   community,   like   Citadel,   but   by   far   the   most   present   one   is   Bloomberg.   I   I   learned   I   learned   something   interesting   about   Bloomberg.   Um,   because   I   was   having   dinner   with   with   one   of   my   colleagues,   Alistair,   who   works   at   Bloomberg,   and   he   told   me   that   at   Bloomberg,   they&#39;ve   got   so   so   they&#39;re   based   in   Manhattan.   Um,   and   until   a   few   years   ago,   they   they   were   they   didn&#39;t   like   remote   work   because   they   felt   that   you   you   lost   something,   um,   you   lost   some   element   of   collaboration   by   not   having   everybody   local.   But   they   did   this   other   thing,   which   is   very   interesting,   which   is   they&#39;ve   got   three   or   four   different   sites   within   the   city.   And   every   few   years,   you   get   moved   your   your   team   and   your   org   moves   where   your   office   space   is.   Maybe   within   the   same   building,   but   also   maybe,   you   know,   maybe   you   move   from   one   of   the   offices   in   Manhattan   to   a   different   office.   And   this   consistently   happens   every   few   years,   that   everybody   gets   moved.   And   it&#39;s   like   important   to   them   that   everybody   gets   moved   so   that   you   don&#39;t   get   used   to   being   in   one   place.   Um,   and   the   idea   is   that   like   you   move   around,   you   you   move   around   where   all   the   different   teams   are   to   so   that   every   few   years,   hey,   you&#39;re   sitting   next   to   a   new   group   of   people   and   you   get   exposed   to   a   different   part   of   the   company.   Um,   and   then   that   way,   like,   there&#39;s   more   chances   for   synergy.   Um,   and   that   it&#39;s   something   that   becomes   a   regular   part   of   the   culture.   So,   so   once   like   if   you   if   your   desk   is   going   to   be   moved   every   year,   you   know,   one,   the   company   gets   used   to   doing   these   moves,   and   two,   you,   the   employee,   get   used   to   it,   so   it&#39;s   not   a   big   hassle.   So   I   just   thought   that   was   interesting.
      </p>

        <cite>Conor</cite>
      <time>9:48</time>
      <p>
          Yeah,   that   is   interesting.   I&#39;ve   never   heard   of   anything   like   that.   Um   other   than   sort   of   like   open   office   or   open   concept   where   you   don&#39;t   really   have   a   desk   and   you   just   float   around.   Yeah,   like   I   think   that&#39;s   slightly   different.
      </p>

        <cite>Bryce</cite>
      <time>9:59</time>
      <p>
          I   think   Valve   does   that.
      </p>

        <cite>Conor</cite>
      <time>10:01</time>
      <p>
          Yeah,   I   was   at   an   insurance   company   before   I   was   a   dev   that   ended   up   doing   that.
      </p>

        <cite>Bryce</cite>
      <time>10:08</time>
      <p>
          Really?   But   let   when   you   think   of   like   innovative   um   uh   office   seating   practices,   you   don&#39;t   think   of   insurance   companies.
      </p>

        <cite>Conor</cite>
      <time>10:18</time>
      <p>
          Yeah,   I   mean   the   company   that   I&#39;m   I   was   referring   to   as   Manulife,   and   they   um   they   tried   to   they&#39;re   trying   to   be   they   they   developed   this   was   after   I   left,   but   I   heard   that   they   set   up   a   team   called   Loft,   which   stood   for   the   Laboratory   of   Forward   Thinking,   where   the   where   where   they   were   trying   to   generate   these   really   unique,   you   know,   insurance   ideas   and   policies.   So   like   I   think   I&#39;m   not   sure   if   it   was   out   of   ManuLife   where   they   copied   another   company,   but   I   definitely   know   that   there&#39;s   a   policy   in   Canada   through   Manulife   that   you   can   get   where   you   wear   a   Fitbit   and   it   keeps   track.   It&#39;s   like   a   an   insurance   company   issued   Fitbit   and   it   keeps   track   of   like   how   active   you   are,   and   you   can   get   like   a   reduced   premium   by   doing   exercise.   Um   and   also   there&#39;s   similar   things   for   car   insurance   in   Canada   where   you   can   get   like   little   brake   measurements   to   see   like   how   much   you&#39;re   braking   and   and   you   know,   sort   of   like   how   safe   you&#39;re   driving   and   whatnot,   and   that   affects   your   insurance   premiums   for   for   vehicle   insurance.   So   there&#39;s   some   neat   ideas.
      </p>

        <cite>Bryce</cite>
      <time>11:17</time>
      <p>
          This   is   a   thing,   this   is   a   thing   that   um   that&#39;s   not   as   common   these   days,   but   I   I   actually   I   was   reminded   of   this   because   I   was   watching   an   episode   of   uh   the   TV   show   Mad   Men.   Uh   I&#39;ve   been   watching   a   bunch   of   New   York-based   TV   shows   to   get   myself   in   the   in   the   New   York   mood.   And   uh,   and   also   if   we&#39;re   being   honest,   uh   uh   Mad   Men   has   a   lot,   a   lot   of   the   furniture   in   Mad   Men   is   mid-century   modern   style,   which   is   the   style   that   I   prefer.   So   I&#39;ve   been   watching   TV   shows   looking   for   looking   for   decorator   ideas.   But   um   uh   there&#39;s   there&#39;s   one   episode   where   one   of   the   main   characters   is   going   to   get   his   physical,   and   the   doctor   says,   oh,   like,   you   know,   you&#39;re   you&#39;re   only   in   here   because   your   insurance   company   is   requiring   it.   Um   and   this   like   used   to   be   a   thing   where   like   for   your   life   insurance   or   your   health   insurance,   your   your   insurance-   and   maybe   it   still   is,   but   maybe   it&#39;s   just   that   people   of   our   age   don&#39;t   have   that   requirement.   But   it   you   it   might   have   used   to   be   back   in   the   day   that   your   insurance   company   would   require   you   to   go   get   a   physical   every   few   years   and   then   you   know   send   them   the   results,   presumably.   I   think   today   people   would   think   of   that   as   an   invasion   of   their   privacy.   But   I   mean,   maybe   it&#39;s   still   a   thing.   Who   knows?
      </p>

        <cite>Conor</cite>
      <time>12:29</time>
      <p>
          Uh   I   think   definitely   it   is   for   certain   policies.   You   have   to   be   quote   unquote   underwritten.   Yeah.
      </p>

        <cite>Bryce</cite>
      <time>12:35</time>
      <p>
          Well   well,   so   let   me   let   me   ask   you   this.   So   you   um   when   did   you   move   back   to   Canada?
      </p>

        <cite>Conor</cite>
      <time>12:40</time>
      <p>
          Uh   2019.
      </p>

        <cite>Bryce</cite>
      <time>12:42</time>
      <p>
          Before   pre-pandemic,   of   course.
      </p>

        <cite>Conor</cite>
      <time>12:44</time>
      <p>
          Yeah,   just   a   few   months   before   the   pandemic,   yeah.
      </p>

        <cite>Bryce</cite>
      <time>12:46</time>
      <p>
          Do   you   think   um   and   and   you   were   on   a   team   that   was   a   remote   that   that   was   a   remote   first   team,   by   which   I   mean   it   was   a   team   that   was   remote   even   before   the   pandemic.
      </p>

        <cite>Conor</cite>
      <time>12:55</time>
      <p>
          Yep.
      </p>

        <cite>Bryce</cite>
      <time>12:56</time>
      <p>
          The   Rapids   team   at   Nvidia.   You   think   you&#39;d   ever   want   to   go   back   to   working   in   an   office?
      </p>

        <cite>Conor</cite>
      <time>13:02</time>
      <p>
          Uh   so   the   answer   to   that   question   is   if   I   have   to   choose   100%   remote   or   a   hundred   percent   in   the   office,   I   will   always   choose   remote.   The   flexibility   that   you   get   and   the   time   that   you   save   from   like   not   having   to   commute,   I   think   it&#39;s   it   outweighs   the   benefits   of   being   in   the   office.   I   definitely   miss   being   around   people,   uh,   like   especially   COVID   times.   I   essentially   live   by   myself   and   I&#39;m   just   isolated,   except   for   when   I   socialize,   which   isn&#39;t   often   because   it&#39;s   still   sort   of   pandemic-y.   And   uh   so   yeah,   like   if   I   had   it   my   way,   like   there&#39;s   an   NVIDIA   office,   and   I   would   probably   go   into   the   office   for   like   two   half   days   of   a   week   when   I   had   like   meetings,   and   I   just   take   my   laptop   with   me.   I   wouldn&#39;t   have   a   desk   and   I   just   sort   of   there&#39;s   a   a   space   in   the   sort   of   like   kitchen   area   where   you   can   you   can   grab   a   place   by   a   window   and   so   you   get   to   see   people,   you   get   to   whatever   chat   a   bit.   Um,   because   I   definitely   miss   that   like   water   cooler   aspect.   Like   it&#39;s   sort   of   hard   to   replicate   that,   especially   when   I&#39;ve   only   met   like   four   or   five   of   the   people   that   I   work   with   in   person.
      </p>

        <cite>Bryce</cite>
      <time>14:09</time>
      <p>
          Yeah.
      </p>

        <cite>Conor</cite>
      <time>14:09</time>
      <p>
          But   yeah,   the   convenience   of   like   being   able   to   make   a   sandwich   or   you   know   go   for   a   quick   run   in   the   middle   of   the   day.   Like   when   you&#39;re   at   work,   the   overhead   of   going   to   the   gym   or   going   for   a   run   where   you   have   to,   you   know,   then   shower   and   bring   extra   clothes   and   blah   blah   blah   and   all   this   stuff,   it&#39;s   just   just   a   headache.   Um   uh   yeah.
      </p>

        <cite>Bryce</cite>
      <time>14:32</time>
      <p>
          See,   it&#39;s   interesting   that   that   you   say   that   that   you   would   go   in   for   meetings   because   pre-pandemic,   the   days   that   I   had   all   meetings   might   would   the   days   that   I   like   wanted   to   stay   at   home,   because   uh   at   the   NVIDIA   headquarters   is   like   an   open   office   plan.   I   can&#39;t   have   my   meetings,   I   can&#39;t   take   my   meetings   from   from   my   desk.   Well   there   is   a   tolerance   to   how   many   meetings   I   could   take   from   my   desk   before   I   would   get   you   know   glares   from   my   coworkers   and   would   need   to   go   get   a   you   know   a   meeting   room.   So   those   are   the   days   that   I   would   almost   prefer   to   be   at   at   um   at   uh   at   home.   Um   and   like   I   I   used   to   think,   because   I   was   a   big   believer   in   like,   you   know,   uh   that   it   was   important   to   separate   your   work   space   from   your   living   space   for   like   work-life   balance,   um,   because   like   I   could   I   have   a   tendency   towards   being   a   workaholic,   so   I   thought   I   used   to   not   have   a   desk   at   home.   Um   I   used   to   try   to   never   have   a   workspace   at   home   so   that   I   would   have   to   go   into   the   office   when   I   wanted   to   work.   Like   I   did   that   when   I   was   at   Lawrence   Berkeley   Lab.   Um   I   I   uh   I   well   also   when   I   was   at   Lawrence   Berkeley   Lab,   I   lived   in   this   miserable   little   apartment   that   had   like   no   AC   and   no   ventilation.   So   you   didn&#39;t   want   to   be   in   there   during   the   day,   anyways.   Um   uh   but   uh   I   I   uh   at   this   and   same   thing   when   I   was   in   Santa   Clara,   when   I   was   at   NVIDIA   headquarters,   I   was   I   I   lived   in   a   smaller   apartment   that   didn&#39;t   have   space   for   a   home   office   or   a   desk   that   was   really   near   headquarters,   with   the   thinking   being,   okay,   if   I   want   to   work,   I&#39;ll   drive   five   minutes   into   the   office,   and   then   a   home   space   is   the   home   space.   And   then   at   the   start   of   the   pandemic,   I   was   like,   well,   I&#39;ll   have   to   find   the   I&#39;ll   have   to   figure   out   how   I   can   fit   a   small   desk   into   this   tiny   apartment.   Um   but   I   don&#39;t   think   I   would   go   back   because   no   matter   how   short   your   commute   is,   um   at   least   for   me,   and   I&#39;m   somebody   who&#39;s   you   know   had   ADD   my   whole   life,   the   the   fact   that   I   had   to   get   up,   put   on   clothes,   you   know,   pack   a   bag   of   all   the   stuff   I   would   need   for   the   day,   you   know,   eat   a   meal,   get   in   a   car,   and   drive   any   amount   of   distance,   like   those   series   of   actions   were   a   barrier   for   me   to   start   working.   Um   and   uh   it   was   also   a   barrier   for   me   to   stop   working.   And   that   was   actually   the   more   problematic   part.   That   if   I   was   at   the   office   and   I   was   sort   of   like   at   the   end   of   my,   you   know,   I&#39;d   run   out   of   energy,   but   I   like   wasn&#39;t   finished   with   my   task,   um   I   couldn&#39;t   decide   to   just   go,   you   know   what,   I&#39;m   gonna   have   dinner   now,   maybe   I&#39;ll   come   back   to   this,   you   know,   for   30   minutes   after   dinner.   Or,   you   know   what,   I&#39;m   just   I&#39;m   just   gonna   go   take   a   lunch,   or   I&#39;m   gonna   go   watch,   you   know,   something   on   Netflix   for   an   hour.   Now   I   could   do   that   middle   thing   of   like   I   could   go   like,   you   know,   just   sit   at   my   desk   and   watch   a   video   on   YouTube   at   the   office.   Um   but   making   that   decision   to   return   to   the   to   the   living   space   was   a   thing   that   I   would   do   once   during   the   day.   So   it   was   like   a   big   decision.   It   was   like   once   I   decided   I&#39;m   going   to   go   home   and   be   at   home   for   some   period   of   time,   then   I   have   stopped   working   for   the   rest   of   the   day.   And   for   me,   like   the   greatest   thing   about   being   working   at   home   is   that   I   can   choose   when   I   make   those   transitions.   Um   and   it&#39;s   not   a   commitment.   So   that   makes   it   easier   for   me   to   start   working   and   easier   for   me   to   stop   working.   And   I   think   that   that&#39;s   actually   led   to   me   to   have   a   better   work-life   balance   than   I   previously   had.   Um,   you   know,   if   I   reach   the   end   of   my   day   or   like   a   period   where   I   feel   like   I   need   to   stop,   you   know,   I&#39;ll   just   do   it.   Um   or   if   I   just   like   if   I&#39;m   it&#39;s   the   middle   of   the   day   and   I&#39;m   not   feeling   like,   you   know,   I&#39;m   just   not   feeling   energy   right   now,   maybe   I&#39;ll   just   stop   and   I&#39;ll   go,   you   know,   start   cooking   dinner   or   something.   Um   or   you   know,   go   do   some   shorts,   some   errands   around   the   house.   Um,   and   then   I   can   go   return   to   work   later.   And   it   just   it   just   feels   um   it   just   like   the   ability   to   switch   between   those   two   things,   it&#39;s   just   a   much   better   fit   for   me.   And   I   never   would   have   guessed   it   before   the   pandemic.
      </p>

        <cite>Conor</cite>
      <time>19:07</time>
      <p>
          Yeah,   I   would   have   to   say   that   I   don&#39;t   think   I   ever   it&#39;s   it   would   be   very   rare   if   I   ever   sort   of   start   my   day   and   end   my   day   within   like   a   nine   hour   um   like   fixed   window,   especially   due   to   the   fact   that   my   compile   time   is   like   40   plus   minutes.   I&#39;m   I&#39;m   constantly   like   in   the   evenings,   even   when   I&#39;m   quote   unquote   not   working,   like   just   still   iterating   on   something   that   I   know   if   it&#39;s   gonna   take   you   know   half   an   hour   plus   to   compile,   I&#39;ll   be   doing   my   own   stuff   and   I   can   still   I   can   still   like   make   quote   unquote   like   three   to   four   hours   of   progress   where   I&#39;m   really   only   working   for   like   less   than   an   hour,   but   it   that&#39;s   gonna   take   like   you   know,   half   a   day   of   compile   time   stuff,   then   uh   I&#39;ve   gotten   to   a   point   where   the   the   stuff   that   I&#39;m   doing,   um   most   of   it   is   like   strategy   and   planning.
      </p>

        <cite>Bryce</cite>
      <time>19:58</time>
      <p>
          And   so   if   I   do   have   a   c   a   task   that   involves   me   like   compiling,   or   like   for   me,   it&#39;s   the   it&#39;s   maybe   less   the   compile   time,   it&#39;s   more   like   building   like   getting   CI   results   back.   I&#39;m   lucky   in   that   now   I&#39;m   at   a   place   that   I   have   a   small   enough   portion   of   those   tasks   that   I   can   always   overlap   them   with   something   else.   But   uh,   but   I   my   one   of   my   ex-girlfriends   got   me   a   signed   copy   of   the   XKCD   comic   where   it&#39;s   showing   two   programmers   like   fighting   with   wooden   swords,   and   um   uh   there&#39;s   like   their   boss   saying,   Hey,   get   back   to   work,   and   one   of   them&#39;s   like   code&#39;s   compiling,   and   it   says   under   it   the   number   one   legitimate   excuse   for   programmers   slacking   off.   Um   yeah.   But   yeah,   like   like   I   I   don&#39;t   ever   really   work   nine   to   five   days,   but   um   I   have   I   s   I   have   days   that   are   meeting   days   and   I   have   days   that   are   work   days,   and   I   try   to   like   I   try   to   not   have   meetings   on   days   where   like   I   want   to   get   work   done.   Like   I   try   to   have   all   my   meetings   on   Mondays   and   Wednesdays,   but   um   it   it   ends   up   where   now   I   do   have   some   on   Tuesdays   and   Thursdays   because   I   have   some   committee   meetings   on   Tuesdays   and   some   other   work   meetings   on   Thursdays.   Um   uh   but   uh   you   know   like   I   might   every   now   and   then   I   have   that   rare   you   know   Tuesday   or   Thursday   where   I   have   nothing   to   do   and   I   can   just   say,   hey,   from   nine   to   five,   I&#39;m   just   gonna   work   on   this   thing.   And   I   usually   like   take   like   one   break   in   the   middle   of   the   day.   But   um   like   for   me   at   least   like   when   I   when   I   when   I   have   that   rare   like   chunk   of   like   free   time,   like   once   I   get   started   working   on   the   thing,   like   I   can   just   go   and   work   on   it   for   like,   you   know,   a   good   chunk   of   a   good   chunk   of   eight   hours.   Um   it&#39;s   just   like   the   getting   started   that&#39;s   uh   that&#39;s   challenging   and   finding   that   time.
      </p>

        <cite>Conor</cite>
      <time>21:54</time>
      <p>
          Yeah,   there&#39;s   a   huge   overhead   to   contact   switch   contact   switching.
      </p>

        <cite>Bryce</cite>
      <time>21:58</time>
      <p>
          Yeah.   Yeah.
      </p>

        <cite>Conor</cite>
      <time>22:01</time>
      <p>
          Alright,   so   back   to   we   went   on   a   couple   of   huge   tangents   there.   Um   but   we   got   we   got   one   tweet   read   at   least.
      </p>

        <cite>Bryce</cite>
      <time>22:10</time>
      <p>
          Yes.   All   right,   let&#39;s   let&#39;s   let&#39;s   go   back   to   another   user   tweet.
      </p>

        <cite>Conor</cite>
      <time>22:13</time>
      <p>
          Um   there   was   a   couple   tweets   along   the   same   lines.   So   Sean   posts   his   uh   car   crash   story.   Um   hopefully   hopefully   uh   everyone   has   listened   to   that   episode   that&#39;s   listening   to   this   episode   now.   If   not,   find   it   in   the   show   notes   and   sorry   for   the   spoiler.   A   couple   of   them   said   that   uh   feel   like   Sean   Parent   missed   the   this   is   from   Gregory   Thane.   Uh   feel   like   Sean   Parent   missed   the   punchline   of   his   story,   drove   Apple&#39;s   Porsche   too   fast   around   a   corner,   spun   out,   smashed   the   rear   end   uh   into   a   telephone   pole.   That&#39;s   a   rotate.   Um   which   I   thought   was   pretty   funny.   Um   and   yeah,   John   Mullins   said   the   same   thing.   That&#39;s   a   rotate   gone   wrong.
      </p>

        <cite>Bryce</cite>
      <time>22:55</time>
      <p>
          Um   audience,   uh   I   I   love   you   all.
      </p>

        <cite>Conor</cite>
      <time>23:04</time>
      <p>
          And   then   uh   there&#39;s   a   couple   different   um   folks   that   have   replied   or   retweeted   saying   that   uh   has   become   one   of   their   favorite   podcasts.   So   Pegman   was   one   of   those   individuals.   So   thanks.   And   also   uh   we&#39;re   getting   to   the   top.
      </p>

        <cite>Bryce</cite>
      <time>23:22</time>
      <p>
          Um   well   and   and   you&#39;re   you&#39;re   missing   the   one,   you   know,   people   are   pointing   out   the   new   name   for   the   podcast.
      </p>

        <cite>Conor</cite>
      <time>23:27</time>
      <p>
          Yeah,   yeah.   So   that&#39;s   the   one   we&#39;re   getting   to.   So   Sam   McDonald   on   uh   August   27th,   and   then   I   I   retweeted   this   saying   this   is   uh   unoffici   now   uh   officially   the   unofficial   title   of   this   podcast.   It&#39;s   probably   the   best   backronym   I&#39;ve   ever   uh   come   across.   And   Sam   tweeted,   ah,   always   glad   to   see   a   new   episode   of   ADSP   aka   a   discussion   with   Sean   Parent.   Which   is   amazing   because   uh   definitely   we&#39;ve   had   uh   Sean   on,   I   think   we&#39;ve   interviewed   him   three   times,   but   that&#39;s   been   split   into   like   eight   or   nine   episodes.
      </p>

        <cite>Bryce</cite>
      <time>24:03</time>
      <p>
          Like   eight,   yeah,   at   least   nine   episodes,   yeah.
      </p>

        <cite>Conor</cite>
      <time>24:06</time>
      <p>
          And   um   and   yeah,   Matt   Gobolt   also   tweeted   out   the   other   day   that   uh   he&#39;s   been   catching   up   on   the   podcast   and   really   enjoying   it   um   and   learning   about   things   he   didn&#39;t   think   he&#39;d   learn   about,   like   APL.   And   Matt,   for   those   of   you   that   don&#39;t   know,   also   has   his   own   podcast   called   Tooth   Compliment,   um,   which   is   definitely   worth   a   listen.   Oh,   snap!   And   I   didn&#39;t   even   see   this   one.   Um   another   backronym,   actually,   that&#39;s   a   scan   podcast.   That&#39;s   not   too   bad.   That&#39;s   uh   share   that&#39;s   from   share   the   parens   with   your   friends.   Which   is   an   amusing   um   an   amusing   uh   handle.   Anyways,   yeah,   we   were   supposed   to   talk   about   um   we   were   supposed   to   talk   about   something.
      </p>

        <cite>Bryce</cite>
      <time>24:54</time>
      <p>
          Yeah,   yeah,   well.   Because   I   didn&#39;t   get   the   memo.
      </p>

        <cite>Conor</cite>
      <time>24:56</time>
      <p>
          I   was   so   we&#39;re   gonna   have   to   save   it   till   I&#39;m   not   even   sure   because   I   it   would   have   been   nice   if   episode   42   was   talking   about   this.   But   so   while   you   were,   you   know,   moving   and   packing   and   we   weren&#39;t   recording   uh   during   August,   uh   on   my   other   podcast,   Arraycast,   I   learned   one   day   that   APL   and   Jay   have   inverse   scans.
      </p>

        <cite>Bryce</cite>
      <time>25:18</time>
      <p>
          So   so   okay,   yeah.   So   I   think   you   mentioned   this   to   me   somewhere,   and   I   expressed   some   confusion.
      </p>

        <cite>Conor</cite>
      <time>25:26</time>
      <p>
          I   think   you   just   saw   the   tweet,   and   then   you   were   like,   you   commented   on   it   and   were   like,   what&#39;s   an   inverse   scan?   And   then   you   said,   or   is   that   an   episode   of   ADSP?   And   I   said,   Yeah,   we&#39;ll   wait.   We&#39;ll   wait   to   talk   about   it.
      </p>

        <cite>Bryce</cite>
      <time>25:38</time>
      <p>
          So   explain   this   to   me   because   I&#39;m   really   I&#39;m   really   ha   so   like   a   scan   is   um   If   you   want,   you   tell   me   what   you   think   an   inverse   scan   is,   and   I&#39;ll   tell   you   a   lot   of   it.   Well,   well,   okay,   let   me   just   talk   through   this.   So   to   me,   a   scan   is   of   the   family   of   you   know,   a   reduction.   It   it&#39;s   where   where   a   reduction   produces   like   one   final   result,   a   scan   produces   all   these   intermediate   results.
      </p>

        <cite>Conor</cite>
      <time>26:02</time>
      <p>
          Really?   You   consider   a   scan   a   reduction?   That&#39;s   interesting.
      </p>

        <cite>Bryce</cite>
      <time>26:06</time>
      <p>
          Not   not   a   reduction.   I   consider   it   of   the   family   of   a   reduction.   Um   because   uh   you   know   it   it   produces   all   these   partial   sums.   Um   uh   I   think   there   are   a   lot   of   there   are   a   lot   of   problems   where   that   that   you   might   solve   with   a   reduction   where   a   modified   version   of   that   problem   might   be   solved   with   a   scam.   Um   yeah,   I   think   that   they&#39;re   very   similar.   Um   and   I   think   that   they   have   a   lot   of   similar   properties   in   terms   of   like   how   they   propagate   information   um   and   in   how   they   deal   with   things   like   commutativity   and   uh   associativity.   Yeah,   I&#39;m   gonna   stick   with   that.   I   I&#39;m   I&#39;m   I&#39;m   sticking   with   my   my   claim   here.   Um   so   then   the   idea   of   an   inverse   scan   immediately   makes   me   ask,   what   would   an   inverse   reduction   be?   And   I   have   no   idea.   Um   but   I   mean   I   guess   I   guess   I   would   I   would   think   that   an   inverse   reduction   would   mean   information   propagates   the   other   way.   Um   a   reduction   produ   produces   one   result   from   many,   so   maybe   an   inverse   reduction   would   um   send   one   result   out   to   minis.   But   I   I   don&#39;t   know   that   that   helps   me   at   all   guess   what   an   inverse   scan   is.
      </p>

        <cite>Conor</cite>
      <time>27:21</time>
      <p>
          Well,   so   here&#39;s   a   clue   is   that   in   APL   and   J,   I   I   believe   inverse   reductions   are   not   possible   at   all.
      </p>

        <cite>Bryce</cite>
      <time>27:32</time>
      <p>
          Okay.
      </p>

        <cite>Conor</cite>
      <time>27:33</time>
      <p>
          And   in   fact,   there   are   certain   inverse   scans   that   are   not   possible.   Only   certain   types   of   scans   can   be   inverted.   So   for   actually   I&#39;ll   pause   there   until   you   unless   if   you   want   another   hint.   And   then   if   you   want,   I   can   give   you   an   example   of   a   inverse   scan   that   can   be   inverted.   Or   a   scan   that   can   be   inverted   and   a   scan   that   cannot   be   inverted.
      </p>

        <cite>Bryce</cite>
      <time>27:53</time>
      <p>
          Yeah,   give   me   yes,   yes.
      </p>

        <cite>Conor</cite>
      <time>27:55</time>
      <p>
          You   want   those   hints?   Okay,   so   a   plus   scan   can   be   inverted,   but   a   max   scan   cannot.
      </p>

        <cite>Bryce</cite>
      <time>28:03</time>
      <p>
          What   properties   does   max   have   that   plus   does   not   have?
      </p>

        <cite>Conor</cite>
      <time>28:08</time>
      <p>
          This   is   fun.   Listeners   can   play   along.   Maybe   this   will   be   a   longer   episode.   We&#39;ll   just   we&#39;ll   go   way   past   the   30-minute   mark.
      </p>

        <cite>Bryce</cite>
      <time>28:15</time>
      <p>
          Um   What   properties   does   max   have   that   plus   doesn&#39;t   have?   Hmm.
      </p>

        <cite>Conor</cite>
      <time>28:21</time>
      <p>
          You   should   you   should   a   ask   yourself   what   properties   does   the   result   of   a   max   scan   have   versus   a   plus   scan?   Because   both   plus   and   max   are   both   associative   and   commutative.
      </p>

        <cite>Bryce</cite>
      <time>28:31</time>
      <p>
          So   Right,   right.   That&#39;s   property   wise   just   getting   to   that.
      </p>

        <cite>Conor</cite>
      <time>28:35</time>
      <p>
          Property-wise,   they&#39;re   very   similar.
      </p>

        <cite>Bryce</cite>
      <time>28:39</time>
      <p>
          Um   does   the   result   of   it   have.
      </p>

        <cite>Conor</cite>
      <time>28:41</time>
      <p>
          Um   And   here,   I&#39;ll   give   you   even   another   hint,   because   this   is   I&#39;m   getting   too   excited   sitting   here.   Tech   technically,   the   equivalent   of   an   inverse   scan   exists   as   an   algorithm   in   the   C   standard   library.
      </p>

        <cite>Bryce</cite>
      <time>29:00</time>
      <p>
          Is   it   like   an   adjacent   is   it   is   the   is   it   adjacent   difference?   It   is.   Yeah. Okay,   I   I   I   I   see   where   I   see   where   you&#39;re   going   with   this.   I   think.   Which   is   like   the   inverse   of   a   scan,   is   like   it&#39;s   like   an   adjacent   difference,   so   it&#39;s   just   like   the   localized   values.
      </p>

        <cite>Conor</cite>
      <time>29:25</time>
      <p>
          So   tell   me   to   stay   in   the   Ctopia   for   a   little   bit.   Um,   and   this   is   uh   this   was   first   pointed   out   to   me   by   Christabella   um   when   we   were   uh   discussing   whether   or   not   adjacent   difference   was   um   was   broken   or   not.   Because   I   I   have   for   a   long   time   maintained   that   adjacent   difference   is   broken   because   it   it   returns   you   n   elements   and   it   copies   the   first   element   of   the   input   range   to   be   the   first   element   of   the   output   range.   Listeners   of   this   podcast   have   probably   heard   me   say   that   like   three   or   four   times   by   now.   Chris&#39;s   take   was   that   it&#39;s   not   broken   because   the   desired   behavior   of   adjacent   difference   was   to   be   able   to   round   trip   with   partial   sum   to   get   back   the   original   input   sequence.   So   if   you   partial   sum   on   the   values   one,   one,   one,   one,   one,   you&#39;ll   get   back   one,   two,   three,   four,   five   as   the   partial   sum.   And   if   you   then   take   adjacent   difference,   you   can   round   trip   back   to   your   initial   input.   And   so   there&#39;s   this.
      </p>

        <cite>Bryce</cite>
      <time>30:29</time>
      <p>
          I   don&#39;t   see   how   you   would   round   trip   if   you   were   doing   maxes.
      </p>

        <cite>Conor</cite>
      <time>30:33</time>
      <p>
          Exactly,   yeah.   So   when   you   do   a   max   scan,   um,   you   cannot   do   the   inverse   of   that   because   you   have   you&#39;ve   lost   information   whenever   you   have   sort   of   local   minimums   in   between   values.   Whereas   a   plus   scan   inherently   encodes   every   single   piece   of   information   uh   in   between   like   adjacent   elements.
      </p>

        <cite>Bryce</cite>
      <time>30:55</time>
      <p>
          But   there   is   there   is   somehow   that   is   in   some   way   a   property   of   max   versus   plus.   I   don&#39;t   know   how   to.   And   you   know   what?   I   I   I   I   will   argue   that   there&#39;s   probably   there   are   I   assume   when   you   said   plus,   you   meant   plus   on   like   integers.
      </p>

        <cite>Conor</cite>
      <time>31:15</time>
      <p>
          As   opposed   to   I   don&#39;t   know,   like   plus   on   strings   or   some   other   Uh   well,   so   if   if   plus   is   defined   as   catenation,   it   would   still   work,   right?   If   you   had   the   characters   or   the   strings   A   B   C   D   E   F   G   as   all   individual   characters,   and   then   you   did   uh   What   about   what   about   on   like   floating   point   numbers?
      </p>

        <cite>Bryce</cite>
      <time>31:37</time>
      <p>
          Because   you&#39;re   gonna   have   information   loss   there.
      </p>

        <cite>Conor</cite>
      <time>31:39</time>
      <p>
          I   mean,   floating   point   is   like   there&#39;s   always   an   asterisk   next   to   that   because   of   NANDs   and   stuff   like   that.   But   I   mean   and   and   and   precision   and   whatnot,   but   arguably   you   can   get   back,   you   know,   minus   some   precision   and   minus   the   corner   cases   of   floating   point,   you   can   get   back   your   results.
      </p>

        <cite>Bryce</cite>
      <time>31:56</time>
      <p>
          Here&#39;s   another   one.   What   about   like   um   what   about   like   a   Boolean   operator?
      </p>

        <cite>Conor</cite>
      <time>32:00</time>
      <p>
          Like   um,   that   also   would   not   work,   yeah.
      </p>

        <cite>Bryce</cite>
      <time>32:03</time>
      <p>
          So   if   you   wanted   to   do   like   something   something   like   an   all   of,   you   know,   because   you&#39;re   gonna   lose   information   there   too.
      </p>

        <cite>Conor</cite>
      <time>32:09</time>
      <p>
          Yeah,   if   you   well,   so   all   of   is   a   reduction,   but   if   you   did   the   equivalent   like   logical   and   uh   scan   and   you   had   the   sequence   like   zero,   one,   zero,   one,   zero,   one,   that&#39;ll   return   you   zero,   one,   one,   one,   one,   one,   one,   one   to   the   end,   and   you&#39;re   only   gonna   be   able   to   find   you   know   the   first   element   that   was   a   one,   and   then   you&#39;ve   lost   all   information.   So   yes,   it   has   to   basically   your   binary   operation   combined   with   the   scan   has   to   encode   each   of   the   values   in   the   adjacent   values.   And   if   your   binary   operation   does   not   do   that,   then   it&#39;s   not   invertible.
      </p>

        <cite>Bryce</cite>
      <time>32:42</time>
      <p>
          So   so   that   property,   there   must   be   a   name   for   that   property.   I   wonder   if   there&#39;s   um   if   there&#39;s   a   mathematical   or   a   name   from   CS   theory   for   that   property.
      </p>

        <cite>Conor</cite>
      <time>32:52</time>
      <p>
          I   do   not   know   it   if   it   exists.   And   it&#39;s   it&#39;s   interesting.
      </p>

        <cite>Bryce</cite>
      <time>32:55</time>
      <p>
          Maybe   one   of   our   listeners   will.   I&#39;m   not   you.
      </p>

        <cite>Conor</cite>
      <time>32:57</time>
      <p>
          I&#39;m   not   sure   it&#39;s   so   much   a   property   of   the   binary   operation   as   it   is   like   the   resulting   scan   combined   with   the   binary   op.   Um   because   like   a   plus   like   if   you   go   one   plus   two,   you   get   three,   but   like   just   looking   at   the   binary   operation   on   its   own,   you&#39;ve   lost   all   information   there,   right?   The   same   way   if   you   have   like   one   max   two,   you   get   back   two.   You&#39;ve   lost,   was   it   two,   zero?   You   only   know   you   you&#39;ve   lost   information.   But   it&#39;s   it&#39;s   the   combination   of   the   scan   with   the   binary   operation.
      </p>

        <cite>Bryce</cite>
      <time>33:29</time>
      <p>
          Well,   it   it&#39;s   some   property   about   whether   there   exists   like   this   inverting   operation   where   you   can   take   you   can   can   you   take   two   of   the   results   that   are   next   to   each   other   and   recover   the   original   from   it.   Right?   Like,   is   there   some   operation   that   exists   that   you   can   take   two   of   the   partial   sums   and   get   back   the   original   values?
      </p>

        <cite>Conor</cite>
      <time>33:52</time>
      <p>
          Right,   yeah.
      </p>

        <cite>Bryce</cite>
      <time>33:54</time>
      <p>
          Yeah.   And   I   don&#39;t   know   what   that   so   yeah,   I   bet   that   there   is   I   bet   that   there   is   some   mathematical   term   uh   that   describes   this.
      </p>

        <cite>Conor</cite>
      <time>34:04</time>
      <p>
          Well   we&#39;ve   got   uh   we&#39;ve   I   don&#39;t   know   how   many,   we   get   on   average   like   a   thousand   listens   an   episode.   If   uh   somebody   will   if   you&#39;re   a   if   you&#39;re   a   math   background   at   us   uh   on   Twitter,   and   if   you   don&#39;t   have   Twitter,   you   can   find   us   on   uh   GitHub   on   our   get   on   my   GitHub   repo.   Or   just   go   to   the   website,   yeah,   and   that&#39;ll   take   you   to   the   GitHub   repo,   and   you   can   you   can   post   us   a   note.   Um   I&#39;d   be   very   curious   to   know.
      </p>

        <cite>Bryce</cite>
      <time>34:26</time>
      <p>
          So   so   is   so   how   different   is   an   APL   um   uh   inverse   scan   from   like   a   generalized   adjacent   difference?
      </p>

        <cite>Conor</cite>
      <time>34:36</time>
      <p>
          Um   a   generalized   adjacent   difference.   So   like   on   a   plus   scan,   it&#39;s   basically   the   exact   same   thing.
      </p>

        <cite>Bryce</cite>
      <time>34:44</time>
      <p>
          What   I   mean   is   like   adjacent   difference   is   not   like   it,   yeah,   I   believe   it   has   like   um   it   has   like   the   minus   hard   coded   in,   etc.
      </p>

        <cite>Conor</cite>
      <time>34:53</time>
      <p>
          Well,   it&#39;s   the   default   binary   operation.   Um   but   yeah,   so   like   if   you   do   an   inverse   plus   scan   on   one,   two,   three,   four,   five,   you   will   get   the   exact   same   result   if   you   did   an   adjacent   difference   on   one,   two,   three,   four,   five.
      </p>

        <cite>Bryce</cite>
      <time>35:08</time>
      <p>
          Um   and   it&#39;s   funny   because   we   also   have   a   name   for   it   for   the   generalized   adjacent   difference.
      </p>

        <cite>Conor</cite>
      <time>35:13</time>
      <p>
          Uh   we&#39;re   getting   adjacent   transform   in   ranges   because   that&#39;s   a   better   name.   And   that&#39;s   the   one   with   the   n   minus   one   behavior.
      </p>

        <cite>Bryce</cite>
      <time>35:20</time>
      <p>
          But   so   so   is   an   inverse   scan   adjacent   transform   in   C   ⁇ ?
      </p>

        <cite>Conor</cite>
      <time>35:26</time>
      <p>
          No.   Um   I   mean   an   inverse   scan   is   just   the   inverse   of   the   possible   scan.   Uh   we   Right,   right.
      </p>

        <cite>Bryce</cite>
      <time>35:37</time>
      <p>
          But   is   the   is   the   way   that   you   would   express   that   in   C   ⁇   adjacent   adjacent   transform?
      </p>

        <cite>Conor</cite>
      <time>35:43</time>
      <p>
          I   would   express   it   with   adjacent   difference,   because   it   actually   it   actually   that   means.
      </p>

        <cite>Bryce</cite>
      <time>35:47</time>
      <p>
          Right,   but   but   you   can&#39;t   always   but   that&#39;s   only   if   it&#39;s   a   plus   scan.
      </p>

        <cite>Conor</cite>
      <time>35:51</time>
      <p>
          Um   it&#39;s   uh   only   if   the   binary   operation   is   quote   unquote   invertible   for   the   lack   of   the   word   that   we   don&#39;t   have   for   it.   But   yes,   right.
      </p>

        <cite>Bryce</cite>
      <time>36:01</time>
      <p>
          But   well,   but   but   no   no,   it   it&#39;s   that&#39;s   only   if   the   uh   hang   on.   If   if   uh   if   the   inversion   operation   is   an   overload   of   adjacent   difference,   it   takes   a   binary   operation.   Yeah,   yeah,   yeah.   Okay,   yeah.
      </p>

        <cite>Conor</cite>
      <time>36:20</time>
      <p>
          Oh   sorry,   yeah,   that&#39;s   that&#39;s   what   I   was   like   I   I   was   thinking,   yeah,   if   you&#39;re   doing   multiple   like   a   multiply   scan,   you   can   get   the   inverse   by   just   overloading   the   we   only   we   only   added   the   overload   of   adjacent   difference   that   no   we   have.
      </p>

        <cite>Bryce</cite>
      <time>36:36</time>
      <p>
          No,   it&#39;s   been   there.   It&#39;s   been   there   since   C   then.
      </p>

        <cite>Conor</cite>
      <time>36:38</time>
      <p>
          Yeah,   yeah,   yeah.
      </p>

        <cite>Bryce</cite>
      <time>36:39</time>
      <p>
          Um   yeah.
      </p>

        <cite>Conor</cite>
      <time>36:41</time>
      <p>
          And   the   whole   other   extension   of   this   topic   is   that   you   get   this   inverse   scan   by   doing   uh   using   the   power   operator   in   APL,   which   usually   you   use   with   a   positive   number.   So   if   you   want   to   perform   some   function   two,   three,   four,   five   times,   you   go   power   two.   But   you   can   also   go   power   negative   one,   and   that   inverts   it.   And   that   works   on   a   variety   of   different   functions.
      </p>

        <cite>Bryce</cite>
      <time>37:02</time>
      <p>
          So   there&#39;s   also   explain   that.   Oh,   okay.   You   apply   the   power,   you   apply   the   power   operator   to   the   scan   operator.
      </p>

        <cite>Conor</cite>
      <time>37:10</time>
      <p>
          Correct.   Um,   and   so   then   you   What   happens?
      </p>

        <cite>Bryce</cite>
      <time>37:13</time>
      <p>
          What   happens   if   you   do   a   power   two   to   a   scan   operator?
      </p>

        <cite>Conor</cite>
      <time>37:17</time>
      <p>
          Uh   I   believe   it&#39;s   gonna   scan   twice.   Do   a   plus   scan   twice.   So   if   you   start   with   one,   one,   one,   one,   one,   you&#39;re   gonna   get   back   one,   two,   three,   four,   five.   And   then   if   you   do   that   again,   you&#39;re   gonna   get   back   one,   three,   six,   ten,   fifteen,   twifen,   yeah?   Is   that   right?
      </p>

        <cite>Bryce</cite>
      <time>37:32</time>
      <p>
          Yeah,   it&#39;s   almost   like   a   like   a   derivatives.
      </p>

        <cite>Conor</cite>
      <time>37:36</time>
      <p>
          Let&#39;s   uh   really   quickly   that   is   kind   of   like   a   derivative.   Do   you   want   me   to   share   my   screen?
      </p>

        <cite>Bryce</cite>
      <time>37:40</time>
      <p>
          Yeah,   go   for   it.   Users,   I   am   now   looking   at   a   screen   with   a   bunch   of   symbols.
      </p>

        <cite>Conor</cite>
      <time>37:46</time>
      <p>
          So   if   we   do   Quirky   symbols.   If   we   do   they   look   like   Egyptian   hieroglyphs.   That&#39;s   reduction.   So   we   got   plus   scan   once.   And   then   if   we   uh   do   power   two.
      </p>

        <cite>Bryce</cite>
      <time>38:00</time>
      <p>
          Okay,   the   power   symbol   is   a   little   asterisk   with   two   dots   above   it.
      </p>

        <cite>Conor</cite>
      <time>38:05</time>
      <p>
          It&#39;s   called   the   diurasis.   Diarysis?   Yeah.   Diurisis.   Um   it   actually   really   makes   a   lot   of   sense.   The   power   by   itself,   if   you   do   two   power   five,   you&#39;re   gonna   get   32   because   it&#39;s   uh   exponential.   Um   and   the   the   diurisis   typically   is   used   to   denote   an   operator.   So   it&#39;s   basically   like   just   a   power   operator,   it&#39;s   exactly   what   it   is.   Um   and   so   yeah,   if   you   instead   of   uh   if   I   go   iota   5   back   to   iota   5.
      </p>

        <cite>Bryce</cite>
      <time>38:42</time>
      <p>
          Wait,   why   did   you   not   use   iota   in   the   previous   example?
      </p>

        <cite>Conor</cite>
      <time>38:45</time>
      <p>
          Because   we   were   we   were   starting   with   uh   we   were   starting   with   five   ones   initially.   So   we   went   from   five   ones   to   one,   two,   three,   four,   five   because   of   the   plus   scan   to   one,   three,   six,   ten,   fifteen   because   of   the   power   two.   Um   but   if   we   want   to   do   an   inverse   scan,   we   have   to   start   with   iota   five   and   then   do   uh   plus   scan   plus   scan   power   negative   one,   and   this   is   gonna   give   us   back   five   ones.
      </p>

        <cite>Bryce</cite>
      <time>39:10</time>
      <p>
          So   you   want   to   see   some   why   wouldn&#39;t   we   do   why   couldn&#39;t   we   do   that?   I&#39;m   confused.   Well,   what&#39;s   the   one?
      </p>

        <cite>Conor</cite>
      <time>39:15</time>
      <p>
          Well,   so   if   we   did   it   with   let&#39;s   see   how   well   you   understand   it.   Say   if   we   do   if   we   replace   the   iota   five,   so   instead   of   doing   an   inverse   plus   scan   on   iota   five,   which   is   one,   two,   three,   four,   five,   we   do   it   on   five   ones.   What   are   we   gonna   get   back?   Do   you   know?
      </p>

        <cite>Bryce</cite>
      <time>39:30</time>
      <p>
          It&#39;s   gonna   be   like   one,   zero,   zero,   zero,   zero.
      </p>

        <cite>Conor</cite>
      <time>39:34</time>
      <p>
          Look   at   that.   Bryce   an   APL   expert.   So,   so   here&#39;s   here&#39;s   the   real   fun.   What   if   we   do   iota   inverse   on   one,   two,   three?   What&#39;s   this   gonna   give   us?
      </p>

        <cite>Bryce</cite>
      <time>39:50</time>
      <p>
          Iota   inverse.   Um   What   is   the   inverse   of   an   iota?   Wouldn&#39;t   that   be   like   a   sequence   of   ones?
      </p>

        <cite>Conor</cite>
      <time>39:58</time>
      <p>
          So   remember,   it   gives   us   back   it   basically   gives   it&#39;s   like   uh   what   did   Adam   from   Arraycast   um   and   dialogue   he   explained   it   as   sort   of   Jeopardy,   you   know?   It&#39;s   uh   what   gives   us   the   sequence   one,   two,   three   when   passed   to   IOTA?
      </p>

        <cite>Bryce</cite>
      <time>40:14</time>
      <p>
          Um   iota,   I   don&#39;t   think   of   it   iota   as   taking   I   think   of   it   iota   as   generating   the   sequence   one,   two,   three.
      </p>

        <cite>Conor</cite>
      <time>40:23</time>
      <p>
          Um   but   what   what   do   you   have   to   pass   to   it   in   order   to   get   it   to   generate   that?
      </p>

        <cite>Bryce</cite>
      <time>40:28</time>
      <p>
          Oh,   like   three?
      </p>

        <cite>Conor</cite>
      <time>40:30</time>
      <p>
          Exactly.
      </p>

        <cite>Bryce</cite>
      <time>40:32</time>
      <p>
          Oh,   interesting.
      </p>

        <cite>Conor</cite>
      <time>40:33</time>
      <p>
          So   APL&#39;s   got   inverse   schemes,   it&#39;s   got   inverse   iota.
      </p>

        <cite>Bryce</cite>
      <time>40:37</time>
      <p>
          Yeah.   But   it&#39;s   interesting,   it   gives   you   a   scalar,   a   scalar   result,   I   guess   that   makes   sense.
      </p>

        <cite>Conor</cite>
      <time>40:42</time>
      <p>
          I   mean,   it   seems   like   a   pretty   useless   um   algorithm   to   me.   Like   what&#39;s   what   are   you   gonna   use   an   inverse   iota   for,   other   than   to   check   maybe   that   you   have   a   monotonically   increasing   sequence   that   starts   at   one?
      </p>

        <cite>Bryce</cite>
      <time>40:54</time>
      <p>
          Yeah,   what   happens   what   happens   if   you   gave   it   if   you   gave   one,   two,   four   to   um   to   inverse   error?
      </p>

        <cite>Conor</cite>
      <time>41:01</time>
      <p>
          What   do   you   think&#39;s   gonna   happen?
      </p>

        <cite>Bryce</cite>
      <time>41:04</time>
      <p>
          Um   gives   you   an   error.   Gives   you   two,   maybe   domain   error.
      </p>

        <cite>Conor</cite>
      <time>41:11</time>
      <p>
          Because   it&#39;s   not   a   valid   IOTA   sequence.
      </p>

        <cite>Bryce</cite>
      <time>41:13</time>
      <p>
          Um   I   I   could   imagine   cases   where   that   would   be   useful.   Like   um   if   you   wanted   to   check   that   people   weren&#39;t   plugging   if   you   wanted   to   check   that   people   weren&#39;t   plugging   IOTA   sequences   into   your   unit   tests   because   you   wanted   actual   real   data,   you   know,   could   be   a   useful   algorithm.
      </p>

        <cite>Conor</cite>
      <time>41:33</time>
      <p>
          Yep.
      </p>

        <cite>Bryce</cite>
      <time>41:34</time>
      <p>
          But   yeah,   no,   it&#39;s   not   super   useful.
      </p>

        <cite>Conor</cite>
      <time>41:36</time>
      <p>
          It&#39;s   pretty   awesome   though.   They&#39;ve   we&#39;ve   got   so   any   and   basically   any   verb,   not   all   of   them,   a   lot   of   them   you   know   don&#39;t   work,   but   if   you   can   think   of   a   reasonable   inverse   for   a   function   that   you   have,   um   it   typically   is   there.
      </p>

        <cite>Bryce</cite>
      <time>41:48</time>
      <p>
          Uh   which   is   so   should   should   ranges   have   a   uh   should   we   have   a   range   adapter   that   uh   inverses   that   inverts   an   algorithm?   Would   that   even   make   no   that   I   don&#39;t   know   that   that   would   work,   but   or   it   should   should   we   have   some   CPO   that   inverts   another   CPO?   Oh   this   is   actually   this   has   actually   come   up.   We&#39;ve   talked   about   this   before.   We&#39;ve   talked   about   a   flip   operation.   Or   maybe   it   may,   I   don&#39;t   know   if   we   talked   about   it   here,   but   I   think   either   you   and   I   have   talked   about   it   or   it   exists   in   Boost   HANA,   right?
      </p>

        <cite>Conor</cite>
      <time>42:22</time>
      <p>
          Yeah.
      </p>

        <cite>Bryce</cite>
      <time>42:23</time>
      <p>
          Yeah,   yeah,   yeah.   I   think   either   you   and   I   or   Chris   developed   no,   I   think   it&#39;s   been   you   and   I   who   have   talked   about   it,   right?   Because   didn&#39;t   you   want   flip   for   some   Oh   yeah.
      </p>

        <cite>Conor</cite>
      <time>42:32</time>
      <p>
          I   I   I   go   on   and   on   about   flip.   It&#39;s   the   it&#39;s   the   C   combinator,   aka   Cardinal,   cardinal   bird.
      </p>

        <cite>Bryce</cite>
      <time>42:38</time>
      <p>
          So   if   but   if   we&#39;re   gonna   have   flip,   then   shouldn&#39;t   we   also   have   invert?
      </p>

        <cite>Conor</cite>
      <time>42:41</time>
      <p>
          I   mean,   invert   is   not   a   combinator.   Invert   is   just   a   cool   operator   that   that   takes   a   function   and   gives   it   a   lot.
      </p>

        <cite>Bryce</cite>
      <time>42:50</time>
      <p>
          The   way   I   imagine   it   works   in   APL,   just   based   on   those   examples   you   showed,   it&#39;s   not   something   where   it&#39;s   a   generic   algorithm,   right?   Like   it&#39;s   something   where   that   like   iota   know   like   it&#39;s   not   some   generic   thing   that   like   takes   iota   and   knows   how   to   invert   it.   Like   that&#39;s   like   some   special   wiring   of   logic   that   says,   hey,   like   here&#39;s   how   you   invert   an   IOTA.
      </p>

        <cite>Conor</cite>
      <time>43:11</time>
      <p>
          Yeah,   so   I   I   think   for   the   the   verbs   or   functions   like   where,   inverse,   and   scan,   those   do   have   like   a   table   lookup   where   it&#39;s   like,   oh,   if   it&#39;s   if   it&#39;s   a   plus   scan,   this   is   the   behavior   or   whatever.   However,   that   being   said,   I   do   know   that   if   you   build   up   a   point   free   or   tacit   expression   that   consists   purely   of   what?   Like   if   you   build   up   a   tacit   expression   or   point-free,   which   means   that   it   doesn&#39;t   mention   its   arguments.
      </p>

        <cite>Bryce</cite>
      <time>43:38</time>
      <p>
          I   was   about   like   you   use   some   words   there   and   then   you   like   glided   over   them   in   your   explanation.   Yeah,   continue.
      </p>

        <cite>Conor</cite>
      <time>43:44</time>
      <p>
          Uh   but   if   you   if   you   so   I   my   understanding   is   that   there&#39;s   some   sort   of   I   don&#39;t   know   what   the   r   algorithm   is,   like   recursive   def   descent   or   something   like   that,   but   like   a   composition   of   uh   functions   that   all   have   inverses   can   also   be   inverted.
      </p>

        <cite>Bryce</cite>
      <time>44:00</time>
      <p>
          Um   Yeah,   yeah,   yeah,   yeah.   Yeah,   yeah.   That   I   I&#39;m   sure   that   there&#39;s   some   generic   form   like,   but   but   there&#39;s   probably   cases   where   the   generic   form   falls   apart   or   something.   Um   falls   apart.   And   where   there&#39;s   probably   oh   let   me   put   it   in   the   right.   There&#39;s   probably   cases   where   there   are   generic   algorithms   where   there   where   there   are   invertible   algorithms   that   you,   the   user,   could   write,   but   that   um   you   would   have   to   somehow   customize   APL&#39;s   inversion   operation   to   explain,   like   imagine   that   IOTA   was   not   a   part   of   the   core   of   APL.   Um   and   you   wanted   to   write   your   own   IOTA.   You&#39;d   probably   have   to   express   to   it   in   some   way   how   that   inversion   would   work.
      </p>

        <cite>Conor</cite>
      <time>44:37</time>
      <p>
          So   this   is   at   the   limits   of   my   knowledge,   but   um   that   is   exactly   what   is   possible   in   J.   So   in   J,   I   believe   they   have   an   operator   called   Ubverse.   Um   why   it&#39;s   called   that,   I&#39;m   not   sure.   But   uh   Ubverse   enables   you   to   define   the   inverse   of   a   user-defined   function.   Um,   from   my   if   my   understanding   is   correct,   which   is   pretty   dope.
      </p>

        <cite>Bryce</cite>
      <time>45:00</time>
      <p>
          Well,   so   so   so   so   maybe   maybe   that&#39;s   a   thing   that   we   should   have   in   C.
      </p>

        <cite>Conor</cite>
      <time>45:04</time>
      <p>
          Like   we   should   have   ladies   and   gents.   Look   at   that.   J   APL,   the   array   languages,   they&#39;re   coming   to   C.   This   is   the   this   is   the   first   step.
      </p>

        <cite>Bryce</cite>
      <time>45:14</time>
      <p>
          You   you   act   you   act   as   if   like   I   can   just   like   unilaterally   decide   what   C   does.
      </p>

        <cite>Conor</cite>
      <time>45:21</time>
      <p>
          I   mean,   you   are   chair   of   Louvre,   right?   Isn&#39;t   that   like   half   the   reason   of   this   podcast?   Is   so   that   I   can   uh   slowly   warp   your   mind   until   uh   I   don&#39;t   know   about   this   proposal.   It   doesn&#39;t   mention   APL   anymore   anymore.
      </p>

        <cite>Bryce</cite>
      <time>45:32</time>
      <p>
          I   am   chair   as   library   evolution,   but   um   as   as   as   evidenced   as   recently   as   the   past   24   hours,   it   isn&#39;t   it   it   increasingly   becomes   clear   to   me   that   the   chair   is   more   a   servant   of   the   uh   of   of   the   participants   than   one   might   imagine.
      </p>

        <cite>Conor</cite>
      <time>45:55</time>
      <p>
          Well,   that   sounds   like   a   good   place   to   end   it.
      </p>

        <cite>Bryce</cite>
      <time>45:59</time>
      <p>
          Well,   or   let   me   let   me   put   it   another   way.   When   you&#39;re   chair,   your   job   is   no   longer   to   um   individually   contribute.   Your   job   is   to   help   make   sure   that   uh   that   everybody   else&#39;s   individual   contributions   get   uh   a   fair   hearing   and   uh   and   move   ahead   in   a   timely   fashion.
      </p>

        <cite>Conor</cite>
      <time>46:22</time>
      <p>
          A   moderator.
      </p>

        <cite>Bryce</cite>
      <time>46:24</time>
      <p>
          Yeah.   Yeah,   a   fancy   moderator.   Yeah.   And   and   I   some   somebody   just   told   me   that   it&#39;s   not   actually   required   for   me   to   move   to   New   York   to   take   over   Titus&#39;s   role   as   library   evolution   uh   chair.   I   assumed   that   there   was   some   throne   that   I   had   to   go   and   and   take   from   him,   but   uh   but   not   so   much.
      </p>

        <cite>Conor</cite>
      <time>46:48</time>
      <p>
          Thanks   for   listening.   We   hope   you   enjoyed   and   have   a   great   day.
      </p>