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CL, NaNs and infinities.
by Marco Antoniotti 04 Sep '19

04 Sep '19

Hello, I am fooling around IEEE 754 (don't ask why) and I started asking questions to various CL impleentations about the usual corner cases. Take for example the function ACOS. prompt> (acos 42.0) #C(0.0 4.430675) Seems legit, according to CLHS. Now, suppose you do (e.g. in CCL) CCL prompt> (acos 1D++0) ; 1D++0 is positive infinity Error: FLOATING-POINT-INVALID-OPERATION detected performing * on (0.0D0 1D++0) While executing: CCL::%DOUBLE-FLOAT*-2!, in process Listener(4). Type cmd-. to abort, cmd-\ for a list of available restarts. Type :? for other options. 1 > SBCL prompt> (acos 1D++0) ; No, you can't write that in SBCL, but ber with me. arithmetic error FLOATING-POINT-INEXACT signalled [Condition of type FLOATING-POINT-INEXACT] Restarts: 0: [RETRY] Retry SLIME REPL evaluation request. 1: [*ABORT] Return to SLIME's top level. 2: [REMOVE-FD-HANDLER] Remove #<SB-IMPL::HANDLER INPUT on descriptor 8: #<CLOSURE (LABELS SWANK/SBCL::RUN :IN SWANK/BACKEND:ADD-FD-HANDLER) {12974D1D}>> 3: [ABORT] Exit debugger, returning to top level. LW prompt> (acos 1D++0) #C(6.283185307179586D0 1D+-0 #| 1D+-0 is double-float not-a-number |#) ACOS (and friends) also take complex numbers. CL-USER 19 > (acos #C( 42 42)) #C(0.785469 -4.7773905) Things get even more interesting when you pass to ACOS (and friends) a complex number with an infinity RE or IM part. LW prompt> (acos (complex 42 1D++0)) #C(1D+-0 #| 1D+-0 is double-float not-a-number |# -1D++0 #| -1D++0 is double-float minus-infinity |#) CCL prompt> (acos (complex 1.0 1D++0)) #C(1.5707963267948966D0 -1D++0) SCBL prompt> (acos (complex 1.0 1D++0)) arithmetic error FLOATING-POINT-INEXACT signalled [Condition of type FLOATING-POINT-INEXACT] Restarts: 0: [RETRY] Retry SLIME REPL evaluation request. 1: [*ABORT] Return to SLIME's top level. 2: [REMOVE-FD-HANDLER] Remove #<SB-IMPL::HANDLER INPUT on descriptor 8: #<CLOSURE (LABELS SWANK/SBCL::RUN :IN SWANK/BACKEND:ADD-FD-HANDLER) {12974D1D}>> 3: [ABORT] Exit debugger, returning to top level. Now, now, now. We do not like this state of affairs, do we? So, the question is: what should ACOS (and friends) do in these cases? What about the LIA ISO/IEC 10967 standards? All the best Marco -- Marco Antoniotti, Associate Professor tel. +39 - 02 64 48 79 01 DISCo, Università Milano Bicocca U14 2043 http://bimib.disco.unimib.it Viale Sarca 336 I-20126 Milan (MI) ITALY Please check: http://cdac2019.lakecomoschool.org Please check: http://troncopackage.org Please check: https://www.frontiersin.org/research-topics/7394/network-bioscience Please note that I am not checking my Spam-box anymore. Please do not forward this email without asking me first (cum grano salis).

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Test. Please ignore.
by Marco Antoniotti 02 Sep '19

02 Sep '19

Cheers — Marco

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FP infinities on CL
by Marco Antoniotti 31 Aug '19

31 Aug '19

Hi I just posted a longish thing on CLL regarding FP IEEE 754 infinities handling in CL. I invite you all to look at it and comment; unless you feel it is appropriate to re-post here. Thanks MA -- Marco Antoniotti, Associate Professor tel. +39 - 02 64 48 79 01 DISCo, Università Milano Bicocca U14 2043 http://bimib.disco.unimib.it Viale Sarca 336 I-20126 Milan (MI) ITALY Please check: http://cdac2019.lakecomoschool.org Please check: http://troncopackage.org Please check: https://www.frontiersin.org/research-topics/7394/network-bioscience Please note that I am not checking my Spam-box anymore. Please do not forward this email without asking me first (cum grano salis).

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Fwd: Creating large arrays
by Burton Samograd 18 Jul '19

18 Jul '19

Hello, Someone on the LISP HUG Mailing list was recently trying to allocate a 4GB array and found that it was failing. I was recently thinking about such problems wishing there were sparse arrays in CL; I ended up making something called ’Spaces’ which potentially solve the problem. Below is a letter to HUG that I sent to someone outlining my solution to the problem. I thought some of you might find it useful as well, or might want to discuss this data structure, which I think is new, or at least I have never read nor heard of it before I invented it a couple of months ago. Burton > Begin forwarded message: > > From: Burton Samograd <busfactor1(a)icloud.com> > Subject: Re: Creating large arrays > Date: July 18, 2019 at 2:45:14 PM MDT > To: lisp(a)gmx.com > Cc: lisp-hug(a)lispworks.com > > >> Are there other fast-access data structures with no such limitations, on >> LispWorks? >> >> >> Thank you again, >> >> Priyadarshan > > I have created something called ’N-Dimensional Sparse Spaces’ as a solution to the large array allocation problem. > > > > > This initial implementation is one to replace a set of random points within an N-Dimensional Sparse Grid addressed using integers, hence the use of #’= in #’make-space. > > It is more generallized using other equals functions such as #’eql (so you can use symbols, and hence make an addressable symbol space), #’equals and #equalp letting you use S-Expressions as your addresses. > > I have a more general implementation somewhere in my code, but the above image is the code I initially wrote that can be springboarded off of to create your own implementation. > > One trick I have thought of is to, after you have completed your work with the space, is to compile it to a more suituable data structure for read-only access. > > The sparce space is for editing and loading of the data you want to work with. A complied space is for reading data from the space, giving up generality. > > Feel free to write me to discuss this data structure further if you have any questions or comments on its usefulness and generality and applicability to your problem. > > Burton Samograd > BusFactor1 Inc.

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reading s-expressions from a file
by Alexandre Rademaker 26 Jun '19

26 Jun '19

The “read” function makes really easy to read a bunch of s-expressions from a file, but how can I keep track of the line number where the expressions were in the file? Any ideia? Alexandre Sent from my iPhone

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Re: reading s-expressions from a file
by Jack Harper 26 Jun '19

26 Jun '19

Alexandre, be careful with Lisp control characters embedded - back quotes, commas etc. Jack Harper Secure Outcomes Inc Evergreen, Colorado USA At 10:27 AM 6/26/2019, LuÃs Oliveira wrote: >On Wed, Jun 26, 2019 at 5:19 PM Alexandre Rademaker ><arademaker(a)gmail.com> wrote: > > The âreadâ function makes really easy to > read a bunch of s-expressions from a file, but > how can I keep track of the line number where the expressions were in the file? > >One way to do it is to define a stream that keeps track of the current >line. Here's an example of such a stream: ><https://github.com/cl-stream/cl-stream/blob/master/line-tracking-stream.lisp>. > >-- >LuÃs Oliveira >http://kerno.org/~luis/ ---------------------------------------------------------------------------------- Jack Harper, President Secure Outcomes Inc 2942 Evergreen Parkway, Suite 300 Evergreen, Colorado 80439 USA 303.670.8375 303.670.3750 (fax) http://www.secureoutcomes.net for Product Info.

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Re: reading s-expressions from a file
by Jack Harper 26 Jun '19

26 Jun '19

Alexandre, be careful with Lisp control characters embedded - back quotes, commas etc. Jack Harper Secure Outcomes Inc Evergreen, Colorado USA At 10:27 AM 6/26/2019, LuÃs Oliveira wrote: >On Wed, Jun 26, 2019 at 5:19 PM Alexandre Rademaker ><arademaker(a)gmail.com> wrote: > > The âreadâ function makes really easy to > read a bunch of s-expressions from a file, but > how can I keep track of the line number where the expressions were in the file? > >One way to do it is to define a stream that keeps track of the current >line. Here's an example of such a stream: ><https://github.com/cl-stream/cl-stream/blob/master/line-tracking-stream.lisp>. > >-- >LuÃs Oliveira >http://kerno.org/~luis/ ---------------------------------------------------------------------------------- Jack Harper, President Secure Outcomes Inc 2942 Evergreen Parkway, Suite 300 Evergreen, Colorado 80439 USA 303.670.8375 303.670.3750 (fax) http://www.secureoutcomes.net for Product Info.

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Reading S-expressions from files
by Alexandre Rademaker - alexrad＠br.ibm.com 26 Jun '19

26 Jun '19

The “read” function makes really easy to read a bunch of s-expressions from a file, but how can I keep track of the line number where the expressions were in the file? Any ideia? Sent from my iPhone

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Re: CDR-14 and optional modules
by Marco Antoniotti 01 Jun '19

01 Jun '19

Hi if you don’t load code that implements a feature you wouldn’t be able to push a feature onto the *FEATURES* list. That is, unless you are a jerk :) :) :) and push stuff onto the *FEATURES* list just for the heck of it, or as a, I’d say tasteless, joke :) :) :) Cheers MA > On May 12, 2019, at 22:04 , Michael Raskin <38a938c2(a)rambler.ru> wrote: > > Hello > I look at CDR-14 that says about putting :CDR-NN symbols into > *features* if implementation purports to implement a CDR. What is the > recommended behaviour in the case when the implementation provides > a loadable module to support a CDR? Should the feature be always present > or only appear when the module is loaded? > What are the opinions? > > Thank you, good bye > Michael Raskin > > > -- Marco Antoniotti

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Reading spreadsheets
by Nick Levine 22 May '19

22 May '19

Has anyone tried reading a google spreadsheet from lisp (Allegro)? Searching produced a couple of libraries for this, and neither of them compiled cleanly (which is not where I wanted to spend my morning). - nick

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