[Maxima] makelist(): argument size appears restricted to integer -- RFC

Barton Willis willisb at unk.edu
Tue Apr 21 09:37:49 CDT 2009


The user documentation doesn't mention it, but the difference between the 
third and fourth
arguments to makelist must be a Common Lisp fixnum. The CL standard 
doesn't specify the size 
in bits of a fixnum. On one compiler I tried, 2^28 is a fixnum, but 2^29 
isn't. Since
30! > 2^107 >>> 2^28,  there is no possibility of using makelist to build 
a list of
30! integers. 

The restriction to a CL fixnum is reasonable. A list of a few million 
(2^20) 
integers is about all that Maxima can handle--lists of expressions cannot 
exceed about
10^5 or so items.

If all you want to do is sum(k^2,k,1,30!), Maxima has no problem with 
that:

(%i3) sum(k^2,k,1,n), simpsum;
(%o3) (2*n^3+3*n^2+n)/6

(%i4) subst(n=30!,%);
(%o4) 
6220982362625999092956982917190059580036449791652138192382722560208520946113558464972718080000000

(%i5) bfloat(%);
(%o5) 6.220982362625999b96

Barton

maxima-bounces at math.utexas.edu wrote on 04/21/2009 06:06:38 AM:

> [image removed] 
> 
> [Maxima] makelist(): argument size appears restricted to integer -- RFC
> 
> Robyn Dawn Hannigan 
> 
> to:
> 
> Maxima mailing list
> 
> 04/21/2009 07:10 AM
> 
> Sent by:
> 
> maxima-bounces at math.utexas.edu
> 
> Hello List,
> 
> In the last few days i have been experimenting with list programming. i
> came across the following (IMO) defficiency in makelist.
> 
> >From the manual:
> 
--------------------------------------------------------------------------
> Constructs and returns a list, each element of which is generated from
> expr. 
> makelist (expr, i, i_0, i_1) returns a list, the j'th element of which
> is equal to ev (expr, i=j) for j equal to i_0 through i_1. 
> makelist (expr, x, list) returns a list, the j'th element of which is
> equal to ev (expr, x=list[j]) for j equal to 1 through length (list). 
> 
-----------------------------------------------------------------------------
> 
> This is all well and good. 
> The following error was observed ion a wxMaxima session. 
> 
> (%i1) s(n):= block([n:n],
> apply("+",map(lambda([x],x^2),makelist(x,x,1,n))))$
> (%i2) s(30!);
> If 4 arguments are given to MAKELIST, the difference of the 3rd and 4th
> arguments should evaluate to a non-negative integer:
> 265252859812191058636308479999999
> #0: s(n=265252859812191058636308480000000)
>  -- an error.  To debug this try debugmode(true);
> 
> 
> 
> What i assume this means is that the bug can be reduced to 
> 
> makelist(x,x,1,265252859812191058636308479999999)
> 
> Which does indeed produce the same error message on my equipment:
> wxMaxima 0.8.1 http://wxmaxima.sourceforge.net
> Maxima 5.17.1 http://maxima.sourceforge.net
> Using Lisp SBCL 1.0.27-r10-gentoo
> 
> Can anyone help me understand where it came from please?
> Many Thanks,
>    Robyn
> 
> 
> _______________________________________________
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> Maxima at math.utexas.edu
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