Re: [Maxima-discuss] Maxima does not define hstep

[Jaime V. <vi...@fe...>]

On 28/11/24 11:50, Thomas D. Dean wrote:
> Maxima branch_5_47_base_1500_g32a79c344 https://maxima.sourceforge.io
> using Lisp GNU Common Lisp (GCL) GCL 2.6.14 git tag Version_2_6_14
> Distributed under the GNU Public License. See the file COPYING.
> Dedicated to the memory of William Schelter.
> The function bug_report() provides bug reporting information.
> (%i1) ??hstep
>
>
>  -- Function: hstep (<x>)
>      The Heaviside unit step function, equal to 0 if <x> is negative,
>      equal to 1 if <x> is positive and equal to 1/2 if <x> is equal to
>      zero.
>
>      If you want a unit step function that takes on the value of 0 at
>      <x> equal to zero, use 'unit_step'.
>
> (%o1)                                true
> (%i2) hstep(x);
> file_search1: pwilt not found in file_search_maxima,file_search_lisp.
>  -- an error. To debug this try: debugmode(true);
>
That message is apparently a compiler warning which only appears in some 
list flavors and does not seem to affect the computation of hstep:

Maxima branch_5_47_base_1500_g32a79c344https://maxima.sourceforge.io
using Lisp CLISP 2.49.93+ (2018-02-18)
(%i1) hstep(x);
(%o1)          hstep(x)
(%i2) hstep(0);
(%o2)          1/2
(%i3) plot2d(hstep(x),[x,-2,2])$

Everything works as expected in  Clisp

Maxima branch_5_47_base_1500_g32a79c344https://maxima.sourceforge.io
using Lisp Clozure Common Lisp Version 1.12.2 (v1.12.2) LinuxX8664

(%i1) hstep(x);
;Compiler warnings for "/home/villate/.local/share/maxima/branch_5_47_base_1500_g32a79c344/share/diffequations/pwilt.lisp" :
;   In PWILT-ADD-PARTS: Local function or macro name MERGE shadows standard CL definition.
(%o1)          hstep(x)
(%i2) hstep(0);
(%o2)          1/2
(%i3) plot2d(hstep(x),[x,-2,2])$

In spite of the warning, hstep(0) and the plot work correctly.

Regards,

Jaime

P.S. I can no longer build Maxima with the same SBCL version that I used 
a few weeks ago. Is anyone else having that problem?