Opened 3 years ago

Last modified 2 years ago

#21444 needs_review defect

SR.wild and maxima don't mix

Reported by: nbruin Owned by:
Priority: major Milestone: sage-duplicate/invalid/wontfix
Component: symbolics Keywords:
Cc: rws Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

This came up in ask-sage:

sage: tanh(SR.wild(0)) #for references; this works
tanh($0)
sage: coth(SR.wild(0))
ValueError: The name "" is not a valid Python identifier.

The traceback shows that this error happens when trying to parse back a maxima result with bare _SAGE_VAR_ in it (i.e., a sage variable with an empty name)

It seems #20134 is implicated.

Another problem arises when a wildcard expression gets sent to maxima:

sage: sin(SR.wild(0)).simplify_full()
TypeError: ECL says: THROW: The catch MACSYMA-QUIT is undefined.

It may be that we can resolve both errors by ensuring that wildcards roundtrip properly to maxima (e.g., convert them to _SAGE_WILDCARD_0 rather than the syntactically illegal _SAGE_VAR_$0 and parse them back properly too).

It may also be that by giving coth and friends a slightly different treatment we can get them in line with tanh etc.

Change History (7)

comment:1 Changed 3 years ago by nbruin

  • Component changed from PLEASE CHANGE to symbolics

comment:2 Changed 3 years ago by nbruin

  • Type changed from PLEASE CHANGE to defect

comment:3 follow-up: Changed 3 years ago by rws

This works in 7.4beta3, i.e., the coth(SR.wild(0)) part, not the simplify of course.

Last edited 3 years ago by rws (previous) (diff)

comment:4 in reply to: ↑ 3 Changed 3 years ago by kcrisman

This works in 7.4beta3, i.e., the coth(SR.wild(0)) part, not the simplify of course.

I was figuring that a Pynac upgrade might do it, because I remembered you adding those functions recently. Should we have one ticket just to doctest that works, and then leave this ticket for the round-trip issue?

comment:5 Changed 3 years ago by rws

Yes please.

comment:6 Changed 3 years ago by kcrisman

See #21455

comment:7 Changed 2 years ago by rws

  • Milestone changed from sage-7.4 to sage-duplicate/invalid/wontfix
  • Status changed from new to needs_review

Probably a duplicate of #16335.

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