Opened 4 months ago

Closed 3 months ago

#32396 closed enhancement (fixed)

Absolute value function for scalar fields

Reported by: gh-mjungmath Owned by:
Priority: major Milestone: sage-9.5
Component: manifolds Keywords:
Cc: egourgoulhon, tscrim Merged in:
Authors: Michael Jung Reviewers: Travis Scrimshaw
Report Upstream: N/A Work issues:
Branch: 2095de3 (Commits, GitHub, GitLab) Commit: 2095de3117eb3a6cee9f4a928d0b8fd2e4496e85
Dependencies: Stopgaps:

Status badges

Description (last modified by gh-mjungmath)

Currently, the abs operator cannot be applied to scalar fields: 

sage: M = Manifold(2, 'M', structure='topological')
sage: X.<x,y> = M.chart()
sage: f = M.scalar_field({X: x*y}, name='f', latex_name=r"\Phi")
sage: abs(f)
Traceback (most recent call last)
...
TypeError: bad operand type for abs(): 'ScalarFieldAlgebra_with_category.element_class'

In this ticket, we add this feature.

Change History (15)

comment:1 Changed 4 months ago by gh-mjungmath

  • Branch set to u/gh-mjungmath/abs_function_for_scalar_fields

comment:2 Changed 4 months ago by gh-mjungmath

  • Commit set to fcd64c9c1ecc5e68ec5e42125f7d403138fe7b0a
  • Status changed from new to needs_review

New commits:

​fcd64c9Trac #32396: add __abs__ to chart_func and scalarfield

comment:3 Changed 4 months ago by gh-mjungmath

  • Description modified (diff)

comment:4 Changed 4 months ago by gh-mjungmath

  • Description modified (diff)

comment:5 Changed 4 months ago by tscrim

  • Reviewers set to Travis Scrimshaw
  • Status changed from needs_review to positive_review

LGTM.

comment:6 Changed 4 months ago by gh-mjungmath

Thank you for the review!

comment:7 Changed 4 months ago by egourgoulhon

Thanks for implementing this. Any reason for the choice of Abs rather than abs for the function name?

Last edited 4 months ago by egourgoulhon (previous) (diff)

comment:8 follow-up: Changed 4 months ago by gh-mjungmath

No particular reason. Do you prefer abs or maybe |.|?

Last edited 4 months ago by gh-mjungmath (previous) (diff)

comment:9 in reply to: ↑ 8 Changed 4 months ago by egourgoulhon

Replying to gh-mjungmath:

No particular reason. Do you prefer abs or maybe |.|?

I don't have any strong preference. abs sounds more inline with other function names in Sage, while |.| is closer to mathematical notation, so I would slightly prefer the latter. Travis, what do you think?

comment:10 Changed 4 months ago by tscrim

I am slightly worried about possible ambiguity with |.|. I might go with abs over Abs just because of \lvert compared to \lVert and to match Sages's abs. However, I didn't (and still don't) really care for which one as it is clear documentation-wise what it is doing (and hidden from the causal user). So I am not the person to ask for a real opinion on this.

comment:11 Changed 4 months ago by git

  • Commit changed from fcd64c9c1ecc5e68ec5e42125f7d403138fe7b0a to 2095de3117eb3a6cee9f4a928d0b8fd2e4496e85
  • Status changed from positive_review to needs_review

Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:

​2095de3Trac #32396: adjust abs function name to general Sage convention

comment:12 Changed 4 months ago by gh-mjungmath

Alright, I changed it to abs with small letters. I find it a strong argument to say that this follows general Sage convention.

comment:13 Changed 4 months ago by tscrim

  • Status changed from needs_review to positive_review

Thanks. I am setting back to a positive review.

comment:14 Changed 4 months ago by mkoeppe

  • Summary changed from Abolute value function for scalar fields to Absolute value function for scalar fields

comment:15 Changed 3 months ago by vbraun

  • Branch changed from u/gh-mjungmath/abs_function_for_scalar_fields to 2095de3117eb3a6cee9f4a928d0b8fd2e4496e85
  • Resolution set to fixed
  • Status changed from positive_review to closed
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