Opened 9 years ago

Closed 5 years ago

#10074 closed enhancement (fixed)

special values of lesser hyperbolic functions

Reported by: kcrisman Owned by: burcin
Priority: minor Milestone: sage-6.4
Component: symbolics Keywords: sech, coth, csch
Cc: Merged in:
Authors: Ralf Stephan Reviewers: Frédéric Chapoton
Report Upstream: N/A Work issues:
Branch: e064ff3 (Commits) Commit: e064ff3a8cc50f28ccdac848c4eab688875d26e8
Dependencies: Stopgaps:

Description

Even though Maxima can evaluate sech(0), Sage does this: 

sage: cosh(0)
1
sage: sech(0)
sech(0)

It seems reasonable to fix this. Part of this is probably that sech is not a !GiNaC function.

Change History (14)

comment:1 Changed 8 years ago by benjaminfjones

Is there a way of initializing a Ginac / Pynac function using a symbolic expression? It would be nice to be able to initialize sech by calling simply: 

GinacExpression.__init__(self, '1/cosh', ...

And the result would behave just like defining sech(z) = 1/cosh(z) in Sage. Then we'd get (as in sage-5.0.beta9): 

sage: sech(z) = 1/cosh(z)
sage: sech(0)
1

Maybe this is naive...

comment:2 Changed 6 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:3 Changed 6 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:4 Changed 6 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:5 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:6 Changed 5 years ago by rws

  • Summary changed from Improve less-used hyperbolic functions to special values of lesser hyperbolic functions

comment:7 Changed 5 years ago by rws

  • Branch set to u/rws/improve_less_used_hyperbolic_functions

comment:8 Changed 5 years ago by rws

  • Authors set to Ralf Stephan
  • Commit set to b1833cb5e3f2e204e4ec966e404a42835a82f418
  • Status changed from new to needs_review

New commits:

​b1833cb10074: special values of coth, sech, csch

comment:9 Changed 5 years ago by chapoton

  • Status changed from needs_review to needs_work

badly formatted doc

comment:10 Changed 5 years ago by git

  • Commit changed from b1833cb5e3f2e204e4ec966e404a42835a82f418 to 507dc57324d5cdada41940aa9d61120c0846f95a

Branch pushed to git repo; I updated commit sha1. New commits:

​507dc5710074: cosmetics

comment:11 Changed 5 years ago by rws

  • Status changed from needs_work to needs_review

comment:12 Changed 5 years ago by chapoton

  • Branch changed from u/rws/improve_less_used_hyperbolic_functions to public/ticket/10074
  • Commit changed from 507dc57324d5cdada41940aa9d61120c0846f95a to e064ff3a8cc50f28ccdac848c4eab688875d26e8
  • Reviewers set to Frédéric Chapoton

Looks good to me, if you agree with my small changes, you can set that to pos.rev.

New commits:

​16323a3Merge branch 'u/rws/improve_less_used_hyperbolic_functions' into 6.5.b6
​e064ff3trac #10074 review commit

comment:13 Changed 5 years ago by rws

  • Status changed from needs_review to positive_review

OK. Thanks.

comment:14 Changed 5 years ago by vbraun

  • Branch changed from public/ticket/10074 to e064ff3a8cc50f28ccdac848c4eab688875d26e8
  • Resolution set to fixed
  • Status changed from positive_review to closed
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