Opened 11 years ago

Closed 13 months ago

#11323 closed defect (fixed)

Fix ComplexNumber.__pow__ to allow float^complex

Reported by: kcrisman Owned by: AlexGhitza
Priority: major Milestone: sage-9.4
Component: basic arithmetic Keywords: plot li Li pow
Cc: slelievre, tmonteil Merged in:
Authors: Samuel Lelièvre Reviewers: Travis Scrimshaw
Report Upstream: N/A Work issues:
Branch: f86837f (Commits, GitHub, GitLab) Commit: f86837fc32a55794a785d14d56cb3dd3aaacadde
Dependencies: #24247 Stopgaps:

Status badges

Description

In sage.rings.complex_number.ComplexNumber.__pow__?? 

def __pow__(self, right, modulus):

    try:
        return (self.log()*right).exp()
    except TypeError:
        pass

makes it so that 

float(5)^(0.5+14.1347251*i)

doesn't work.

This means plotting even mpmath.li for complex values with a lambda function won't work nicely.

Change History (13)

comment:1 Changed 9 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:2 Changed 8 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:3 Changed 8 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:4 Changed 8 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:5 Changed 4 years ago by jdemeyer

  • Summary changed from allow floats to be taken to complex powers to Fix ComplexNumber.__pow__

comment:6 Changed 4 years ago by jdemeyer

  • Dependencies set to #24247

comment:7 follow-up: Changed 14 months ago by slelievre

  • Authors set to Samuel Lelièvre
  • Branch set to public/11323
  • Cc slelievre tmonteil added
  • Commit set to f86837fc32a55794a785d14d56cb3dd3aaacadde
  • Milestone changed from sage-6.4 to sage-9.3
  • Status changed from new to needs_review
  • Summary changed from Fix ComplexNumber.__pow__ to Fix ComplexNumber.__pow__ to allow float^complex

Please @kcrisman can you provide the plotting example you had in mind?

Please @tmonteil can you test on 32-bit?

New commits:

​f86837f11323: Fix complex number power so float^complex works

comment:8 in reply to: ↑ 7 Changed 14 months ago by kcrisman

Please @kcrisman can you provide the plotting example you had in mind?

From a decade ago?

I am not sure. I think I had attempted something like this directly, rather than parametrically. 

import mpmath
parametric_plot((lambda t: mpmath.ei(log(20)*(0.5+i*RR(t))).real, lambda t: mpmath.ei(log(20)*(0.5+i*RR(t))).imag), (0,14.1), rgbcolor=hue(0.7), plot_points=300) + point((mpmath.ei(log(20)*(0.5+i*14.1)).real, mpmath.ei(log(20)*(0.5+i*14.1)).imag), color='red',size=20)

where I used that on this domain the log integral is the exp integral of the log and somehow that avoided the problem.

But I can't remember what exactly I tried that failed, because presumably I discarded it. Sorry!

comment:9 Changed 14 months ago by mkoeppe

  • Milestone changed from sage-9.3 to sage-9.4

Moving to 9.4, as 9.3 has been released.

comment:10 Changed 13 months ago by tkarn

Should line 1695 isinstance(right, (int, long, Integer)) be changed to isinstance(right, (int, Integer)), for python 3, or should it be left as is for backwards compatibility?

comment:11 Changed 13 months ago by tscrim

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

It's not hurting anything by being there, so I would say leave it since it is not related to this ticket. It might also matter for 16-bit machines since this is Cython code (I'm not 100% sure of this however).

LGTM.

comment:12 Changed 13 months ago by slelievre

Thanks!

comment:13 Changed 13 months ago by vbraun

  • Branch changed from public/11323 to f86837fc32a55794a785d14d56cb3dd3aaacadde
  • Resolution set to fixed
  • Status changed from positive_review to closed
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