real and imag of complex should return float

[eviatarbach]

real(z) and imag(z), where z is complex, as of now returns a complex. It should return a float, since that makes it consistent with real(CC(3, 4)), for example. It also fixes problems with plotting the real or imaginary parts of complex functions.

Component: symbolics

Author: Eviatar Bach

Reviewer: Punarbasu Purkayastha

Merged: sage-5.12.beta3

Issue created by migration from https://trac.sagemath.org/ticket/15032

[eviatarbach]

comment:1

Patchbot apply trac15032.2.patch

[ppurka]

comment:2

The new functions needs some doctests to check that the type is correct.

I am actually quite surprised by the inconsistency of the Sage implementation. self.real contains the number in the case of python's complex but it is a function in Sage's implementation. Do you know what is the reason behind the function in the Sage implementation?

sage: a = CC(1)     
sage: a.real
<function real>
sage: a = complex(1)
sage: a.real
1.0

EDIT Actually just shift the doctests to within the __call__ functions.

[eviatarbach]

comment:3

Okay, I'll add the tests.

I think the reason for the functions is that it's converting from MPFR. It could be changed with the @property decorator so that self.real will work.

[eviatarbach]

Attachment: trac15032.3.patch.gz

[eviatarbach]

comment:4

I added the tests to __call__ but also left the other ones intact, since the __call__ ones aren't visible in the documentation.

[ppurka]

comment:5

Looks good to me. All tests pass in sage/rings and sage/functions

Patchbot apply trac15032.3.patch

[ppurka]

Author: Eviatar Bach

[ppurka]

Reviewer: Punarbasu Purkayastha

[jdemeyer]

Merged: sage-5.12.beta3