#13110: ComplexNumber should be able to accept the Python complex type
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Reporter: eviatarbach | Owner: jason, jkantor
Type: defect | Status: needs_review
Priority: major | Milestone: sage-5.10
Component: numerical | Resolution:
Keywords: complex, beginner | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Travis Scrimshaw | Merged in:
Dependencies: | Stopgaps:
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Comment (by nbruin):
The ticket states that `ComplexNumber(complex(...))` doesn't work and
proceeds by implementing a more elaborate string parser. That's not the
most obvious way of soving the ticket:
- a python `complex` already has a nice `.real()` and `.imag()`, so
stuffing them together in a string to just pry them apart is not a smart
move. Doing
{{{
if isinstance(s_real, complex):
s_real, s_imag = s_real.real(), s_real.imag()
}}}
makes much more sense to solve the problem at hand.
- The fact that `ComplexNumber` would assemble a complex number from
numerical input by converting to a string is ludicrous in its own right:
If you're handed real and imaginary parts in numerical form, you should
NOT be converting to strings as an intermediate. That's just asking for
precision loss (and horrible performance).
I realize that we have the documentation:
{{{
def create_ComplexNumber(s_real, s_imag=None, int pad=0, min_prec=53):
Return the complex number defined by the strings s_real and
s_imag as an element of ``ComplexField(prec=n)``,
where n potentially has slightly more (controlled by pad) bits than
given by s.
}}}
According to that documentation, the proposed input is not valid anyway.
By changing that you're changing the interface the routine offers. That's
fine, but once you start changing it, you should ''improve'' it.
Note that `CC(complex("1+2j"))` already works. By the looks of it,
`CC.__call__` is already taking a much saner approach. Perhaps
`ComplexNumber` should share more with that routine? Or be documented that
people should really use `CC(...)`? or perhaps `ComplexNumber` can be
deprecated altogether?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13110#comment:13>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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