#19964: tight complex interval inverse
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Reporter: mmarco | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-7.2
Component: numerical | Resolution:
Keywords: interval, root | Merged in:
Authors: Miguel Marco | Reviewers: Vincent Delecroix
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/vdelecroix/19964 | d57fee2259bf69d0f0471f1bc89c3a81f1e12e27
Dependencies: | Stopgaps:
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Comment (by mmezzarobba):
lgtm except that I'd suggest the following change in order to really test
all possible cases:
{{{
@@ -1130,12 +1130,15 @@ cdef class
ComplexIntervalFieldElement(sage.structure.element.FieldElement):
Check that the code is valid in all regions of the complex
plane::
sage: rats = [15423/906, 337/59976, 145151/145112]
- sage: for a in rats:
- ....: for b in rats:
- ....: x = CIF(a, b)
- ....: assert (x * (~x) - 1).contains_zero()
- ....: x = -CIF(a,b)
- ....: assert (x * (~x) - 1).contains_zero()
+ sage: ivs = [RIF(aa, bb) for a in rats for b in rats
+ ....: for aa in [-a, a] for bb in [-b, b]
+ ....: if aa <= bb]
+ sage: for x in ivs:
+ ....: for y in ivs:
+ ....: z = CIF(x, y)
+ ....: inv = ~z
+ ....: assert ((z*inv - 1).contains_zero()
+ ....: or z.contains_zero() and
inv.real().is_NaN())
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/19964#comment:15>
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