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Avoid intermediate overflow and underflow in complex abs - #583
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Complex
abs()squares both components before taking the square root. Without VML,abs(3e200 + 4e200j)returns infinity andabs(3e-200 + 4e-200j)returns zero, although their magnitudes are representable. This also breaks normalization insign().Use
hypot(), already used by the complex logarithm and square-root helpers. Add regressions for large/small values, strided and in-place evaluation, and nonfinite inputs; retain the complex result type.Validated on Windows/MSVC, Python 3.13 and NumPy 2.3.5 without VML: all 6,045 tests pass, including from the built wheel. The three new tests fail on the baseline. In 12 interleaved single-thread measurements on ordinary complex values,
abs()took about 1.26x andsign()1.22x the baseline time; this change trades that overhead for correct range handling.