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gh-135308: clarify math.issubnormal() description #135324

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gh-135308: clarify math.issubnormal() description #135324

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4 changes: 2 additions & 2 deletions Doc/library/math.rst
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Expand Up @@ -387,8 +387,8 @@ Floating point manipulation functions
.. function:: issubnormal(x)

Return ``True`` if *x* is a subnormal number, that is a finite
nonzero number with a magnitude smaller than the smallest positive normal
number, see :data:`sys.float_info.min`. Return ``False`` otherwise.
nonzero number with a magnitude smaller than :data:`sys.float_info.min`.
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The magnitude is an integer, it'll be smaller than sys.float_info.min if x is smaller than 1.

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nonzero number with a magnitude smaller than :data:`sys.float_info.min`.
nonzero number smaller than :data:`sys.float_info.min`.

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I guess the original meant “smaller than the magnitude of the smallest positive normal number”, but that's just extra words.

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This will be incorrect, as any finite negative floating-point number will satisfy your definition.

The magnitude is an integer

No. It's about absolute value of the float. See e.g. copysign() docs.

Return ``False`` otherwise.

.. versionadded:: next

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