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Diffstat (limited to 'Doc/library/math.rst')
| -rw-r--r-- | Doc/library/math.rst | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/Doc/library/math.rst b/Doc/library/math.rst index 0749367045d..bf7a00549fc 100644 --- a/Doc/library/math.rst +++ b/Doc/library/math.rst @@ -10,8 +10,8 @@ -------------- -This module provides access to the mathematical functions defined by the C -standard. +This module provides access to common mathematical functions and constants, +including those defined by the C standard. These functions cannot be used with complex numbers; use the functions of the same name from the :mod:`cmath` module if you require support for complex @@ -53,10 +53,13 @@ noted otherwise, all return values are floats. :func:`frexp(x) <frexp>` Mantissa and exponent of *x* :func:`isclose(a, b, rel_tol, abs_tol) <isclose>` Check if the values *a* and *b* are close to each other :func:`isfinite(x) <isfinite>` Check if *x* is neither an infinity nor a NaN +:func:`isnormal(x) <isnormal>` Check if *x* is a normal number +:func:`issubnormal(x) <issubnormal>` Check if *x* is a subnormal number :func:`isinf(x) <isinf>` Check if *x* is a positive or negative infinity :func:`isnan(x) <isnan>` Check if *x* is a NaN (not a number) :func:`ldexp(x, i) <ldexp>` ``x * (2**i)``, inverse of function :func:`frexp` :func:`nextafter(x, y, steps) <nextafter>` Floating-point value *steps* steps after *x* towards *y* +:func:`signbit(x) <signbit>` Check if *x* is a negative number :func:`ulp(x) <ulp>` Value of the least significant bit of *x* **Power, exponential and logarithmic functions** @@ -144,8 +147,7 @@ Number-theoretic functions .. function:: factorial(n) - Return *n* factorial as an integer. Raises :exc:`ValueError` if *n* is not integral or - is negative. + Return factorial of the nonnegative integer *n*. .. versionchanged:: 3.10 Floats with integral values (like ``5.0``) are no longer accepted. @@ -374,6 +376,24 @@ Floating point manipulation functions .. versionadded:: 3.2 +.. function:: isnormal(x) + + Return ``True`` if *x* is a normal number, that is a finite + nonzero number that is not a subnormal (see :func:`issubnormal`). + Return ``False`` otherwise. + + .. versionadded:: next + + +.. function:: issubnormal(x) + + Return ``True`` if *x* is a subnormal number, that is a finite + nonzero number with a magnitude smaller than :data:`sys.float_info.min`. + Return ``False`` otherwise. + + .. versionadded:: next + + .. function:: isinf(x) Return ``True`` if *x* is a positive or negative infinity, and @@ -412,6 +432,15 @@ Floating point manipulation functions Added the *steps* argument. +.. function:: signbit(x) + + Return ``True`` if the sign of *x* is negative and ``False`` otherwise. + + This is useful to detect the sign bit of zeroes, infinities and NaNs. + + .. versionadded:: next + + .. function:: ulp(x) Return the value of the least significant bit of the float *x*: @@ -775,7 +804,7 @@ Constants The mathematical constant *τ* = 6.283185..., to available precision. Tau is a circle constant equal to 2\ *π*, the ratio of a circle's circumference to its radius. To learn more about Tau, check out Vi Hart's video `Pi is (still) - Wrong <https://www.youtube.com/watch?v=jG7vhMMXagQ>`_, and start celebrating + Wrong <https://vimeo.com/147792667>`_, and start celebrating `Tau day <https://tauday.com/>`_ by eating twice as much pie! .. versionadded:: 3.6 |