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Diffstat (limited to 'Doc/library/math.rst')
| -rw-r--r-- | Doc/library/math.rst | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/Doc/library/math.rst b/Doc/library/math.rst index ecb1d4102ca..bf7a00549fc 100644 --- a/Doc/library/math.rst +++ b/Doc/library/math.rst @@ -59,6 +59,7 @@ noted otherwise, all return values are floats. :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** @@ -431,6 +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*: @@ -794,7 +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 |