diff options
Diffstat (limited to 'numpy/core/getlimits.py')
| -rw-r--r-- | numpy/core/getlimits.py | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/numpy/core/getlimits.py b/numpy/core/getlimits.py index e2ff49393..f73c21f67 100644 --- a/numpy/core/getlimits.py +++ b/numpy/core/getlimits.py @@ -337,8 +337,8 @@ class finfo: The approximate decimal resolution of this type, i.e., ``10**-precision``. tiny : float - The smallest positive usable number. Type of `tiny` is an - appropriate floating point type. + The smallest positive floating point number with full precision + (see Notes). Parameters ---------- @@ -359,6 +359,18 @@ class finfo: impacts import times. These objects are cached, so calling ``finfo()`` repeatedly inside your functions is not a problem. + Note that ``tiny`` is not actually the smallest positive representable + value in a NumPy floating point type. As in the IEEE-754 standard [1]_, + NumPy floating point types make use of subnormal numbers to fill the + gap between 0 and ``tiny``. However, subnormal numbers may have + significantly reduced precision [2]_. + + References + ---------- + .. [1] IEEE Standard for Floating-Point Arithmetic, IEEE Std 754-2008, + pp.1-70, 2008, http://www.doi.org/10.1109/IEEESTD.2008.4610935 + .. [2] Wikipedia, "Denormal Numbers", + https://en.wikipedia.org/wiki/Denormal_number """ _finfo_cache = {} @@ -546,4 +558,3 @@ class iinfo: def __repr__(self): return "%s(min=%s, max=%s, dtype=%s)" % (self.__class__.__name__, self.min, self.max, self.dtype) - |