[Numpy-discussion] Does numpy.bincount support numpy.float128 type weights?

2016-11-30 Thread Wei, Huayi
Hi, There, Here is a sample code using `numpy.bincount` import numpy as np a = np.array([1.0, 2.0, 3.0], dtype=np.float128) b = np.array([1, 2, 0], dtype=np.int) c = np.bincount(b, weights=a) If run it, I get the following error report: > 1 c = np.bincount(b, weights=a)

Re: [Numpy-discussion] Does numpy.bincount support numpy.float128 type weights?

2016-11-30 Thread Nathan Goldbaum
I think this is a deficiency in the current implementation of bincount, which always casts the weights to float64. This WIP pull request should probably fix it: https://github.com/numpy/numpy/pull/7464 On Wed, Nov 30, 2016 at 3:54 PM, Wei, Huayi wrote: > Hi, There, > > Here is a sample code usi

Re: [Numpy-discussion] Does numpy.bincount support numpy.float128 type weights?

2016-11-30 Thread Julian Taylor
Also note that float128 is rarely what you want. It is not a quad precision value, it maps to C long double which is 80 bit on x86 and less on stuff like arm. On 30.11.2016 22:59, Nathan Goldbaum wrote: > I think this is a deficiency in the current implementation of bincount, > which always casts

Re: [Numpy-discussion] Does numpy.bincount support numpy.float128 type weights?

2016-11-30 Thread Sebastian Berg
Fist off, a word of caution. float128 depends on your system and maps to whatever longdouble is (IIRC) or may not even exist. So I hope you don't expect IEEE 128 bit floats, if you are unsure, maybe check `np.finfo`. If speed does not matter ``` res = np.zeros(np.max(b), dtype=np.longdouble) np.ad