[Numpy-discussion] Bug with cumsum(dtype='f8')? (original) (raw)
Craig Loomis cloomis at astro.princeton.edu
Wed Jun 21 12:41:14 EDT 2006
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Not sure if this one has been addressed. There appears to be a problem with cumsum(dtype=), with reasonably small numbers. Both PPC
and x86 Macs.
========
import numpy
print "numpy version:", numpy.version
v = numpy.arange(10002) # 10001 is OK, larger is "worse" print "ok: ", v.cumsum() print "not ok: ", v.cumsum(dtype=numpy.float64) print "ok: ", numpy.arange(10002,dtype=numpy.float64).cumsum()
=========
ActivePython 2.4.3 Build 11 (ActiveState Software Inc.) based on Python 2.4.3 (#1, Apr 3 2006, 18:07:14) [GCC 4.0.1 (Apple Computer, Inc. build 5247)] on darwin Type "help", "copyright", "credits" or "license" for more information.
import numpy print "numpy version:", numpy.version numpy version: 0.9.9.2549 v = numpy.arange(10002) # 10001 is OK, larger is
"worse" print "ok: ", v.cumsum() ok: [ 0 1 3 ..., 49995000 50005000 50015001] print "not ok: ", v.cumsum(dtype=numpy.float64) not ok: [ 0.00000000e+00 1.00010000e+04 3.00000000e+00 ...,
4.99950000e+07 5.00050000e+07 0.00000000e+00] print "ok: ", numpy.arange(10002,dtype=numpy.float64).cumsum() ok: [ 0.00000000e+00 1.00000000e+00 3.00000000e+00 ...,
4.99950000e+07 5.00050000e+07 5.00150010e+07]
- craig
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