[NumPy-Tickets] [NumPy] #1996: sin(180) != 0
NumPy Trac
numpy-tickets@scipy....
Wed Dec 14 03:23:40 CST 2011
#1996: sin(180) != 0
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Reporter: ilshat | Owner: somebody
Type: defect | Status: closed
Priority: normal | Milestone: Unscheduled
Component: Other | Version: 1.3.0
Resolution: worksforme | Keywords: numpy.math sin
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Changes (by rkern):
* status: new => closed
* resolution: => worksforme
Comment:
This is the most precise answer. 0 would be a less precise answer. math.pi
is not exactly the irrational number pi, just 64-bit floating point
approximation to it. sin() does not know that you really intended the real
irrational number pi. It only knows that you pass it something that is
almost but not quite pi.
If you want to use degrees, try the sindg() function in scipy.special.
sindg(180 + 360*n) == 0 exactly for all integer n (at least up to a very
large n where precision issues become a problem).
In any case, the math module is not part of numpy. Please report issues
concerning it on the Python bug tracker.
--
Ticket URL: <http://projects.scipy.org/numpy/ticket/1996#comment:1>
NumPy <http://projects.scipy.org/numpy>
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