As far as a computer is concerned, those numbers are "around" zero - "growing-up" w/ Matlab, e.g., one quickly learns to recognize these numbers for what they are. One way to return zero for numbers like these is
if numpy.allclose(x, 0): return 0 (or 0*x to assure that 0 is the same type as x), but caveat emptor: sometimes, of course, 1e-16 really is supposed to be 1e-16, not just the best the algorithm can do to get to zero. Also, (help me out here guys) I thought there was something like zeroifclose(x) which does the above, or does numpy only have realifclose to return a real when an imaginary part is close to zero? DG WolfgangZillig wrote: > Hi, > > I'm quite new to numpy/scipy so please excuse if my problem is too obvious. > > example code: > > import numpy as n > print n.sin(n.pi) > print n.cos(n.pi/2.0) > > results in: > 1.22460635382e-016 > 6.12303176911e-017 > > I've expected something around 0. Can anybody explain what I am doing > wrong here? > > _______________________________________________ > Numpy-discussion mailing list > Numpy-discussion@scipy.org > http://projects.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
