On Wed, Sep 8, 2010 at 4:38 AM, John Reid <[email protected]>wrote:
> Hi, > > I recently upgraded to numpy 1.5.0 and now I get warnings when I take > the logarithm of 0. > > In [5]: np.log(0.) > Warning: divide by zero encountered in log > Out[5]: -inf > > > I want to evaluate x * log(x) where its value is defined as 0 when x=0 > so I have the following function: > > def safe_x_log_x(x): > "@return: x log(x) but replaces -inf with 0." > l = np.log(x) > result = x * l > result[np.isneginf(l)] = 0. > return result > > > Is there a better way of doing this that won't give me all these > warnings? Can I turn the warnings off? > > In [1]: log(0) Warning: divide by zero encountered in log Out[1]: -inf In [2]: olderr = np.seterr(divide='ignore') In [3]: log(0) Out[3]: -inf Chuck
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