[Numpy-discussion] New ufuncs

Alan G Isaac aisaac@american....
Wed Nov 5 09:13:37 CST 2008


> Charles R Harris wrote:
>> Hmm... but I'm thinking one has to be clever here because the main
>> reason I heard for using logs was that normal floating point numbers
>> had insufficient range. So maybe something like
>>
>> logadd(a,b) = a + log(1 + exp(b - a))
>>
>> where a > b ?


On 11/5/2008 1:48 AM David Cournapeau apparently wrote:
> Yes, that's the idea. AFAIK, that's generally known as logsumexp
> algorithm, at least in the machine learning community, I opened a task
> ticket on it, but I have not done any work on it:
> 
> http://projects.scipy.org/scipy/numpy/ticket/765

Of possible relevance (BSD license):
http://code.google.com/p/pyspkrec/source/browse/pyspkrec/gmm.py?r=109
(Search on logsumexp.)
Alan Isaac



More information about the Numpy-discussion mailing list