Re: [Numpy-discussion] Lookup array

2011-10-11 Thread Andrey N. Sobolev
В Mon, 10 Oct 2011 11:20:08 -0400 Olivier Delalleau пишет: > > The following doesn't use numpy but seems to be about 20x faster: > > A_rows = {} > for i, row in enumerate(A): > A_rows[tuple(row)] = i > for i, row in enumerate(B): > C[i] = A_rows.get(tuple(row), -1) >

Re: [Numpy-discussion] Lookup array

2011-10-10 Thread Andrey N. Sobolev
В Mon, 10 Oct 2011 10:03:48 +0100 Bob Dowling пишет: > > On 10/10/11 09:53, Andrey N. Sobolev wrote: > > > I have 2 arrays - A with the dimensions of 1000x4 and B with the > > dimensions of 5000x4. B doesn't (hopefully) contain any rows that > > are not in A. I

[Numpy-discussion] Lookup array

2011-10-10 Thread Andrey N. Sobolev
Hi all, I have 2 arrays - A with the dimensions of 1000x4 and B with the dimensions of 5000x4. B doesn't (hopefully) contain any rows that are not in A. I need to create a lookup array C, the i-th value of which will be the index of B[i] in A. In the (very rare) case when B[i] is not in A C[i] sho

Re: [Numpy-discussion] Norm of array of vectors

2011-03-17 Thread Andrey N. Sobolev
Hi eat and Gary, Thanks a lot for your suggestions, I've tried them in my code and achieved similar speedup of ~270% for both of them. So I guess I'll stick to one of those. Regards, Andrey. > Hi, > > On Thu, Mar 17, 2011 at 10:44 AM, Andrey N. Sobolev >

[Numpy-discussion] Norm of array of vectors

2011-03-17 Thread Andrey N. Sobolev
Dear all, Sorry if that's a noob question, but anyway. I have several thousands of vectors stacked in 2d array. I'd like to get new array containing Euclidean norms of these vectors and get the vector with minimal norm. Is there more efficient way to do this than argmin(array([sqrt(dot(x,x)) fo