Re: [Numpy-discussion] Matrix operation.

2010-04-02 Thread Vicente Sole
With A and X being arrays: B=numpy.zeros(A.shape, A.dtype) B[A>0] = X Armando Quoting gerardob : > > Let A be a square matrix of 0's and 1's, and let X be a one dimesional > vector. > The length of X is equal to the number of 1's that A has. > I would like to produce a new matrix B by traversi

Re: [Numpy-discussion] Matrix operation.

2010-04-02 Thread Shailendra
>>> A=[[1,1,0], ... [1,0,0], ... [0,0,1]] >>> X=[2,9,10,3] >>> import numpy >>> A=numpy.asarray(A) >>> X=numpy.asarray(X) >>> A array([[1, 1, 0], [1, 0, 0], [0, 0, 1]]) >>> X array([ 2, 9, 10, 3]) >>> non_zero=numpy.nonzero(A) >>> non_zero (array([0, 0, 1, 2]), array([0, 1, 0, 2]))

[Numpy-discussion] Matrix operation.

2010-04-02 Thread gerardob
Let A be a square matrix of 0's and 1's, and let X be a one dimesional vector. The length of X is equal to the number of 1's that A has. I would like to produce a new matrix B by traversing the matrix A row by row and: 1- whenever i find a 0, set B in that position to zero. 2- whenever i find a 1,

Re: [Numpy-discussion] matrix operation

2010-03-17 Thread Christopher Barker
Christopher Barker wrote: > In [32]: numpy.minimum(A,B) wow! fifth to answer that one -- darn I'm slow! -Chris -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R(206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98

Re: [Numpy-discussion] matrix operation

2010-03-17 Thread Christopher Barker
gerardob wrote: > Let A and B be two n x n matrices. > > I would like to have another n x n matrix C such that > C_ij = min {A_ij, B_ij} In [30]: A = numpy.array([[2,3],[10,12]]) In [31]: B = numpy.array([[1,4],[9,13]]) In [32]: numpy.minimum(A,B) Out[32]: array([[ 1, 3], [ 9, 12]])

Re: [Numpy-discussion] matrix operation

2010-03-17 Thread Eric Firing
gerardob wrote: > Let A and B be two n x n matrices. > > I would like to have another n x n matrix C such that > C_ij = min {A_ij, B_ij} > > Example: > A = numpy.array([[2,3],[10,12]]) > B = numpy.array([[1,4],[9,13]]) > > Output > > C = [[1,3],[9,12]] > > The function min(axis) of numpy see

Re: [Numpy-discussion] matrix operation

2010-03-17 Thread Keith Goodman
On Wed, Mar 17, 2010 at 11:47 AM, gerardob wrote: > > Let A and B be two n x n matrices. > > I would like to have another n x n  matrix C such that > C_ij = min {A_ij, B_ij} > > Example: > A = numpy.array([[2,3],[10,12]]) > B = numpy.array([[1,4],[9,13]]) > > Output > > C = [[1,3],[9,12]] > > The

Re: [Numpy-discussion] matrix operation

2010-03-17 Thread Ernest Adrogué
17/03/10 @ 11:47 (-0700), thus spake gerardob: > > Let A and B be two n x n matrices. > > I would like to have another n x n matrix C such that > C_ij = min {A_ij, B_ij} > > Example: > A = numpy.array([[2,3],[10,12]]) > B = numpy.array([[1,4],[9,13]]) > > Output > > C = [[1,3],[9,12]] > > T

Re: [Numpy-discussion] matrix operation

2010-03-17 Thread Ian Mallett
>>> import numpy >>> A = numpy.array([[2,3],[10,12]]) >>> B = numpy.array([[1,4],[9,13]]) >>> C = numpy.array([A,B]) >>> numpy.min(C,0) array([[ 1, 3], [ 9, 12]]) Ian ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.

[Numpy-discussion] matrix operation

2010-03-17 Thread gerardob
Let A and B be two n x n matrices. I would like to have another n x n matrix C such that C_ij = min {A_ij, B_ij} Example: A = numpy.array([[2,3],[10,12]]) B = numpy.array([[1,4],[9,13]]) Output C = [[1,3],[9,12]] The function min(axis) of numpy seems to be only unary. Thanks. -- View thi

[Numpy-discussion] matrix operation.

2010-03-15 Thread gerardo.berbeglia
I have another matrix operations which seems a little more complicated. Let A be an n x n matrix and let S be a subset of {0,...,n-1}. Assume S is represented by a binary vector s, with a 1 at the index i if i is in S. (e.g. if S={0,3} then s = [1,0,0,1]) I re-post the question because the examp

Re: [Numpy-discussion] matrix operation

2010-03-12 Thread Robert Kern
On Fri, Mar 12, 2010 at 12:52, gerardo.berbeglia wrote: > > Hello, > > I want to "divide" an n x n (2-dimension) numpy array matrix A by a n > (1-dimension) array d as follows: > > Take n = 2. > Let A=   2 3 >           1 10 > and let d = [ 3 2 ] > Then i would like to have "A/d" = 2/3  3/3 >    

[Numpy-discussion] matrix operation

2010-03-12 Thread gerardo.berbeglia
Hello, I want to "divide" an n x n (2-dimension) numpy array matrix A by a n (1-dimension) array d as follows: Take n = 2. Let A= 2 3 1 10 and let d = [ 3 2 ] Then i would like to have "A/d" = 2/3 3/3 1/2 10/2 This is to avoid loops t