Probably this can help you. Look in the manual about the ... operator, too. bash-2.02$ python Python 1.6b1 (#3, Aug 30 2000, 08:32:49) [GCC 2.7.2.1] on freebsd3 Copyright (c) Corporation for National Research Initiatives. Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam.
from Numeric import * a=array([[2,3],[4,5],[6,7]]) b=array([9,10,11]) a.shape (3, 2) b.shape (3,) print a+b[:,NewAxis] [[11 12] [14 15] [17 18]]
Jon Saenz. | Tfno: +34 946012470 Depto. Fisica Aplicada II | Fax: +34 944648500 Facultad de Ciencias. \\ Universidad del Pais Vasco \\ Apdo. 644 \\ 48080 - Bilbao \\ SPAIN On Mon, 19 Mar 2001, Aureli Soria Frisch wrote:
Hello!
I have a N-dimensional array A and I want to operate in one of the axis (k) with a 1 dimensional array (for instance, subtracting an array B of length k). I have looked for some solutions in the manual and did not found any.
So after testing a lot I found following solution:
A=Numeric.array(a)
A.shape=(a1,a2,...,ak,...,aN) #where N is any int value
B=Numeric.array(b) B.shape=(ak,)
A_modified=Numeric.reshape(A, (a1*a2*...*aN,ak)) #ak is not included in the product
result=[] for i in A_modified: result.append(i - B)
and finally reshaping the result appropriately. But it does not seem neither elegant nor simple.
Is there any more elegant solution? The key point is: how to operate a N-D array with a 1D in one determined axis?
Thanks in advance. Regards, Aureli
################################# Aureli Soria Frisch Fraunhofer IPK Dept. Pattern Recognition
post: Pascalstr. 8-9, 10587 Berlin, Germany e-mail:aureli@ipk.fhg.de fon: +49 30 39 00 61 50 fax: +49 30 39 17 517 #################################
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