'Newbie question'

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List: python-list
Subject: Newbie question
From: Joe Hays <joey_hays () hotmail ! com>
Date: 2008-11-06 21:14:08
Message-ID: BAY136-W533CCEA8B2E06E09ACE6178A1E0 () phx ! gbl
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I'm a newbie to python. Can anyone tell me why the following little program complains \
about incorrect dimensions?

<snip>
import pylab
from pylab import *

n = 10; m = 2*n;
A = randn(m,n);
b = A*rand(n,1) + 2*rand(m,1);
</snip>

The actual error I receive is,

<snip>
b = A*rand(n,1) + 2*rand(m,1);
ValueError: shape mismatch: objects cannot be broadcast to a single shape
</snip>

This is supposed to be doing a matrix multply of an (m,n)(n,1). This results in an \
(m,1). This should then be able to be added to the 2*rand(m,1), but, its not for some \
reason.

Ideas?

Joe

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I'm a newbie to python. Can anyone tell me why the following little program complains \
about incorrect dimensions? &lt;snip&gt; <blockquote>import pylab from \
pylab import * n = 10; m = 2*n; A = randn(m,n); b = A*rand(n,1) + \
2*rand(m,1); </blockquote>&lt;/snip&gt; The actual error I receive \
is, &lt;snip&gt; <blockquote>b = A*rand(n,1) + 2*rand(m,1); ValueError: \
shape mismatch: objects cannot be broadcast to a single \
shape </blockquote>&lt;/snip&gt; This is supposed to be doing a matrix \
multply of an (m,n)(n,1). This results in an (m,1). This should then be able to be \
added to the 2*rand(m,1), but, its not for some \
reason. Ideas? Joe <hr />Windows Live Hotmail now works up \
to 70% faster. <a href='http://windowslive.com/Explore/Hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_faster_112008' \
target='_new'>Sign up today.</a></body> </html>

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