[Numpy-discussion] Scalar values with a matrix
Colin J. Williams
cjw at sympatico.ca
Mon Jan 1 19:51:02 EST 2007
What is the best way to treat scalar values from a matrix?
It seems that it's best to treat them as a simple Python values and not
to leave them wrapped up in the ndarray structure. I would welcome advice.
The problem is illustrated below.
Colin W.
# tMul.py
import numpy.core as _n
a= _n.arange(12).reshape((3, 4))
b= _n.arange(12).reshape((4, 3))
c= _n.dot(a, b)
print `c`
amat= _n.mat(a)
bmat= _n.mat(b)
cmat= amat*bmat
print cmat
print _n.dot(amat, _n.mat(5))
Output:
>>>
array([[ 42, 48, 54],
[114, 136, 158],
[186, 224, 262]])
[[ 42 48 54]
[114 136 158]
[186 224 262]]
Traceback (most recent call last):
File "<string>", line 74, in run_nodebug
File "C:\Documents and Settings\cjw\My
Documents\PyDev\PyMatrix\tMiul.py", line 11, in <module>
print _n.dot(amat, _n.mat(5))
ValueError: objects are not aligned
>>>
More information about the NumPy-Discussion
mailing list