# [Numpy-discussion] objects are not aligned. Matrix and Array

Wayne Watson sierra_mtnview@sbcglobal....
Fri Dec 18 23:20:59 CST 2009

This program gives me the message following it:
================Program==========
import numpy as np
from numpy import matrix
import math

def sinD(D): # given in degrees, convert to radians
def cosD(D):

r = math.sqrt(2*2+5*5)
print r
m1 = matrix([[2], [5]])
print "m1: ", m1

theta = 5.0 # degrees
#CW 2x2 clockwise matrix
rotCW = matrix([ [cosD(theta), sinD(theta)], [-sinD(theta), cosD(theta)] ])

print rotCW

m2 = rotCW*m1
print "m2: ", m2
print "aaaaaaaa: ", type(m1), type(m2)
m1=np.array(m1)
m2=np.array(m2)

print "zzzzzzzz: ", type(m1), type(m2)

print"dot, ..."
dotres = np.dot(m1,m2)
print "dotres", dotres
==============end==========

==========Output msgs========
5.38516480713
m1:  [[2]
[5]]
[[ 0.9961947   0.08715574]
[-0.08715574  0.9961947 ]]
m2:  [[ 2.42816811]
[ 4.806662  ]]
aaaaaaaa:  <class 'numpy.core.defmatrix.matrix'> <class
'numpy.core.defmatrix.matrix'>
zzzzzzzz:  <type 'numpy.ndarray'> <type 'numpy.ndarray'>
dot, ...

Traceback (most recent call last):
File
line 30, in <module>
dotres = np.dot(m1,m2)
ValueError: objects are not aligned
================end msgs===========
Why the msg? The types look alike and each array/matrix contains two
elements..

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