[Numpy-discussion] ValueError: matrices are not aligned!!!

Happyman bahtiyor_zohidov at mail.ru
Wed Sep 18 14:11:42 EDT 2013


I am trying to solve linear Ax=b problem, but some error occurs in the process like: 
Traceback (most recent call last):
File "C:\Python27\Conjugate_Gradient.py", line 66, in <module>
x, iter_number = conjGrad(Av,A, x, b)
File "C:\Python27\Conjugate_Gradient.py", line 51, in conjGrad
u = Av(A,s)
File "C:\Python27\Conjugate_Gradient.py", line 41, in Av
return np.dot(A,v)
ValueError: matrices are not aligned
-----------------------------------------------  I put the code below to check it.

import numpy as np
import math
def Av(A,v):
     return np.dot(A,v)
def conjGrad(Av,A, x, b, tol=1.0e-9):
    n = len(x)
    r = b - Av(A,x)
    s = r.copy()
    for i in range(n):
         u = Av(A,s)
         alpha = np.dot(s,r)/np.dot(s,u)
         x = x + aplha*s
         r = b - Av(A,x)
         if (math.sqrt(np.dot(r,r))) < tol:
                     beta = - np.dot(r,u)/np.dot(s,u)
                     s = r + beta * s
    return x,i
if __name__ == '__main__':
     # Input values
     A = np.arange(32, dtype=float).reshape((4,8))
     x = np.zeros(8)
     b = np.array([2.5, 4.5, 6.5, 8.0])
     x, iter_number = conjGrad(Av,A, x, b) I would appreciate any solution to this problem... 
Thanks in advance
happy man
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