[NumPy-Tickets] [NumPy] #1742: cholesky error ?

NumPy Trac numpy-tickets@scipy....
Fri Feb 11 13:05:20 CST 2011


#1742: cholesky error ?
--------------------------+-------------------------------------------------
 Reporter:  pcrs          |       Owner:  pv   
     Type:  defect        |      Status:  new  
 Priority:  normal        |   Milestone:  2.0.0
Component:  numpy.linalg  |     Version:  1.5.1
 Keywords:                |  
--------------------------+-------------------------------------------------
 from numpy import *
 from numpy.linalg import cholesky
 a=array([[1.0, 0.0],[0.0, 1.0]])
 k=0.3;
 b=dot(a,array([[cos(k), sin(k)],[-sin(k), cos(k)]]))
 cholesky(b)
 array([[ 0.97741316,  0.        ],
        [-0.30234932,  0.92947371]])
 dot(c,c.transpose())
 array([[ 0.95533649, -0.29552021],
        [-0.29552021,  0.95533649]])
 b
 array([[ 0.95533649,  0.29552021],
        [-0.29552021,  0.95533649]])
 Isn't dot(c,c.transpose()) not supposed to be equal to b? the sign of
 b[0,1] is sign inverted

-- 
Ticket URL: <http://projects.scipy.org/numpy/ticket/1742>
NumPy <http://projects.scipy.org/numpy>
My example project


More information about the NumPy-Tickets mailing list