[SciPy-Dev] Sylvester equation solver for complex matrices

Nils Wagner nwagner@iam.uni-stuttgart...
Sat Feb 11 04:45:02 CST 2012


Hi all,

I run a short test on the recent solver for Sylvester 
equations.
In case of complex input matrices the method returns
  ** On entry to ZTRSYL parameter number  2 had an illegal 
value

Nils


import numpy as np
from scipy import linalg as la
np.random.seed(10)
a = np.random.rand(20,20)+1j*np.random.rand(20,20)
b = np.random.rand(20,20)+1j*np.random.rand(20,20)
q = np.random.rand(20,20)+1j*np.random.rand(20,20)

x = la.solve_sylvester(a,b,q)
res = la.norm(np.dot(a,x)+np.dot(x,b)-q)


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