[CppAD] numpy eigenvalues in pyCppAD

[Jyotiranjan Beuria]

Dear Experts,

I am trying to use python wrapper for CppAD. My function
depends on the eigenvalues of a matrix. Can anyone help
me in this regard. The code is given below.

*************************************************************
from pycppad import *
import numpy as np
def Pot(arg):
      x=independent(arg)
      m00=x[0]*x[0]
      m11=x[1]*x[1]
      m01=x[0]*x[1]
      m10=-x[0]*x[1]
      m=np.array([[m00,m01],[m10,m11]])
      return np.array([np.sum(np.linalg.eigvalsh(m))],dtype='a2float')
def hessian():
  delta = 10. * np.finfo(float).eps
  x     = np.array( [ 0., 0. ] )
  a_x   = independent(x)
  a_y   = Pot(a_x)
  f   = adfun(a_x, a_y)
  x   = np.array( [ 2., 3. ] )
  H   = f.hessian(x, [0])
  print H

hessian()
*************************************************************

I am getting following error.











*Traceback (most recent call last):  File "hessian2.py", line 37, in
<module>    pycppad_test_hessian()  File "hessian2.py", line 30, in
pycppad_test_hessian    a_y   = Pot(a_x)  File "hessian2.py", line 24, in
Pot    return np.array([np.sum(np.linalg.eigvalsh(m))],dtype='a2float')
File "/usr/local/lib/python2.7/dist-packages/numpy/linalg/linalg.py", line
994, in eigvalsh    w = gufunc(a, signature=signature,
extobj=extobj)TypeError: No loop matching the specified signature and
castingwas found for ufunc eigvalsh_lo*

Regards,
Jyotiranjan Beuria
Graduate student, HRI, INDIA
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