[CppAD] numpy eigenvalues in pyCppAD

[Jyotiranjan Beuria]

Even after removing "x=independent(arg)" in the function definition
also does not solve the problem. It seems that np.linalg.eigvalsh()
is not accepting a_float types. At this point I have a naive question,
are all linear algebra modules offered by numpy compatible with
CppAD?

I still get following error:

  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 casting

was found for ufunc eigvalsh_lo


On Fri, Aug 4, 2017 at 4:02 AM, Brad Bell <bradbell at seanet.com> wrote:

> It seems from the statement
>         a_y   = Pot(a_x)
> that the return value from Pot should be an a_float.
>
> Looking at the code for Pot(arg), it is not clear what the call to
> independent is doing,
> nor how two levels are AD are used here.
>
> This makes me think that
>         def Pot(arg) :
>                 x=independent(arg)
> should be replaced by
>         def Pot(x) :
> and
>         dtype='a2float'
> should be replaced by
>         dtype='a_float'
>
>
>
>
> On 08/03/2017 05:07 AM, Jyotiranjan Beuria wrote:
>
>> 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 casting
>> was found for ufunc eigvalsh_lo*
>>
>> Regards,
>> Jyotiranjan Beuria
>> Graduate student, HRI, INDIA
>>
>>
>>
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-- 
Jyotiranjan Beuria
Ph.D Student, HRI Allahabad
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