Re: [Numpy-discussion] numerical gradient, Jacobian, and Hessian

2014-04-23 Thread Neal Becker
alex wrote:

 On Mon, Apr 21, 2014 at 3:13 AM, Eelco Hoogendoorn
 hoogendoorn.ee...@gmail.com wrote:
 As far as I can tell, [Theano] is actually the only tensor/ndarray aware
 differentiator out there
 
 And AlgoPy, a tensor/ndarray aware arbitrary order automatic
 differentiator (https://pythonhosted.org/algopy/)

I noticed julia seems to have a package

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Re: [Numpy-discussion] numerical gradient, Jacobian, and Hessian

2014-04-21 Thread Eelco Hoogendoorn
I was going to suggest numdifftools; its a very capable package in my
experience. Indeed it would be nice to have it integrated into scipy.

Also, in case trying to calculate a numerical gradient is a case of 'the
math getting too bothersome' rather than no closed form gradient actually
existing: Theano may be your best bet; I have very good experiences with it
as well. As far as I can tell, it is actually the only tensor/ndarray aware
differentiator out there (maple and mathematica don't appear to support
this)


On Sun, Apr 20, 2014 at 4:55 PM, Alan G Isaac alan.is...@gmail.com wrote:

 Awhile back there were good signs that SciPy
 would end up with a `diff` module:
 https://github.com/scipy/scipy/issues/2035
 Is this still moving forward?

 It would certainly be nice for SciPy to have intuitive
 numerical gradients, Jacobians, and Hessians.  The last
 two are I think missing altogether.  The first exists
 as scipy.optimize.approx_fprime.

 `approx_fprime` seems to work fine, but I suggest it
 has the following drawbacks:
 - it is hard to find (e.g., try doing a Google search
on scipy gradient or scipy numerical gradient
 - related, it is in the wrong location (scipy.optimize)
 - the signature is odd: (x,f,dx) instead of (f,x,dx)
(This matters for ease of recall and for teaching.)

 In any case, as I understand it, the author's of numdifftools
 http://code.google.com/p/numdifftools/
 expressed willingness to have their code moved into SciPy.
 This seems like an excellent way forward.
 There was talk of making this a summer of code project,
 but that seems to have sputtered.

 Alan Isaac
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Re: [Numpy-discussion] numerical gradient, Jacobian, and Hessian

2014-04-21 Thread alex
On Mon, Apr 21, 2014 at 3:13 AM, Eelco Hoogendoorn
hoogendoorn.ee...@gmail.com wrote:
 As far as I can tell, [Theano] is actually the only tensor/ndarray aware 
 differentiator out there

And AlgoPy, a tensor/ndarray aware arbitrary order automatic
differentiator (https://pythonhosted.org/algopy/)
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[Numpy-discussion] numerical gradient, Jacobian, and Hessian

2014-04-20 Thread Alan G Isaac
Awhile back there were good signs that SciPy
would end up with a `diff` module:
https://github.com/scipy/scipy/issues/2035
Is this still moving forward?

It would certainly be nice for SciPy to have intuitive
numerical gradients, Jacobians, and Hessians.  The last
two are I think missing altogether.  The first exists
as scipy.optimize.approx_fprime.

`approx_fprime` seems to work fine, but I suggest it
has the following drawbacks:
- it is hard to find (e.g., try doing a Google search
   on scipy gradient or scipy numerical gradient
- related, it is in the wrong location (scipy.optimize)
- the signature is odd: (x,f,dx) instead of (f,x,dx)
   (This matters for ease of recall and for teaching.)

In any case, as I understand it, the author's of numdifftools
http://code.google.com/p/numdifftools/
expressed willingness to have their code moved into SciPy.
This seems like an excellent way forward.
There was talk of making this a summer of code project,
but that seems to have sputtered.

Alan Isaac
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