Make the wrt variable optionally be a pair containing a setter and a getter

[bayerj]

Currently, the signature of optimizers only allows the following:

def __init__(self, wrt, f, ...):
    # ...

However, in some cases, this can lead to problems with the GPU: e.g. theano does not guarantee that changing shared variables (e.g. retrieved with borrow=True) will actually change the real thing in the background.

I therefore suggest to add the following behaviour:

def __init__(self, wrt, f, ...):
    if isinstance(wrt, tuple):
       self._get_wrt, self._set_wrt = wrt
    else:
        # the old methods from below work for the array
        self._wrt = wrt

def _get_wrt(self): return self._wrt
def _set_wrt(self, val): self._wrt[:] = val

The downside is that we will lose some inplace operations. But I am not too sure whether that is actually the case.

[smagt]

thanks.

On Feb 27, 2012, at 21:50 , Justin Bayer wrote:

Currently, the signature of optimizers only allows the following:

def init(self, wrt, f, ...):
# ...

However, in some cases, this can lead to problems with the GPU: e.g. theano does not guarantee that changing shared variables (e.g. retrieved with borrow=True) will actually change the real thing in the background.

I therefore suggest to add the following behaviour:

def init(self, wrt, f, ...):
if isinstance(wrt, tuple):
self._get_wrt, self._set_wrt = wrt
else:
# the old methods from below work for the array
self._wrt = wrt

def _get_wrt(self): return self._wrt
def _set_wrt(self, val): self._wrt[:] = val

The downside is that we will lose some inplace operations. But I am not too sure whether that is actually the case.

---

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Patrick van der Smagt - DLR, Institute of Robotics and Mechatronics
P.O. Box 1116, 82230 Wessling, Germany - ph +49 8153 281152 - brml.de