Theano provides two functions (:func:`theano.pp` and
:func:`theano.printing.debugprint`) to print a graph to the terminal before or after
compilation. These two functions print expression graphs in different ways:
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@@ -203,8 +205,14 @@ Apply nodes, and which Ops are eating up your CPU cycles.
Tips:
* use the flags floatX=float32 to use float32 instead of float64 for the theano type matrix(),vector(),...(if you used dmatrix, dvector() they stay at float64).
* Check that in the profile mode that there is no Dot operation and you're multiplying two matrices of the same type. Dot should be optimized to dot22 when the inputs are matrices and of the same type. This can happen when using floatX=float32 and something in the graph makes one of the inputs float64.
* use the flags ``floatX=float32`` to use *float32* instead of *float64*
for the theano type matrix(),vector(),...(if you used dmatrix, dvector()
they stay at *float64*).
* Check that in the profile mode that there is no Dot operation and you're
multiplying two matrices of the same type. Dot should be optimized to
dot22 when the inputs are matrices and of the same type. This can happen
when using floatX=float32 and something in the graph makes one of the
inputs *float64*.
.. _faq_wraplinker:
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@@ -239,7 +247,7 @@ along with its position in the graph, the arguments to the ``perform`` or
Admittedly, this may be a huge amount of
output to read through if you are using big tensors... but you can choose to
put logic inside of the print_eval function that would, for example, only
put logic inside of the *print_eval* function that would, for example, only
print something out if a certain kind of Op was used, at a certain program
position, or if a particular value shows up in one of the inputs or outputs.
Use your imagination :)
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@@ -247,7 +255,7 @@ Use your imagination :)
.. TODO: documentation for link.WrapLinkerMany
This can be a really powerful debugging tool.
Note the call to ``fn`` inside the call to ``print_eval``; without it, the graph wouldn't get computed at all!
Note the call to *fn* inside the call to *print_eval*; without it, the graph wouldn't get computed at all!
How to Use pdb ?
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@@ -296,7 +304,7 @@ of the error. There's the script where the compiled function was called --
but if you're using (improperly parameterized) prebuilt modules, the error
might originate from ops in these modules, not this script. The last line
tells us about the Op that caused the exception. In this case it's a "mul"
involving Variables name "a" and "b". But suppose we instead had an
involving variables with names "a" and "b". But suppose we instead had an
intermediate result to which we hadn't given a name.
After learning a few things about the graph structure in Theano, we can use
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@@ -329,7 +337,7 @@ explore around the graph.
That graph is purely symbolic (no data, just symbols to manipulate it
abstractly). To get information about the actual parameters, you explore the
"thunks" objects, which bind the storage for the inputs (and outputs) with
"thunk" objects, which bind the storage for the inputs (and outputs) with
the function itself (a "thunk" is a concept related to closures). Here, to
get the current node's first input's shape, you'd therefore do "p
thunk.inputs[0][0].shape", which prints out "(3, 4)".
