Hi Norbert, Sorry, I don't believe I figured this out, and just went and implemented something else instead :/
Robin On Tue, May 22, 2018 at 2:21 AM, norbert <norbertryc...@gmail.com> wrote: > Hi Robin, > > I just came across the same issue.It looks very strange to me because I > was using this kind of code (scan in which some intermediate values of the > scan function have different sizes in different iterations) for a long time > and everything was OK, but after making small modyfications (putting > mentioned fragment into ifelse statement) it suddenly stopped working... > Have you figured out how to manage this issue and could you suggest a > solution? > > Norbert > > W dniu niedziela, 29 maja 2016 23:33:38 UTC+2 użytkownik > robi...@stanford.edu napisał: >> >> Hi, >> >> I'm getting an error computing gradients through a scan in which some >> intermediate values of the scan function have different sizes in different >> iterations (the inputs and outputs always have the same size). Here's a >> minimal example: >> >> import numpy as np >> import theano >> import theano.tensor as T >> >> d = 11 >> h = 7 >> W1 = theano.shared(name='W1', value=np.random.uniform(-0.1, 0.1, (d,h))) >> W2 = theano.shared(name='W2', value=np.random.uniform(-0.1, 0.1, (h,))) >> >> n = T.lscalar('n') >> vecs = T.matrix('vecs') >> inds = T.lmatrix('inds') >> def recurrence(t, vecs, inds, W1, W2): >> cur_inds = inds[T.eq(inds[:,0], t).nonzero()] >> cur_vecs = vecs[cur_inds[:,1]] >> hidden_layers = T.tanh(cur_vecs.dot(W1)) >> scores = hidden_layers.dot(W2) >> return T.sum(scores) >> results, _ = theano.scan( >> fn=recurrence, sequences=[T.arange(n)], outputs_info=[None], >> non_sequences=[vecs, inds, W1, W2], strict=True) >> obj = T.sum(results) >> grads = T.grad(obj, [W1, W2]) >> f = theano.function(inputs=[n, vecs, inds], outputs=grads) >> vecs_in = np.ones((10, d)) >> inds_in = np.array([[0, 0], [1, 1], [1, 2], [2, 3], [3, 4], [3, 5], [3, >> 6], [3, 7], [4, 8], [4, 9]]) >> print f(5, vecs_in, inds_in) >> >> >> Running this code results in the following error message (tried on 0.7.0, >> 0.8.2, and 0.9.0dev1.dev-0044349fdf4244c5b616994bf16ad2ff1ff8ce8a): >> >> Traceback (most recent call last): >> File "edge_scores.py", line 33, in <module> >> print f(5, vecs_in, inds_in) >> File >> "/usr/local/lib/python2.7/dist-packages/theano/compile/function_module.py", >> line 912, in __call__ >> storage_map=getattr(self.fn, 'storage_map', None)) >> File "/usr/local/lib/python2.7/dist-packages/theano/gof/link.py", line >> 314, in raise_with_op >> reraise(exc_type, exc_value, exc_trace) >> File >> "/usr/local/lib/python2.7/dist-packages/theano/compile/function_module.py", >> line 899, in __call__ >> self.fn() if output_subset is None else\ >> File >> "/usr/local/lib/python2.7/dist-packages/theano/scan_module/scan_op.py", >> line 951, in rval >> r = p(n, [x[0] for x in i], o) >> File >> "/usr/local/lib/python2.7/dist-packages/theano/scan_module/scan_op.py", >> line 940, in <lambda> >> self, node) >> File "theano/scan_module/scan_perform.pyx", line 547, in >> theano.scan_module.scan_perform.perform (/home/robinjia/.theano/compil >> edir_Linux-3.13--generic-x86_64-with-Ubuntu-14.04-trusty- >> x86_64-2.7.6-64/scan_perform/mod.cpp:6224) >> ValueError: could not broadcast input array from shape (11,4) into shape >> (11,2) >> Apply node that caused the error: forall_inplace,cpu,grad_of_scan_fn}(n, >> Alloc.0, Elemwise{eq,no_inplace}.0, Alloc.0, n, n, W1, W2, vecs, inds, >> InplaceDimShuffle{x,0}.0) >> Toposort index: 47 >> Inputs types: [TensorType(int64, scalar), TensorType(float64, col), >> TensorType(int8, matrix), TensorType(float64, matrix), TensorType(int64, >> scalar), TensorType(int64, scalar), TensorType(float64, matrix), >> TensorType(float64, vector), TensorType(float64, matrix), TensorType(int64, >> matrix), TensorType(float64, row)] >> Inputs shapes: [(), (5, 1), (5, 10), (2, 7), (), (), (11, 7), (7,), (10, >> 11), (10, 2), (1, 7)] >> Inputs strides: [(), (8, 8), (10, 1), (56, 8), (), (), (56, 8), (8,), >> (88, 8), (16, 8), (56, 8)] >> Inputs values: [array(5), array([[ 1.], >> [ 1.], >> [ 1.], >> [ 1.], >> [ 1.]]), 'not shown', 'not shown', array(5), array(5), 'not >> shown', 'not shown', 'not shown', 'not shown', 'not shown'] >> Outputs clients: [[Subtensor{int64}(forall_inplace,cpu,grad_of_scan_fn}.0, >> ScalarFromTensor.0)], [InplaceDimShuffle{1,0,2}(fora >> ll_inplace,cpu,grad_of_scan_fn}.1)], >> [Reshape{2}(forall_inplace,cpu,grad_of_scan_fn}.2, >> MakeVector{dtype='int64'}.0), Shape_i{1}(forall_inplace,cpu, >> grad_of_scan_fn}.2)]] >> >> HINT: Re-running with most Theano optimization disabled could give you a >> back-trace of when this node was created. This can be done with by setting >> the Theano flag 'optimizer=fast_compile'. If that does not work, Theano >> optimizations can be disabled with 'optimizer=None'. >> HINT: Use the Theano flag 'exception_verbosity=high' for a debugprint and >> storage map footprint of this apply node. >> >> >> A couple observations: >> - There's no error if I turn off optimizations (theano.config.optimizer = >> 'None') >> - There's no error if I have a single layer and no hidden layer (i.e. if >> scores = cur_vecs.dot(W) for W of the appropriate shape). >> >> Thanks! >> >> Robin >> > -- > > --- > You received this message because you are subscribed to a topic in the > Google Groups "theano-users" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/theano-users/zHMG2fMOA-I/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > theano-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- --- You received this message because you are subscribed to the Google Groups "theano-users" group. 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