final fft ops take shape as input, interface passes input array shape + odd correction

theano/gpuarray/fft.py

@@ -38,7 +38,14 @@ class CuRFFTOp(Op):
                             broadcastable=[False] * (inp.type.ndim + 1),
                             context_name=inp.type.context_name)
 
-    def make_node(self, inp):
+    def make_node(self, inp, s=None):
+        # A shape parameter s can be provided as an input. For now this is used to
+        # manage odd transform sizes.
+        # Later this could be extended to handle padding and trunkation,
+        # following numpy's interface. However, cuFFT expects array that match
+        # the shape given to the plan, so padding will have to be done in the op.
+        # The effect of padding on gradients has yet to be investigated.
+
         if not scikits_cuda_available:
             raise RuntimeError("scikits.cuda is needed for CuFFTOp")
 
@@ -52,9 +59,16 @@ class CuRFFTOp(Op):
             basic_ops.as_gpuarray_variable(inp,
                                            basic_ops.infer_context_name(inp)))
 
+        # If no shape is provided as input, default to input data shape.
+        if s is None:
+            s = inp.shape[1:]
+        s = T.as_tensor_variable(s)
+
         assert inp.dtype == "float32"
+        assert s.ndim == 1
+        assert 'int' in s.dtype
 
-        return theano.Apply(self, [inp], [self.output_type(inp)()])
+        return theano.Apply(self, [inp, s], [self.output_type(inp)()])
 
     def make_thunk(self, node, storage_map, _, _2):
 
@@ -70,9 +84,13 @@ class CuRFFTOp(Op):
 
         def thunk():
             input_shape = inputs[0][0].shape
+            s = inputs[1][0]
+
+            # Since padding is not supported, assert s matches input shape.
+            assert (input_shape[1:] == s).all()
 
             # construct output shape
-            output_shape = list(input_shape)
+            output_shape = [input_shape[0]] + list(s)
             # DFT of real input is symmetric, no need to store
             # redundant coefficients
             output_shape[-1] = output_shape[-1] // 2 + 1
@@ -99,13 +117,15 @@ class CuRFFTOp(Op):
                 # only initialise plan if necessary
                 if plan[0] is None or plan_input_shape[0] != input_shape:
                     plan_input_shape[0] = input_shape
-                    plan[0] = fft.Plan(input_shape[1:], np.float32, np.complex64,
+                    plan[0] = fft.Plan(s, np.float32, np.complex64,
                                        batch=input_shape[0])
+
                 # Sync GPU variables before computation
                 input_pycuda.sync()
                 output_pycuda.sync()
 
                 fft.fft(input_pycuda, output_pycuda, plan[0])
+
                 # Sync results to ensure output contains completed computation
                 pycuda.driver.Context.synchronize()
 
@@ -117,15 +137,18 @@ class CuRFFTOp(Op):
 
     def grad(self, inputs, output_grads):
         gout, = output_grads
-        s = inputs[0].shape[1:]
-        is_odd = s[-1] % 2
+        s = inputs[1]
         # Divide the last dimension of the output gradients by 2, they are
         # double-counted by the real-IFFT due to symmetry, except the first
         # and last elements (for even transforms) which are unique.
         idx = [slice(None)] * (gout.ndim - 2) \
-                + [slice(1, (s[-1] // 2) + is_odd)] + [slice(None)]
-        gout = T.set_subtensor(gout[idx], gout[idx]*0.5) 
-        return [cuirfft_op(gout, is_odd)]
+            + [slice(1, (s[-1] // 2) + (s[-1] % 2))] + [slice(None)]
+        gout = T.set_subtensor(gout[idx], gout[idx] * 0.5)
+        return [cuirfft_op(gout, s), DisconnectedType()()]
+
+    def connection_pattern(self, node):
+        # Specificy that shape input parameter has no connection to graph and gradients.
+        return [[True], [False]]
 
 curfft_op = CuRFFTOp()
 
@@ -135,12 +158,19 @@ class CuIRFFTOp(Op):
     __props__ = ()
 
     def output_type(self, inp):
-        # add one extra dim for real/imag
+        # remove extra dim for real/imag
         return GpuArrayType(inp.dtype,
                             broadcastable=[False] * (inp.type.ndim - 1),
                             context_name=inp.type.context_name)
 
-    def make_node(self, inp, is_odd):
+    def make_node(self, inp, s=None):
+        # A shape parameter is expected as an input. For now this is used to
+        # manage odd transform sizes.
+        # Later this could be extended to handle padding and trunkation,
+        # following numpy's interface. However, cuFFT expects array that match
+        # the shape given to the plan, so padding will have to be done in the op.
+        # The effect of padding on gradients has yet to be investigated.
+
         if not scikits_cuda_available:
             raise RuntimeError("scikits.cuda is needed for CuIFFTOp")
 
@@ -153,12 +183,17 @@ class CuIRFFTOp(Op):
         inp = basic_ops.gpu_contiguous(
             basic_ops.as_gpuarray_variable(inp,
                                            basic_ops.infer_context_name(inp)))
-        is_odd = T.as_tensor_variable(is_odd)
+
+        # If no shape is provided as input, calculate shape assuming even real transform.
+        if s is None:
+            s = inp.shape[1:-1]
+            s = T.set_subtensor(s[-1], (s[-1] - 1) * 2)
+        s = T.as_tensor_variable(s)
 
         assert inp.dtype == "float32"
-        assert 'int' in is_odd.dtype
+        assert s.ndim == 1
 
-        return theano.Apply(self, [inp, is_odd], [self.output_type(inp)()])
+        return theano.Apply(self, [inp, s], [self.output_type(inp)()])
 
     def make_thunk(self, node, storage_map, _, _2):
 
@@ -174,14 +209,16 @@ class CuIRFFTOp(Op):
 
         def thunk():
             input_shape = inputs[0][0].shape
-            is_odd = inputs[1][0]
-            assert is_odd in (0, 1)
+            s = inputs[1][0]
+
+            # Since padding is not supported, assert that last dimension corresponds to
+            # input forward transform size.
+            assert (input_shape[1:-2] == s[:-1]).all()
+            assert ((input_shape[-2] - 1) * 2 + s[-1] % 2 == s[-1]).all()
 
             # construct output shape
             # chop off the extra length-2 dimension for real/imag
-            output_shape = list(input_shape[:-1])
-            # restore full signal length
-            output_shape[-1] = (output_shape[-1] - 1) * 2 + is_odd
+            output_shape = [input_shape[0]] + list(s)
             output_shape = tuple(output_shape)
 
             z = outputs[0]
@@ -202,8 +239,9 @@ class CuIRFFTOp(Op):
                 # only initialise plan if necessary
                 if plan[0] is None or plan_input_shape[0] != input_shape:
                     plan_input_shape[0] = input_shape
-                    plan[0] = fft.Plan(output_shape[1:], np.complex64, np.float32,
+                    plan[0] = fft.Plan(s, np.complex64, np.float32,
                                        batch=output_shape[0])
+
                 # Sync GPU variables before computation
                 input_pycuda.sync()
                 output_pycuda.sync()
@@ -224,21 +262,23 @@ class CuIRFFTOp(Op):
 
     def grad(self, inputs, output_grads):
         gout, = output_grads
-        s = gout.shape
-        gf = curfft_op(gout)
+        s = inputs[1]
+        gf = curfft_op(gout, s)
         # Multiply the last dimension of the gradient by 2, they represent
         # both positive and negative frequencies, except the first
         # and last elements (for even transforms) which are unique.
         idx = [slice(None)] * (gf.ndim - 2) \
             + [slice(1, (s[-1] // 2) + (s[-1] % 2))] + [slice(None)]
-        gf = T.set_subtensor(gf[idx], gf[idx]*2)
+        gf = T.set_subtensor(gf[idx], gf[idx] * 2)
         return [gf, DisconnectedType()()]
 
     def connection_pattern(self, node):
-        return [[True],[False]]
+        # Specificy that shape input parameter has no connection to graph and gradients.
+        return [[True], [False]]
 
 cuirfft_op = CuIRFFTOp()
 
+
 def curfft(inp, norm=None):
     """
     Performs the fast Fourier transform of a real-valued output on the GPU
@@ -269,14 +309,14 @@ def curfft(inp, norm=None):
 
     s = inp.shape[1:]
     cond_norm = _unitary(norm)
-    if cond_norm is None or cond_norm == "no_norm":
     scaling = 1
-    elif cond_norm == "ortho":
+    if cond_norm == "ortho":
         scaling = T.sqrt(s.prod().astype('float32'))
 
-    return curfft_op(inp) / scaling                                  
+    return curfft_op(inp, s) / scaling
+
 
-def cuirfft(inp, norm=None, is_odd=0):
+def cuirfft(inp, norm=None, is_odd=False):
     """
     Performs the real-valued output inverse Fourier Transform using the
     gpuarray backend.
@@ -294,31 +334,36 @@ def cuirfft(inp, norm=None, is_odd=0):
     ----------
     inp
         Array of float32 of size (m, ..., n//2+1, 2), containing m inputs
-        with n/2+1 non-trivial elements on the last dimension and real
+        with n//2+1 non-trivial elements on the last dimension and real
         and imaginary parts stored as separate arrays.
     norm : {None, 'ortho', 'no_norm'}
         Normalization of transform. Following numpy, default *None* normalizes
         only the inverse transform by n, 'ortho' yields the unitary transform
         (:math:`1/\sqrt n` forward and inverse). In addition, 'no_norm' leaves
         the transform unnormalized.
-        
+    is_odd : {True, False}
+        Set to True to get a real inverse transform output with an odd last dimension
+        of length (N-1)*2 + 1 for an input last dimension of length N.
     """
 
-    if is_odd != 0:
-        is_odd = 1
+    if is_odd not in (True, False):
+        raise ValueError("Invalid value %s for id_odd, must be True or False" % is_odd)
 
     s = inp.shape[1:-1]
-    s = T.set_subtensor(s[-1], (s[-1] - 1) * 2 + is_odd)
+    if is_odd:
+        s = T.set_subtensor(s[-1], (s[-1] - 1) * 2 + 1)
+    else:
+        s = T.set_subtensor(s[-1], (s[-1] - 1) * 2)
 
     cond_norm = _unitary(norm)
+    scaling = 1
     if cond_norm is None:
         scaling = s.prod().astype('float32')
-    if cond_norm == "ortho":
+    elif cond_norm == "ortho":
         scaling = T.sqrt(s.prod().astype('float32'))
-    if cond_norm == "no_norm":
-        scaling = 1
 
-    return cuirfft_op(inp, is_odd) / scaling
+    return cuirfft_op(inp, s) / scaling
+
 
 def _unitary(norm):
     if norm not in (None, "ortho", "no_norm"):

theano/gpuarray/tests/test_fft.py

@@ -25,14 +25,13 @@ if not pycuda_available:  # noqa
 import theano.gpuarray.cuda_fft
 
 # Transform sizes
-N = 16
+N = 64
 
 
 class TestFFT(unittest.TestCase):
 
     def test_1Dfft(self):
         inputs_val = np.random.random((1, N)).astype('float32')
-        inputs = theano.shared(inputs_val)
 
         x = T.matrix('x', dtype='float32')
         rfft = theano.gpuarray.fft.curfft(x)
@@ -63,7 +62,7 @@ class TestFFT(unittest.TestCase):
 
         def f_irfft(inp):
             return theano.gpuarray.fft.cuirfft(inp)
-        inputs_val = np.random.random((1, N//2+1, 2)).astype('float32')
+        inputs_val = np.random.random((1, N // 2 + 1, 2)).astype('float32')
         utt.verify_grad(f_irfft, [inputs_val], eps=eps)
 
     def test_rfft(self):
@@ -76,7 +75,7 @@ class TestFFT(unittest.TestCase):
         res_rfft_comp = (np.asarray(res_rfft[:, :, :, 0]) +
                          1j * np.asarray(res_rfft[:, :, :, 1]))
 
-        rfft_ref = numpy.fft.rfftn(inputs_val, axes=(1,2))
+        rfft_ref = numpy.fft.rfftn(inputs_val, axes=(1, 2))
 
         utt.assert_allclose(rfft_ref, res_rfft_comp, atol=1e-4, rtol=1e-4)
 
@@ -115,7 +114,7 @@ class TestFFT(unittest.TestCase):
         res_rfft_comp = (np.asarray(res_rfft[:, :, :, 0]) +
                          1j * np.asarray(res_rfft[:, :, :, 1]))
 
-        rfft_ref_ortho = numpy.fft.rfftn(inputs_val, axes=(1,2), norm='ortho')
+        rfft_ref_ortho = numpy.fft.rfftn(inputs_val, axes=(1, 2), norm='ortho')
 
         utt.assert_allclose(rfft_ref_ortho, res_rfft_comp,
                             atol=1e-4, rtol=1e-4)
@@ -127,7 +126,7 @@ class TestFFT(unittest.TestCase):
         res_rfft_comp = (np.asarray(res_rfft[:, :, :, 0]) +
                          1j * np.asarray(res_rfft[:, :, :, 1]))
 
-        utt.assert_allclose(rfft_ref_ortho * np.sqrt(N*N),
+        utt.assert_allclose(rfft_ref_ortho * np.sqrt(N * N),
                             res_rfft_comp, atol=1e-4, rtol=1e-4)
 
         # Inverse FFT inputs
@@ -140,7 +139,8 @@ class TestFFT(unittest.TestCase):
         f_irfft = theano.function([], irfft, mode=mode_with_gpu)
         res_irfft = f_irfft()
 
-        irfft_ref_ortho = numpy.fft.irfftn(inputs_ref, axes=(1,2), norm='ortho')
+        irfft_ref_ortho = numpy.fft.irfftn(
+            inputs_ref, axes=(1, 2), norm='ortho')
 
         utt.assert_allclose(irfft_ref_ortho,
                             res_irfft, atol=1e-4, rtol=1e-4)
@@ -150,7 +150,7 @@ class TestFFT(unittest.TestCase):
         f_irfft = theano.function([], irfft, mode=mode_with_gpu)
         res_irfft = f_irfft()
 
-        utt.assert_allclose(irfft_ref_ortho * np.sqrt(N*N),
+        utt.assert_allclose(irfft_ref_ortho * np.sqrt(N * N),
                             res_irfft, atol=1e-4, rtol=1e-4)
 
     def test_grad(self):
@@ -191,7 +191,7 @@ class TestFFT(unittest.TestCase):
         res_rfft_comp = (np.asarray(res_rfft[:, :, :, 0]) +
                          1j * np.asarray(res_rfft[:, :, :, 1]))
 
-        rfft_ref = numpy.fft.rfftn(inputs_val, s=(M,M), axes=(1,2))#, s=(M, M), axes=(1,2))
+        rfft_ref = numpy.fft.rfftn(inputs_val, s=(M, M), axes=(1, 2))
 
         utt.assert_allclose(rfft_ref, res_rfft_comp, atol=1e-4, rtol=1e-4)
 
@@ -202,7 +202,7 @@ class TestFFT(unittest.TestCase):
 
         utt.assert_allclose(inputs_val, np.asarray(res_ifft))
 
-        inputs_val = np.random.random((1, M, M//2+1, 2)).astype('float32')
+        inputs_val = np.random.random((1, M, M // 2 + 1, 2)).astype('float32')
         inputs = theano.shared(inputs_val)
 
         irfft = theano.gpuarray.fft.cuirfft(inputs, norm='ortho', is_odd=True)
@@ -210,7 +210,8 @@ class TestFFT(unittest.TestCase):
         res_irfft = f_irfft()
 
         inputs_ref = inputs_val[:, :, :, 0] + 1j * inputs_val[:, :, :, 1]
-        irfft_ref = numpy.fft.irfftn(inputs_ref, s=(M, M), axes=(1,2), norm='ortho')
+        irfft_ref = numpy.fft.irfftn(
+            inputs_ref, s=(M, M), axes=(1, 2), norm='ortho')
 
         utt.assert_allclose(irfft_ref, res_irfft, atol=1e-4, rtol=1e-4)
 
@@ -237,3 +238,16 @@ class TestFFT(unittest.TestCase):
             return theano.gpuarray.fft.cuirfft(inp, norm='no_norm', is_odd=True)
         inputs_val = np.random.random((1, M, M // 2 + 1, 2)).astype('float32')
         utt.verify_grad(f_irfft, [inputs_val], eps=eps)
+
+    def test_params(self):
+        inputs_val = np.random.random((1, N)).astype('float32')
+        inputs = theano.shared(inputs_val)
+        with self.assertRaises(ValueError):
+            theano.gpuarray.fft.curfft(inputs, norm=123)
+
+        inputs_val = np.random.random((1, N // 2 + 1, 2)).astype('float32')
+        inputs = theano.shared(inputs_val)
+        with self.assertRaises(ValueError):
+            theano.gpuarray.fft.cuirfft(inputs, norm=123)
+        with self.assertRaises(ValueError):
+            theano.gpuarray.fft.cuirfft(inputs, is_odd=123)