better naming convention

theano/sandbox/scan_module/scan.py

@@ -319,12 +319,12 @@ def scan(fn,
     """
     # Note : see the internal documentation of the scan op for naming
     # conventions and all other details
-    us, xys_info, ws, T = scan_utils.canonical_arguments(sequences,
-                                                         outputs_info,
-                                                         non_sequences,
-                                                         go_backwards,
-                                                         n_steps)
-
+    rvals = scan_utils.canonical_arguments(sequences,
+                                           outputs_info,
+                                           non_sequences,
+                                           go_backwards,
+                                           n_steps)
+    inputs, states_and_outputs_info, parameters, T = rvals
     # If we provided a known number of steps ( before compilation)
     # and if that number is 1 or -1, then we can skip the Scan Op,
     # and just apply the inner function once
@@ -340,9 +340,9 @@ def scan(fn,
 
     if T_value in (1, -1):
         return one_step_scan(fn,
-                             us,
-                             xys_info,
-                             ws,
+                             inputs,
+                             states_and_outputs_info,
+                             parameters,
                              T_value,
                              truncate_gradient)
 
@@ -352,22 +352,23 @@ def scan(fn,
     # 2. Allocate memory for the states of scan.
     mintaps = []
     lengths = []
-    for xy in xys_info:
-        if xy.get('taps', None) == [-1]:
+    for arg_info in states_and_outputs_info:
+        if arg_info.get('taps', None) == [-1]:
             mintaps.append(1)
             lengths.append(scalar_shared(numpy.int64(0)))
-            xy['initial'] = scan_utils.expand(tensor.unbroadcast(
-                    tensor.shape_padfelt(xy['initial'], 0), T))
-        elif xy.get('taps', None):
-            if numpy.any(numpy.array(xy.get('taps', [])) > 0):
+            arg_info['initial'] = scan_utils.expand(tensor.unbroadcast(
+                    tensor.shape_padfelt(state['initial'], 0), T))
+        elif arg_info.get('taps', None):
+            if numpy.any(numpy.array(arg_info.get('taps', [])) > 0):
                 # Make sure we do not have requests for future values of a
                 # sequence we can not provide such values
                 raise ValueError('Can not use future taps of outputs',
-                                    init_out)
-            mintap = abs(numpy.min(xy['taps']))
+                                 arg_info)
+            mintap = abs(numpy.min(arg_info['taps']))
             lengths.append(scalar_shared(numpy.int64(0)))
             mintaps.append(mintap)
-            xy['initial'] = scan_utils.expand(xy['initial'][:mintap], T)
+            arg_info['initial'] = scan_utils.expand(
+                arg_info['initial'][:mintap], T)
         else:
             mintaps.append(0)
             lengths.append(scalar_shared(numpy.int64(0)))
@@ -375,34 +376,37 @@ def scan(fn,
     # 3. Generate arguments for the function passed to scan. This will
     # function will return the outputs that need to be computed at every
     # timesteps
-    us_slices = [u[t] for u in us]
-    xs_slices = []
-    for n, xy in enumerate(xys_info):
+    inputs_slices = [input[t] for input in inputs]
+    states_slices = []
+    for n, state in enumerate(states_and_outputs_info):
+        # Check if it is actually a state and not an output
         if mintaps[n] != 0:
-            for k in init_out['taps']:
-                xs_slices.append(
-                    xy['initial'][(t + mintaps[n] - k) % lengths[n]])
+            for k in state['taps']:
+                states_slices.append(
+                    state['initial'][(t + mintaps[n] - k) % lengths[n]])
 
     # 4. Construct outputs that are to be computed by the inner
     # function of scan
-    args = us_slices + xs_slices + ws
-    cond, xys_results, updates = scan_utils.get_updates_and_outputs(fn(*args))
+    args = inputs_slices + states_slices + parameters
+    cond, states_and_outputs, updates = \
+            scan_utils.get_updates_and_outputs(fn(*args))
     if cond is not None:
-        as_while = True
+        as_repeatUntil = True
     else:
-        as_while = False
+        as_repeatUntil = False
 
     # User is allowed to provide no information if it only behaves like a
     # map
-    if len(xys_outputs) != len(xys_info) and len(xys_info) == 0:
-        xys_info = [None] * len(xys_outputs)
+    if (len(states_and_outputs) != len(states_and_outputs_info) and
+        len(states_and_outputs_info) == 0):
+        states_and_outputs_info = [None] * len(states_and_outputs)
 
     # 5. Construct the scan op
     # 5.1 Construct list of shared variables with updates (those that
     # can be treated as states (i.e. of TensorType) and those that can not
     # (like Random States)
     rvals = rebuild_collect_shared(
-        xys_results + [cond],
+        states_and_outputs + [cond],
         updates=updates,
         rebuild_strict=True,
         copy_inputs_over=True,
@@ -411,80 +415,87 @@ def scan(fn,
     # extracting the arguments
     input_variables, cloned_outputs, other_rval = rvals
     clone_d, update_d, update_expr, shared_inputs = other_rval
-    additional_xs_outer = []
-    additional_xs_inner = []
-    additional_xs_results = []
+    additional_input_states_outer = []
+    additional_input_states_inner = []
+    additional_output_states = []
     additional_lengths = []
-    zs_outer = []
-    zs_inner = []
-    zs_results = []
+    non_numeric_input_states_outer = []
+    non_numeric_input_states_inner = []
+    non_numeric_output_states = []
 
     for sv in shared_inputs:
         if sv in update_d:
             if isinstance(sv, TensorType):
                 # We can treat it as a sit sot
-                nw_x = scan_utils.expand(
-                    tensor.unbroadcast(
-                        tensor.shape_padleft(sv, 0), actual_n_steps))
+                nw_state = scan_utils.expand(
+                    tensor.unbroadcast(tensor.shape_padleft(sv, 0), T))
                 additional_lengths.append(scalar_shared(numpy.int64(0)))
-                additional_xs_outer.append(nw_x)
-                additional_xs_inner.append(nw_x.type())
-                additional_xs_results.append(
+                additional_input_states_outer.append(nw_state)
+                additional_input_states_inner.append(nw_state.type())
+                additional_output_states.append(
                     scan_utils.clone(tensor.set_subtensor(
-                        nw_x[(t + 1) % additional_lengths[-1]],
+                        nw_state[(t + 1) % additional_lengths[-1]],
                         update_d[sv])))
             else:
-                zs_outer.append(sv)
-                zs_inner.append(sv.type())
-                zs_results.append(update_d[sv])
+                non_numeric_input_states_outer.append(sv)
+                non_numeric_input_states_inner.append(sv.type())
+                non_numeric_output_states.append(update_d[sv])
 
     # 5.2 Collect and order inputs of the inner function
-    xs_outer = []
-    xs_results = []
+    input_states_outer = []
+    output_states = []
 
-    ys_outer = []
-    ys_results = []
+    memory_buffers_for_outputs = []
+    outputs = []
 
     for n, mintap in enumerate(mintaps):
         if mintap != 0:
-            x = xys_info[n]['initial']
-            xs_outer.append(x)
-            xs_results.append(
-                tensor.set_subtensor(x[(t + 1) % lengths[n]],
-                                     xys_results[n]))
+            input_state = states_and_outputs_info[n]['initial']
+            input_states_outer.append(input_state)
+            output_states.append(
+                tensor.set_subtensor(input_state[(t + 1) % lengths[n]],
+                                     states_and_outputs[n]))
         else:
-            y = scan_utils.allocate_memory(T, xys_info[n], xys_results[n])
-            ys_outer.append(y)
-            ys_results.append(
-                tensor.set_subtensor(y[t % lengths[n]], xys_results[n])
+            output = scan_utils.allocate_memory(
+                T, states_and_outputs_info[n], states_and_outputs[n])
+            memory_buffers_for_outputs.append(output)
+            outputs.append(
+                tensor.set_subtensor(output[t % lengths[n]],
+                                     states_and_outputs[n])
     # 5.3 Construct the  scan op
 
 
-def one_step_scan(fn, us, xys_info, ws, T, truncate_gradient):
+def one_step_scan(fn,
+                  inputs,
+                  states_and_outputs_info,
+                  parameters,
+                  T,
+                  truncate_gradient):
     """
     This function is evaluated if `n_steps` evaluates to either 1 or -1.
     """
     # 1. Grab slices of sequences
-    us_slices = [u[0] for u in us]
+    inputs_slices = [input[0] for input in inputs]
 
     # 2. Grab slices of states
-    xs_slices = []
-    for n, x in enumerate(xys_info):
-        if x.get('taps', None) == [-1]:
-            xs_slices.append(x['initial'])
-        elif init_out.get('taps', None):
-            if numpy.any(numpy.array(init_out.get('taps', [])) > 0):
+    states_slices = []
+    for n, arg_info in enumerate(states_and_outputs_info):
+        if arg_info.get('taps', None) == [-1]:
+            states_slices.append(arg_info['initial'])
+        elif arg_info.get('taps', None):
+            if numpy.any(numpy.array(arg_info.get('taps', [])) > 0):
                 # Make sure we do not have requests for future values of a
                 # sequence we can not provide such values
                 raise ValueError('Can not use future taps of outputs',
-                                    init_out)
+                                    arg_info)
             # go through the taps
-            mintap = abs(numpy.min(init_out['taps']))
-            xs_slices.append(x['initial'][k+mintap])
+            mintap = abs(numpy.min(arg_info['taps']))
+            states_slices.append(arg_info['initial'][k+mintap])
 
     # Re-order args
-    args = (us_slices + xs_slices + non_seqs)
-    cond, xys_results, updates = scan_utils.get_updates_and_outputs(fn(*args))
+    args = (inputs_slices + states_slices + parameters)
+    cond, states_and_outputs, updates = \
+                scan_utils.get_updates_and_outputs(fn(*args))
 
     # We do not need to use the scan op anymore, so we can just return
     # the outputs and updates we have
@@ -492,9 +503,9 @@ def one_step_scan(fn, us, xys_info, ws, T, truncate_gradient):
         _logger.warning(('When the number of steps is fixed and equal '
                 'to 1, the provided stopping condition, ',
                 str(cond), ' is ignored'))
-    xys_results = [tensor.unbroadcast(
-        tensor.shape_padleft(xy_results), 0) for xy in xys]
-    if len(xys) == 1:
-        xys_results = xys_results[0]
+    states_and_outputs = [tensor.unbroadcast(
+        tensor.shape_padleft(arg), 0) for arg in states_and_outputs]
+    if len(states_and_outputs) == 1:
+        states_and_outputs = states_and_outputs[0]
 
-    return (xys_results, updates)
+    return (states_and_outputs, updates)

theano/sandbox/scan_module/scan_utils.py

@@ -183,20 +183,19 @@ def canonical_arguments(sequences,
     and that the different fields of of a dictionary are set to default
     value if the user has not provided any.
     """
-    us = to_list(sequences)
-    xys_info = to_list(outputs_info)
-    ws = [tensor.as_tensor_variable(x) for x in to_list(non_sequences)]
+    states_info = to_list(outputs_info)
+    parameters = [tensor.as_tensor_variable(x) for x in to_list(non_sequences)]
 
-    us = []
-    for u in to_list(sequences):
+    inputs = []
+    for input in to_list(sequences):
         if not isinstance(u, dict):
-            us.append(u)
-        elif u.get('taps', True) is None:
-            us.append(u)
-        elif u.get('taps', None):
-            mintap = numpy.min(u['taps'])
-            maxtap = numpy.max(u['taps'])
-            for k in u['taps']:
+            inputs.append(input)
+        elif input.get('taps', True) is None:
+            inputs.append(input)
+        elif input.get('taps', None):
+            mintap = numpy.min(input['taps'])
+            maxtap = numpy.max(input['taps'])
+            for k in input['taps']:
                 # We cut the sequence such that seq[i] to correspond to
                 # seq[i-k]
                 if maxtap < 0:
@@ -204,57 +203,57 @@ def canonical_arguments(sequences,
                 else:
                     offset = 0
                 if maxtap == mintap and maxtap != 0:
-                    nw_u = u['input'][:abs(maxtap)]
+                    nw_input = input['input'][:abs(maxtap)]
                 elif maxtap - k != 0:
-                    nw_u = u['input'][offset + k - mintap: -(maxtap - k)]
+                    nw_input = input['input'][offset + k - mintap: -(maxtap - k)]
                 else:
-                    nw_u = u['input'][offset + k - mintap:]
+                    nw_input = input['input'][offset + k - mintap:]
                 if go_backwards:
-                    nw_u = nw_u[::-1]
-                us.append(nw_u)
+                    nw_input = nw_input[::-1]
+                inputs.append(nw_input)
         else:
-            raise ValueError('Provided sequence makes no sense', str(u))
+            raise ValueError('Provided sequence makes no sense', str(input))
 
     # Since we've added all sequences now we need to level them up based on
     # n_steps or their different shapes
     if n_steps is None:
-        if len(us) == 0:
+        if len(inputs) == 0:
             # No information about the number of steps
             raise ValueError('You need to provide either at least '
                              'one sequence over which scan should loop '
                              'or a number of steps for scan to loop. '
                              'Neither of the two had been provided !')
-        T = us[0].shape[0]
-        for u in us[1:]:
-            T = tensor.minimum(T, u.shape[0])
+        T = inputs[0].shape[0]
+        for input in inputs[1:]:
+            T = tensor.minimum(T, input.shape[0])
     else:
         T = tensor.as_tensor(n_steps)
     # Level up sequences
-    us = [u[:T] for u in us]
+    inputs = [input[:T] for input in inputs]
 
     # wrap outputs info in a dictionary if they are not already in one
-    for i, xy in enumerate(xys_info):
-        if xy is not None and not isinstance(xy, dict):
-            xys_info[i] = dict(initial=xy, taps=[-1])
-        elif isinstance(xy, dict):
-            if not xy.get('initial', None) and xy.get('taps', None):
+    for i, state in enumerate(states_info):
+        if state is not None and not isinstance(state, dict):
+            states_info[i] = dict(initial=state, taps=[-1])
+        elif isinstance(state, dict):
+            if not state.get('initial', None) and state.get('taps', None):
                 raise ValueError(('If you are using slices of an output '
                                   'you need to provide a initial state '
-                                  'for it'), xy)
-            elif xy.get('initial', None) and not xy.get('taps', None):
+                                  'for it'), state)
+            elif state.get('initial', None) and not state.get('taps', None):
                 # ^ initial state but taps not provided
-                if 'taps' in xy:
+                if 'taps' in state:
                     # ^ explicitly provided a None for taps
                     _logger.warning('Output %s ( index %d) has a initial '
                             'state but taps is explicitly set to None ',
-                             getattr(outs_info[i]['initial'], 'name', 'None'),
+                             getattr(states_info[i]['initial'], 'name', 'None'),
                              i)
-                xys_info[i]['taps'] = [-1]
+                states_info[i]['taps'] = [-1]
         else:
             # if a None is provided as the output info we replace it
             # with an empty dict() to simplify handling
-            xys_info[i] = dict()
-    return seqs, outs_info, non_seqs, actual_n_steps
+            states_info[i] = dict()
+    return inputs, staess_info, parameters, T
 
 
 def infer_shape(outs, inputs, input_shapes):