Signals

class nengo_dl.signals.TensorSignal(indices, key, dtype, shape, minibatched, label='TensorSignal')

Represents a tensor as an indexed view into a base array.

Parameters:

indices : tuple or list or ndarray of int

Indices along the first axis of the base array corresponding to the data for this signal

key : object

Key mapping to the base array that contains the data for this signal

dtype : dtype

dtype of the values represented by this signal

shape : tuple of int

View shape of this signal (may differ from shape of base array)

minibatched : bool

If True then this signal contains a minibatch dimension

label : str, optional

Name for this signal, used to make debugging easier

__getitem__(indices)

Create a new TensorSignal representing a subset (slice or advanced indexing) of the indices of this TensorSignal.

Parameters:

indices : slice or list of int

The desired subset of the indices in this TensorSignal

Returns:

:class:`.signals.TensorSignal`

A new TensorSignal representing the subset of this TensorSignal

reshape(shape)

Create a new TensorSignal representing a reshaped view of the same data in this TensorSignal (size of data must remain unchanged).

Parameters:

shape : tuple of int

New shape for the signal (one dimension can be -1 to indicate an inferred dimension size, as in numpy)

Returns:

:class:`.signals.TensorSignal`

New TensorSignal representing the same data as this signal but with the given shape

broadcast(axis, length)

Add a new dimension by broadcasting this signal along axis for the given length.

Parameters:

axis : 0 or -1

Where to insert the new dimension (currently only supports either the beginning or end of the array)

length : int

The number of times to duplicate signal along the broadcast dimension

Returns:

:class:`.signals.TensorSignal`

TensorSignal with new broadcasted shape

load_indices()

Loads the indices for this signal into TensorFlow, and if the indices form a contiguous slice then also loads the start/stop/step of that slice.

class nengo_dl.signals.SignalDict(sig_map, dtype, minibatch_size)

Handles the mapping from Signal to tf.Tensor.

Takes care of gather/scatter logic to read/write signals within the base arrays.

Parameters:

sig_map : dict of {Signal: TensorSignal}

Mapping from nengo signals to nengo_dl signals

dtype : tf.DType

Floating point precision used in signals

minibatch_size : int

Number of items in each minibatch

scatter(dst, val, mode='update')

Updates the base data corresponding to dst.

Parameters:

dst : TensorSignal

Signal indicating the data to be modified in base array

val : tf.Tensor

Update data (same shape as dst, i.e. a dense array <= the size of the base array)

mode : “update” or “inc”

Overwrite/add the data at dst with val

gather(src, force_copy=False)

Fetches the data corresponding to src from the base array.

Parameters:

src : TensorSignal

Signal indicating the data to be read from base array

force_copy : bool, optional

If True, always perform a gather, not a slice (this forces a copy). Note that setting force_copy=False does not guarantee that a copy won’t be performed.

Returns:

``tf.Tensor``

Tensor object corresponding to a dense subset of data from the base array

mark_gather(src)

Marks src as being gathered, but doesn’t actually perform a gather. Used to indicate that some computation relies on src.

Parameters:

src : TensorSignal

Signal indicating the data being read

combine(sigs, load_indices=True, label='Combine')

Combines several TensorSignals into one by concatenating along the first axis.

Parameters:

sigs : list of TensorSignal or Signal

Signals to be combined

load_indices : bool, optional

If True, load the indices for the new signal into TensorFlow right away (otherwise they will need to be manually loaded later)

label : str, optional

Name for combined signal (to help with debugging)

Returns:

:class:`.TensorSignal`

New TensorSignal representing the concatenation of the data in sigs