norse.torch.module.lif_adex module

class norse.torch.module.lif_adex.LIFAdEx(p=LIFAdExParameters(adaptation_current=tensor(4), adaptation_spike=tensor(0.0200), delta_T=tensor(0.5000), tau_ada_inv=tensor(2.), tau_syn_inv=tensor(200.), tau_mem_inv=tensor(100.), v_leak=tensor(0.), v_th=tensor(1.), v_reset=tensor(0.), method='super', alpha=100.0), **kwargs)[source]

Bases: norse.torch.module.snn.SNN

A neuron layer that wraps a recurrent LIFAdExCell in time such that the layer keeps track of temporal sequences of spikes. After application, the layer returns a tuple containing

(spikes from all timesteps, state from the last timestep).

Example

>>> data = torch.zeros(10, 5, 2) # 10 timesteps, 5 batches, 2 neurons
>>> l = LIFAdExLayer(2, 4)
>>> l(data) # Returns tuple of (Tensor(10, 5, 4), LIFExState)
Parameters

  • p (LIFAdExParameters) – The neuron parameters as a torch Module, which allows the module to configure neuron parameters as optimizable.

  • dt (float) – Time step to use in integration. Defaults to 0.001.

Initializes internal Module state, shared by both nn.Module and ScriptModule.

initial_state(input_tensor)[source]
Return type

LIFAdExFeedForwardState

training: bool
class norse.torch.module.lif_adex.LIFAdExCell(p=LIFAdExParameters(adaptation_current=tensor(4), adaptation_spike=tensor(0.0200), delta_T=tensor(0.5000), tau_ada_inv=tensor(2.), tau_syn_inv=tensor(200.), tau_mem_inv=tensor(100.), v_leak=tensor(0.), v_th=tensor(1.), v_reset=tensor(0.), method='super', alpha=100.0), **kwargs)[source]

Bases: norse.torch.module.snn.SNNCell

Computes a single euler-integration step of a feed-forward exponential LIF neuron-model without recurrence, adapted from http://www.scholarpedia.org/article/Adaptive_exponential_integrate-and-fire_model. It takes as input the input current as generated by an arbitrary torch module or function. More specifically it implements one integration step of the following ODE

\[\begin{split}\begin{align*} \dot{v} &= 1/\tau_{\text{mem}} \left(v_{\text{leak}} - v + i + \Delta_T exp\left({{v - v_{\text{th}}} \over {\Delta_T}}\right)\right) \\ \dot{i} &= -1/\tau_{\text{syn}} i \\ \dot{a} &= 1/\tau_{\text{ada}} \left( a_{current} (V - v_{\text{leak}}) - a \right) \end{align*}\end{split}\]

together with the jump condition

\[z = \Theta(v - v_{\text{th}})\]

and transition equations

\[i = i + i_{\text{in}}\]

where \(i_{\text{in}}\) is meant to be the result of applying an arbitrary pytorch module (such as a convolution) to input spikes.

Parameters

Examples

>>> batch_size = 16
>>> lif_ex = LIFAdExCell()
>>> data = torch.randn(batch_size, 20, 30)
>>> output, s0 = lif_ex(data)

Initializes internal Module state, shared by both nn.Module and ScriptModule.

initial_state(x)[source]
Return type

LIFAdExFeedForwardState

training: bool
class norse.torch.module.lif_adex.LIFAdExRecurrent(input_size, hidden_size, p=LIFAdExParameters(adaptation_current=tensor(4), adaptation_spike=tensor(0.0200), delta_T=tensor(0.5000), tau_ada_inv=tensor(2.), tau_syn_inv=tensor(200.), tau_mem_inv=tensor(100.), v_leak=tensor(0.), v_th=tensor(1.), v_reset=tensor(0.), method='super', alpha=100.0), **kwargs)[source]

Bases: norse.torch.module.snn.SNNRecurrent

A neuron layer that wraps a recurrent LIFAdExRecurrentCell in time (with recurrence) such that the layer keeps track of temporal sequences of spikes. After application, the layer returns a tuple containing

(spikes from all timesteps, state from the last timestep).

Example

>>> data = torch.zeros(10, 5, 2) # 10 timesteps, 5 batches, 2 neurons
>>> l = LIFAdExRecurrent(2, 4)
>>> l(data) # Returns tuple of (Tensor(10, 5, 4), LIFAdExState)
Parameters

  • input_size (int) – The number of input neurons

  • hidden_size (int) – The number of hidden neurons

  • p (LIFAdExParameters) – The neuron parameters as a torch Module, which allows the module to configure neuron parameters as optimizable.

  • input_weights (torch.Tensor) – Weights used for input tensors. Defaults to a random matrix normalized to the number of hidden neurons.

  • recurrent_weights (torch.Tensor) – Weights used for input tensors. Defaults to a random matrix normalized to the number of hidden neurons.

  • autapses (bool) – Allow self-connections in the recurrence? Defaults to False. Will also remove autapses in custom recurrent weights, if set above.

  • dt (float) – Time step to use in integration. Defaults to 0.001.

Initializes internal Module state, shared by both nn.Module and ScriptModule.

initial_state(input_tensor)[source]
Return type

LIFAdExState

training: bool
class norse.torch.module.lif_adex.LIFAdExRecurrentCell(input_size, hidden_size, p=LIFAdExParameters(adaptation_current=tensor(4), adaptation_spike=tensor(0.0200), delta_T=tensor(0.5000), tau_ada_inv=tensor(2.), tau_syn_inv=tensor(200.), tau_mem_inv=tensor(100.), v_leak=tensor(0.), v_th=tensor(1.), v_reset=tensor(0.), method='super', alpha=100.0), **kwargs)[source]

Bases: norse.torch.module.snn.SNNRecurrentCell

Computes a single of euler-integration step of a recurrent adaptive exponential LIF neuron-model with recurrence, adapted from http://www.scholarpedia.org/article/Adaptive_exponential_integrate-and-fire_model. More specifically it implements one integration step of the following ODE

\[\begin{split}\begin{align*} \dot{v} &= 1/\tau_{\text{mem}} \left(v_{\text{leak}} - v + i + \Delta_T exp\left({{v - v_{\text{th}}} \over {\Delta_T}}\right)\right) \\ \dot{i} &= -1/\tau_{\text{syn}} i \\ \dot{a} &= 1/\tau_{\text{ada}} \left( a_{current} (V - v_{\text{leak}}) - a \right) \end{align*}\end{split}\]

together with the jump condition

\[z = \Theta(v - v_{\text{th}})\]

and transition equations

\[\begin{split}\begin{align*} v &= (1-z) v + z v_{\text{reset}} \\ i &= i + w_{\text{input}} z_{\text{in}} \\ i &= i + w_{\text{rec}} z_{\text{rec}} \end{align*}\end{split}\]

where \(z_{\text{rec}}\) and \(z_{\text{in}}\) are the recurrent and input spikes respectively.

Examples

>>> batch_size = 16
>>> lif = LIFAdExRecurrentCell(10, 20)
>>> input = torch.randn(batch_size, 10)
>>> output, s0 = lif(input)
Parameters

  • input_size (int) – Size of the input. Also known as the number of input features.

  • hidden_size (int) – Size of the hidden state. Also known as the number of input features.

  • p (LIFAdExParameters) – Parameters of the LIF neuron model.

  • input_weights (torch.Tensor) – Weights used for input tensors. Defaults to a random matrix normalized to the number of hidden neurons.

  • recurrent_weights (torch.Tensor) – Weights used for input tensors. Defaults to a random matrix normalized to the number of hidden neurons.

  • autapses (bool) – Allow self-connections in the recurrence? Defaults to False. Will also remove autapses in custom recurrent weights, if set above.

  • dt (float) – Time step to use.

Initializes internal Module state, shared by both nn.Module and ScriptModule.

initial_state(input_tensor)[source]
Return type

LIFAdExState

training: bool