Resfire (lava-nc#787)

* resfire process and fixed process model

* changed vth->uth in RFZero. Added tests.

* removed unused imports

* unused imports, copyright statement.

* bsd license on resfire models.py

src/lava/proc/resfire/models.py

@@ -0,0 +1,49 @@
+# Copyright (C) 2023 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause
+# See: https://spdx.org/licenses/
+
+
+import numpy as np
+from lava.proc.resfire.process import RFZero
+
+from lava.magma.core.sync.protocols.loihi_protocol import LoihiProtocol
+from lava.magma.core.model.py.ports import PyInPort, PyOutPort
+from lava.magma.core.model.py.type import LavaPyType
+from lava.magma.core.resources import CPU
+from lava.magma.core.decorator import implements, requires, tag
+from lava.magma.core.model.py.model import PyLoihiProcessModel
+
+
+@implements(proc=RFZero, protocol=LoihiProtocol)
+@requires(CPU)
+@tag('fixed_pt')
+class PyRFZeroModelFixed(PyLoihiProcessModel):
+    """Fixed point implementation of RFZero"""
+    u_in = LavaPyType(PyInPort.VEC_DENSE, np.int32, precision=24)
+    v_in = LavaPyType(PyInPort.VEC_DENSE, np.int32, precision=24)
+    s_out = LavaPyType(PyOutPort.VEC_DENSE, np.int32, precision=24)
+
+    uth: np.ndarray = LavaPyType(np.ndarray, np.int32, precision=24)
+
+    u: np.ndarray = LavaPyType(np.ndarray, np.int32, precision=24)
+    v: np.ndarray = LavaPyType(np.ndarray, np.int32, precision=24)
+
+    lst: np.ndarray = LavaPyType(np.ndarray, np.int32, precision=24)
+    lct: np.ndarray = LavaPyType(np.ndarray, np.int32, precision=24)
+
+    def run_spk(self) -> None:
+        u_in = self.u_in.recv()
+        v_in = self.v_in.recv()
+
+        new_u = ((self.u * self.lct) // (2**15)
+                 - (self.v * self.lst) // (2**15) + u_in)
+
+        new_v = ((self.v * self.lct) // (2**15)
+                 + (self.u * self.lst) // (2**15) + v_in)
+
+        s_out = new_u * (new_u > self.uth) * (new_v >= 0) * (self.v < 0)
+
+        self.u = new_u
+        self.v = new_v
+
+        self.s_out.send(s_out)

src/lava/proc/resfire/process.py

@@ -0,0 +1,65 @@
+# Copyright (C) 2022-23 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause
+# See: https://spdx.org/licenses/
+
+import numpy as np
+
+import typing as ty
+
+from lava.magma.core.process.process import AbstractProcess
+from lava.magma.core.process.variable import Var
+from lava.magma.core.process.ports.ports import InPort, OutPort
+
+
+class RFZero(AbstractProcess):
+    def __init__(self,
+                 shape: ty.Tuple[int, ...],
+                 freqs: np.ndarray,  # Hz
+                 decay_tau: np.ndarray,  # seconds
+                 dt: ty.Optional[float] = 0.001,  # seconds/timestep
+                 uth: ty.Optional[int] = 1) -> None:
+        """
+        RFZero
+        Resonate and fire neuron with spike trigger of threshold and
+        0-phase crossing. Graded spikes carry amplitude of oscillation.
+
+        Parameters
+        ----------
+        shape : tuple(int)
+            Number and topology of RF neurons.
+        freqs : numpy.ndarray
+            Frequency for each neuron (Hz).
+        decay_tau : numpy.ndarray
+            Decay time constant (s).
+        dt : float, optional
+            Time per timestep. Default is 0.001 seconds.
+        uth : float, optional
+            Neuron threshold voltage.
+            Currently, only a single threshold can be set for the entire
+            population of neurons.
+        """
+        super().__init__(shape=shape)
+
+        self.u_in = InPort(shape=shape)
+        self.v_in = InPort(shape=shape)
+
+        self.s_out = OutPort(shape=shape)
+
+        self.u = Var(shape=shape, init=0)
+        self.v = Var(shape=shape, init=0)
+
+        ll = -1 / decay_tau
+
+        lct = np.array(np.exp(dt * ll) * np.cos(dt * freqs * np.pi * 2))
+        lst = np.array(np.exp(dt * ll) * np.sin(dt * freqs * np.pi * 2))
+        lct = (lct * 2**15).astype(np.int32)
+        lst = (lst * 2**15).astype(np.int32)
+
+        self.lct = Var(shape=shape, init=lct)
+        self.lst = Var(shape=shape, init=lst)
+        self.uth = Var(shape=(1,), init=uth)
+
+    @property
+    def shape(self) -> ty.Tuple[int, ...]:
+        """Return shape of the Process."""
+        return self.proc_params['shape']

tests/lava/proc/resfire/test_resfire.py

@@ -0,0 +1,84 @@
+# Copyright (C) 2023 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause
+# See: https://spdx.org/licenses/
+
+import unittest
+import numpy as np
+
+from lava.proc.resfire.process import RFZero
+from lava.proc.dense.process import Dense
+from lava.proc import io
+
+from lava.magma.core.run_conditions import RunSteps
+from lava.magma.core.run_configs import Loihi2SimCfg
+
+
+class TestRFZeroProc(unittest.TestCase):
+    """Tests for RFZero"""
+
+    def test_rfzero_impulse(self):
+        """Tests for correct behavior of RFZero neurons from impulse input"""
+
+        num_steps = 50
+        num_neurons = 4
+        num_inputs = 1
+
+        # Create some weights
+        weightr = np.zeros((num_neurons, num_inputs))
+        weighti = np.zeros((num_neurons, num_inputs))
+
+        weightr[0, 0] = 50
+        weighti[0, 0] = -50
+
+        weightr[1, 0] = -70
+        weighti[1, 0] = -70
+
+        weightr[2, 0] = -90
+        weighti[2, 0] = 90
+
+        weightr[3, 0] = 110
+        weighti[3, 0] = 110
+
+        # Create inputs
+        inp_shape = (num_inputs,)
+        out_shape = (num_neurons,)
+
+        inp_data = np.zeros((inp_shape[0], num_steps))
+        inp_data[:, 3] = 10
+
+        # Create the procs
+        denser = Dense(weights=weightr, num_message_bits=24)
+        densei = Dense(weights=weighti, num_message_bits=24)
+
+        vec = RFZero(shape=out_shape, uth=1,
+                     decay_tau=0.1, freqs=20)
+
+        generator1 = io.source.RingBuffer(data=inp_data)
+        generator2 = io.source.RingBuffer(data=inp_data)
+        logger = io.sink.RingBuffer(shape=out_shape, buffer=num_steps)
+
+        # Connect the procs
+        generator1.s_out.connect(denser.s_in)
+        generator2.s_out.connect(densei.s_in)
+
+        denser.a_out.connect(vec.u_in)
+        densei.a_out.connect(vec.v_in)
+
+        vec.s_out.connect(logger.a_in)
+
+        # Run
+        try:
+            vec.run(condition=RunSteps(num_steps=num_steps),
+                    run_cfg=Loihi2SimCfg())
+            out_data = logger.data.get().astype(np.int32)
+        finally:
+            vec.stop()
+
+        expected_out = np.array([661, 833, 932, 1007])
+
+        self.assertTrue(
+            np.all(expected_out == out_data[[0, 1, 2, 3], [11, 23, 36, 48]]))
+
+
+if __name__ == '__main__':
+    unittest.main()