Fixed automatic append of py_ports and var_ports (lava-nc#669)

* Fixed automatic append of py_ports and var_ports

Added a check to prevent re-appending the same PyPort or VarPort that is already in a process model's py_ports or var_ports list.

Adjusted CspRecvPort implementation to allocate numpy _result array once at initialization rather than on every update.

Adjusted PyRefPortVectorDense to allocate header numpy arrays the first time they are used, rather than every time a value is sent.

* Fixing flake formatting.

* Reverting change to preallocate _result

It seems that putting the result of the CspRecvPort.recv into a pre-allocated numpy _result leads to a hang due to shared memory between processes, specifically in cases where the user code grabs data from a Monitor. Reverting that change for now, though in the future it would be good to find a way to effectively preallocate to avoid memory allocations during every timestep.

* Cleanup.

* Fixing flake issue.

src/lava/magma/compiler/channels/pypychannel.py

@@ -280,7 +280,6 @@ def recv(self):
         result = self._array[self._idx].copy()
         self._idx = (self._idx + 1) % self._size
         self._ack.release()
-
         return result
 
     def join(self):

src/lava/magma/core/model/py/model.py

@@ -74,10 +74,9 @@ def __setattr__(self, key: str, value: ty.Any):
 
         """
         self.__dict__[key] = value
-        if isinstance(value, AbstractPyPort):
+        if isinstance(value, AbstractPyPort) and value not in self.py_ports:
             self.py_ports.append(value)
-            # Store all VarPorts for efficient RefPort -> VarPort handling
-            if isinstance(value, PyVarPort):
+            if isinstance(value, PyVarPort) and value not in self.var_ports:
                 self.var_ports.append(value)
 
     def start(self):

src/lava/magma/core/model/py/ports.py

@@ -699,13 +699,16 @@ def read(self) -> np.ndarray:
             The value of the referenced Var.
         """
         if self._csp_send_port and self._csp_recv_port:
-            header = np.ones(self._csp_send_port.shape) * VarPortCmd.GET
-            self._csp_send_port.send(header)
-
+            if not hasattr(self, 'get_header'):
+                self.get_header = (np.ones(self._csp_send_port.shape)
+                                   * VarPortCmd.GET)
+            self._csp_send_port.send(self.get_header)
             return self._transformer.transform(self._csp_recv_port.recv(),
                                                self._csp_recv_port)
-
-        return np.zeros(self._shape, self._d_type)
+        else:
+            if not hasattr(self, 'get_zeros'):
+                self.get_zeros = np.zeros(self._shape, self._d_type)
+            return self.get_zeros
 
     def write(self, data: np.ndarray):
         """Abstract method to write data to a VarPort to set the value of the
@@ -717,8 +720,10 @@ def write(self, data: np.ndarray):
             The data to send via _csp_send_port.
         """
         if self._csp_send_port:
-            header = np.ones(self._csp_send_port.shape) * VarPortCmd.SET
-            self._csp_send_port.send(header)
+            if not hasattr(self, 'set_header'):
+                self.set_header = (np.ones(self._csp_send_port.shape)
+                                   * VarPortCmd.SET)
+            self._csp_send_port.send(self.set_header)
             self._csp_send_port.send(data)