Conv ProcessModels Ignore weight_exp Parameter

[Gavinator98]

Describe the bug
The conv process specifies a weight_exp parameter to scale the weights by a power of 2, similar to the dense process. The NcProcessModel (and seemingly all of the other Conv process models) do not utilize this weight_exp.

To reproduce current behavior

Specify a weight_exp

Conv(weight=np.ones((3, 1, 1, 3)), weight_exp=4)

Expected behavior
Weights are scaled by weight_exp when applied.

Environment (please complete the following information):

• Device: Intel Cloud
• OS: Linux
• Lava version 0.8.0
• Lava for Loihi version 0.5.0

[Gavinator98]

One alternative to having a weight_exp parameter in the Process could be to have the optimize_weight_bits take in floating point inputs and let it compute the weight_exp automatically. This line:

lava/src/lava/utils/weightutils.py

Line 80 in f7796e7

weights = weights.astype(np.int32) << int(-weight_exp)

would need to be changed to something like:

weights = np.round(weights * 2**(-weight_exp)).astype(np.int32)

to prevent the weights from being unnecessarily truncated.