Support of the YOLOv3

Description

This merge request introduces 2 changes, required for the support of the PTQ of the YOLOv3.

The first one consists in replacing all the float computations by their double counterpart. This choice is motivated by the fact that the computations of the ranges of the activations, done after the normalization of the parameters, lead to value overflows. This change now imposes a cast of the network in double precision before the PTQ, that is reverted back to the original type afterwards. This design choice may be re-examined later.

The second one is a small fix, that allows multiple outputs architectures to be properly handled.

Files changed

All the PTQ files are affected by the replacement of floats to doubles. The QAT files remain untouched.