feat : support for conv3D forward

Context

issue : #38 (closed), aidge#252 (closed)

Added :

• Conv3D
• ConvTranspose3D
• Pad3D
• PaddedConv3D
• PaddedConvTranspose3D

Enhancements

Conv1D & Conv2D backward functions have been optimized : indexing is now done by only incrementing the index counters without using multiplication.

Before

for (DimSize_t kX = 0; kX < kDim[0]; ++kX) {
    kOffsets[2] = kX * kStrides[2] + kOffsets[1];
    iDilKernelOffsets[0] = kX * dilation[0] * iStrides[2];

    // DOING STUFF ...........
}

After

iDilKernelOffsets[0] = 0;
kOffsets[2] = kOffsets[1];
for (DimSize_t kX = 0; kX < kDims[0]; ++kX,
               kOffsets[2] += kStrides[2],
               iDilKernelOffsets[0] += dilation[0] *
                                       iStrides[2]) {
    // DOING STUFF ...........
}

NOTE : This implies a bit of unconventionnal over-crowding the for loops. That is usually written as :

for (DimSize_t kX = 0; kX < kDims[0]; ++kX) {
    // DOING STUFF ...........
    kOffsets[2] += kStrides[2];
    iDilKernelOffsets[0] += dilation[0] * iStrides[2];
}

but since the the //DOING STUFF....... usually contains 3+ nested loops, this would quickly be un-readable. Hence I chose to use the 1st "overcrowded for loop" syntax.

include/aidge/backend/cpu/operator/ConvImpl.hpp

@@ -68,9 +68,34 @@ using ConvImpl2D_cpu = OperatorImpl_cpu<Conv2D_Op,
                                              void *,
                                              void *)>;
 
+using Conv3D_Op = Conv_Op<3>;
+using ConvImpl3D_cpu = OperatorImpl_cpu<Conv3D_Op,
+                                        void(const std::array<DimSize_t, 3> &,
+                                             const std::array<DimSize_t, 3> &,
+                                             const std::array<DimSize_t, 3> &,
+                                             const std::array<DimSize_t, 5> &,
+                                             const std::array<DimSize_t, 5> &,
+                                             const void *,
+                                             const void *,
+                                             const void *,
+                                             void *),
+                                        void(const std::array<DimSize_t, 3> &,
+                                             const std::array<DimSize_t, 3> &,
+                                             const std::array<DimSize_t, 3> &,
+                                             const std::array<DimSize_t, 5> &,
+                                             const std::array<DimSize_t, 5> &,
+                                             const void *,
+                                             const void *,
+                                             const void *,
+                                             void *,
+                                             void *,
+                                             void *)>;
+
 // Implementation entry point registration to Operator
 REGISTRAR(Conv1D_Op, "cpu", Aidge::ConvImpl1D_cpu::create);
 REGISTRAR(Conv2D_Op, "cpu", Aidge::ConvImpl2D_cpu::create);
+REGISTRAR(Conv3D_Op, "cpu", Aidge::ConvImpl3D_cpu::create);
+
 } // namespace Aidge
 
 #endif /* AIDGE_CPU_OPERATOR_CONVIMPL_H_ */