Added _OPENMP guards

aidge_export_cpp/kernels/convolution.hpp

@@ -48,7 +48,9 @@ void convolution_forward(
                     0, DILATED_KERNEL_HEIGHT);
         const int iy = (oy * STRIDE_Y) - PADDING_Y;
 
+#ifdef _OPENMP
 #pragma omp parallel for collapse(2)
+#endif
         for (int ox = 0; ox < OUTPUTS_WIDTH; ++ox) {
             for (int output = 0; output < NB_OUTPUTS; ++output) {
                 // moved to inner loop for collapsing -->
@@ -200,7 +202,9 @@ void convolution_depthwise_forward(
                     0, DILATED_KERNEL_HEIGHT);
         const int iy = (oy * STRIDE_Y) - PADDING_Y;
 
+#ifdef _OPENMP
 #pragma omp parallel for collapse(2)
+#endif
         for (int ox = 0; ox < OUTPUTS_WIDTH; ++ox) {
             for (int output = 0; output < NB_OUTPUTS; ++output) {
                 // moved to inner loop for collapsing -->

aidge_export_cpp/kernels/fullyconnected.hpp

@@ -28,6 +28,9 @@ void fullyconnected_forward (
     // It is only an issue if the FC was after a flatten layer.
     // Otherwise it is not an issue for the other FC because CHANNELS_WIDTH = CHANNELS_HEIGHT = 1
     // Solution: Add a system to check dataformat
+#ifdef _OPENMP
+#pragma omp parallel for
+#endif
     for (int och = 0; och < NB_OUTPUTS; och++) {
 
         Bias_T weightedSum = (biases) ? biases[och] : Bias_T(0);
@@ -45,7 +48,9 @@ void fullyconnected_forward (
     }
 /*
 Here the kernel to use with inputs in NHWC and weights in NHWC
+#ifdef _OPENMP
 #pragma omp parallel for
+#endif
     for (int och = 0; och < NB_OUTPUTS; och++) {
 
         Bias_T weightedSum = (biases) ? biases[och] : Bias_T(0);

aidge_export_cpp/kernels/leakyrelu.hpp

@@ -11,7 +11,9 @@ void leakyrelu_forward (
     Output_T* __restrict outputs,
     const float negative_slope)
 {
+#ifdef _OPENMP
 #pragma omp parallel for
+#endif
     for (int i = 0; i < NB_DATA; ++i) {
         if (inputs[i] >= 0) {
             outputs[i] = inputs[i];

aidge_export_cpp/kernels/pooling.hpp

@@ -36,7 +36,9 @@ void pooling_forward(
                     0, POOL_HEIGHT);
         const int iy = (oy * STRIDE_Y) - PADDING_Y;
 
+#ifdef _OPENMP
 #pragma omp parallel for collapse(2)
+#endif
         for (int ox = 0; ox < OUTPUTS_WIDTH; ++ox) {
             for (int output = 0; output < NB_OUTPUTS; ++output) {
                 // moved to inner loop for collapsing -->