Provisional fix of axis for softmax when importing from ONNX

src/serialization/onnx/net/layers/core/activation_onnx.cpp

@@ -202,11 +202,20 @@ Layer* build_softmax_layer(onnx::NodeProto *node,
   }
 
   int parent_dims = parent->output->getShape().size();
+
   if (axis < 0)                        // Check if the target axis is a negative index
     axis = parent_dims + axis;         // Get the target axis index
   if (axis < 0 || axis >= parent_dims) // Check for invalid axis index
     msg("The target axis for Softmax is not valid: axis = " + to_string(axis), "ONNX::ImportNet");
 
+  if (axis == 0  &&  parent_dims == 2)
+    axis = 1; // let us correct the problem of axis = 0 when importing a model in ONNX format where input shape does not contain the batch_size
+
+  if (axis == 0) { // Second check for invalid axis index
+    std::cerr << __FILE__ << "(" << __LINE__ << ")  axis = " << axis << "  shape.size = " << parent_dims << endl;
+    msg("The target axis for Softmax is not valid: axis = " + to_string(axis), "ONNX::ImportNet");
+  }
+
   return new LActivation(parent, "softmax", {static_cast<float>(axis)}, node->name(), dev, mem);
 }