More generic FuseMulAdd

src/recipes/FuseMulAdd.cpp

@@ -36,11 +36,37 @@ void Aidge::fuseMulAdd(std::shared_ptr<Aidge::Node> matmulNode, std::shared_ptr<
 
     // Step 1 : Create FC
     // Fetch the output dimension throught the bias size
-    std::shared_ptr<Node> bias = (addNode->getParent(1)) ? addNode->getParent(1)->cloneSharedOperators() : nullptr;
+    std::shared_ptr<Node> bias = nullptr;
+    if (addNode->getParent(0) == matmulNode) {
+        AIDGE_ASSERT(matmulNode->getParent(1), "No bias detected to produce the fuseMulAdd recipe.");
+        bias = addNode->getParent(1)->cloneSharedOperators();
+    }
+    else if (addNode->getParent(1) == matmulNode) {
+        AIDGE_ASSERT(matmulNode->getParent(0), "No bias detected to produce the fuseMulAdd recipe.");
+        bias = addNode->getParent(0)->cloneSharedOperators();
+    }
 
-    AIDGE_ASSERT(matmulNode->getParent(1), "No weight detected to produce the fuseMulAdd recipe.");
+    std::shared_ptr<Node> weight = nullptr;
+    if (matmulNode->getParent(1)->getOperator()->type() == Producer_Op::Type
+        && matmulNode->getParent(0)->getOperator()->type() != Producer_Op::Type)
+    {
+        weight = matmulNode->getParent(1)->cloneSharedOperators();
+    }
+    else if (matmulNode->getParent(0)->getOperator()->type() == Producer_Op::Type
+        && matmulNode->getParent(1)->getOperator()->type() != Producer_Op::Type)
+    {
+        weight = matmulNode->getParent(0)->cloneSharedOperators();
+    }
+    else if (matmulNode->getParent(0)->getOperator()->type() == Producer_Op::Type
+        && matmulNode->getParent(1)->getOperator()->type() == Producer_Op::Type)
+    {
+        // If both inputs are producers, there is an ambiguity, but both options
+        // result in a correct solution.
+        fmt::print("Warning: both MatMul inputs are Producers, assume data at input#0 and weights at input#1.\n");
+        weight = matmulNode->getParent(1)->cloneSharedOperators();
+    }
+    AIDGE_ASSERT(weight != nullptr, "Could not deduce weight input for MatMul operator.");
 
-    std::shared_ptr<Node> weight = matmulNode->getParent(1)->cloneSharedOperators();
     // TODO: find another way to get OutChannels for FC operator.
     // This poor fix supposes that one of Add inputs is a const and has the same outChannels as the output
     DimSize_t outSize = 0;