Add getNbModalities function in MNIST

include/aidge/backend/opencv/database/MNIST.hpp

@@ -37,7 +37,6 @@ inline bool isBigEndian()
 
 class MNIST : public Database {
 public:
-    MNIST() = delete;
     MNIST(const std::string& dataPath, 
             // const GraphView transformations, 
             bool train,
@@ -65,6 +64,8 @@ public:
 
     std::size_t getLen() override;
 
+    std::size_t getNbModalities() override;
+
     union MagicNumber {
         unsigned int value;
         unsigned char byte[4];

src/database/MNIST.cpp

@@ -127,7 +127,7 @@ void Aidge::MNIST::uncompress(const std::string& dataPath,
 std::vector<std::shared_ptr<Aidge::Tensor>> Aidge::MNIST::getItem(std::size_t index) {
     std::vector<std::shared_ptr<Tensor>> item;
     // Load the digit tensor 
-    // TODO : Currently converts the tensor Opencv but this operation will be carried by a convert operator later
+    // TODO : Currently converts the tensor Opencv but this operation will be carried by a convert operator in the preprocessing graph
     item.push_back(Aidge::convertCpu((std::get<0>(mStimulis.at(index))).load()));
     // item.push_back((std::get<0>(mStimulis.at(index))).load());
     // Load the label tensor 
@@ -138,4 +138,9 @@ std::vector<std::shared_ptr<Aidge::Tensor>> Aidge::MNIST::getItem(std::size_t in
 
 std::size_t  Aidge::MNIST::getLen(){
     return mStimulis.size();
+}
+
+std::size_t  Aidge::MNIST::getNbModalities(){
+    size_t tupleSize = std::tuple_size<decltype(mStimulis)::value_type>::value;
+    return tupleSize;
 }
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