Add assert in fillers to avoid div by 0 or sqrt of neg.

src/filler/HeFiller.cpp

@@ -29,7 +29,9 @@ void Aidge::heFiller(std::shared_ptr<Aidge::Tensor> tensor,
               : (varianceNorm == Aidge::VarianceNorm::Average)
                   ? (fanIn + fanOut) / 2.0
                   : fanOut);
-
+    AIDGE_ASSERT(n > 0,
+                 "Something went wrong division by zero or square root of "
+                 "negative value.");
     const T stdDev(std::sqrt(2.0 / n));
 
     const T mean(varianceNorm == Aidge::VarianceNorm::FanIn ? meanNorm / fanIn

src/filler/XavierFiller.cpp

@@ -29,6 +29,9 @@ void Aidge::xavierUniformFiller(std::shared_ptr<Aidge::Tensor> tensor,
               : (varianceNorm == Aidge::VarianceNorm::Average)
                   ? (fanIn + fanOut) / 2.0
                   : fanOut);
+    AIDGE_ASSERT(n > 0,
+                 "Something went wrong division by zero or square root of "
+                 "negative value.");
     const T scale(std::sqrt(3.0 / n));
 
     std::uniform_real_distribution<T> uniformDist(-scale, scale);