Temporary remove fma in m2l product

experimental/include/scalfmm/utils/tensor.hpp

@@ -229,10 +229,10 @@ namespace scalfmm::tensor
             auto t_ = xsimd::load_aligned(&t.data()[i]);
             auto k_ = xsimd::load_aligned(&k.data()[i]);
             auto acc_ = xsimd::load_aligned(&accumulate.data()[i]);
-            auto times = k_*splat;
-            //acc_ += t_ * k_ * splat;
-            auto tmp = xsimd::fma(t_, times, acc_);
-            xsimd::store_aligned(&accumulate.data()[i], tmp);
+            //auto times = k_*splat;
+            //auto tmp = xsimd::fma(t_, times, acc_);
+            acc_ += t_ * k_ * splat;
+            xsimd::store_aligned(&accumulate.data()[i], acc_);
         }
         for(std::size_t i{vec_size}; i<size; ++i)
         {