diff --git a/src_main/math/pimathmatrix.h b/src_main/math/pimathmatrix.h
index 09e6905c..43dab5d1 100644
--- a/src_main/math/pimathmatrix.h
+++ b/src_main/math/pimathmatrix.h
@@ -536,6 +536,23 @@ inline PIMathVector<Type> operator *(const PIMathMatrix<Type> & fm,
 	return tv;
 }
 
+
+/// Multiply vector {Rows} on matrix {Rows x Cols}, result is vector {Cols}
+template<typename Type>
+inline PIMathVector<Type> operator *(const PIMathVector<Type> & sv,
+									  const PIMathMatrix<Type> & fm) {
+	uint c = fm.cols(), r = fm.rows();
+	PIMathVector<Type> tv(c);
+	Type t;
+	for (uint j = 0; j < c; ++j) {
+		t = Type(0);
+		for (uint i = 0; i < r; ++i)
+			t += fm.element(i, j) * sv[i];
+		tv[j] = t;
+	}
+	return tv;
+}
+
 /// Multiply value(T) on matrix {Rows x Cols}, result is vector {Rows}
 template<typename Type>
 inline PIMathMatrix<Type> operator *(const Type & x, const PIMathMatrix<Type> & v) {