diff --git a/mat.h b/mat.h
index b750ba2..13b3fcc 100644
--- a/mat.h
+++ b/mat.h
@@ -57,7 +57,7 @@ public:
 	const bool operator==(const NRMat &rhs) const {return !(*this != rhs);};
 	inline int getcount() const {return count?*count:0;}
 	NRMat & operator=(const NRMat &rhs);  //assignment
-        void clear() {LA_traits<T>::clear((*this)[0],nn*mm);}; //zero out
+        void clear() {if(nn&&mm) LA_traits<T>::clear((*this)[0],nn*mm);}; //zero out
 	void randomize(const T &x); //fill with random numbers
 	NRMat & operator=(const T &a);    //assign a to diagonal
 	NRMat & operator|=(const NRMat &rhs); //assignment to a new copy