diff --git a/include/trick/matrix_macros.h b/include/trick/matrix_macros.h
index 3e398591..52624888 100644
--- a/include/trick/matrix_macros.h
+++ b/include/trick/matrix_macros.h
@@ -300,4 +300,23 @@ Print matrix M to stderr.
    fprintf( stderr, "%f %f %f\n" , mat[2][0] , mat[2][1] , mat[2][2] ) ; \
 }
 
+/**
+@page MATRIX_MACROS Matrix Macros
+\b MxMxV(P, A, B, V)
+Assigns the product of A, B, and V to P.
+\f[
+p_i = \sum_{j=0}^{2} A_{i,j} \left( \sum_{k=0}^{2} B_{j,k} \cdot v_i \right) : i\in 0..2
+\f]
+*/
+#define MxMxV(prod, mat1, mat2, v ) { \
+  prod[0] = mat1[0][0] *(mat2[0][0] * vect[0] + mat2[0][1] * vect[1] + mat2[0][2] * vect[2])+\
+            mat1[0][1] *(mat2[1][0] * vect[0] + mat2[1][1] * vect[1] + mat2[1][2] * vect[2])+\
+            mat1[0][2] *(mat2[2][0] * vect[0] + mat2[2][1] * vect[1] + mat2[2][2] * vect[2]);\
+  prod[1] = mat1[1][0] *(mat2[0][0] * vect[0] + mat2[0][1] * vect[1] + mat2[0][2] * vect[2])+\
+            mat1[1][1] *(mat2[1][0] * vect[0] + mat2[1][1] * vect[1] + mat2[1][2] * vect[2])+\
+            mat1[1][2] *(mat2[2][0] * vect[0] + mat2[2][1] * vect[1] + mat2[2][2] * vect[2]);\
+  prod[2] = mat1[2][0] *(mat2[0][0] * vect[0] + mat2[0][1] * vect[1] + mat2[0][2] * vect[2])+\
+            mat1[2][1] *(mat2[1][0] * vect[0] + mat2[1][1] * vect[1] + mat2[1][2] * vect[2])+\
+            mat1[2][2] *(mat2[2][0] * vect[0] + mat2[2][1] * vect[1] + mat2[2][2] * vect[2]);\
+}
 #endif