PSI sics-cvs-psi_pre-ansto

matrix/matmul.c

@@ -0,0 +1,57 @@
+/*
+*-----------------------------------------------------------------------------
+*	file:	matmul.c
+*	desc:	matrix multiplication
+*	by:	ko shu pui, patrick
+*	date:	24 nov 91 v0.1
+*	revi:
+*	ref:
+*       [1] Mary L.Boas, "Mathematical Methods in the Physical Sciene,"
+*	John Wiley & Sons, 2nd Ed., 1983. Chap 3.
+*
+*-----------------------------------------------------------------------------
+*/
+
+#include <stdio.h>
+#include "matrix.h"
+
+/*
+*-----------------------------------------------------------------------------
+*	funct:	mat_mul
+*	desct:	multiplication of two matrice
+*	given:	A, B = compatible matrice to be multiplied
+*	retrn:	NULL if malloc() fails
+*		else allocated matrix of A * B
+*	comen:
+*-----------------------------------------------------------------------------
+*/
+MATRIX mat_mul( A, B )
+MATRIX A, B;
+{
+	int	i, j, k;
+	MATRIX	C;
+
+	if ((C = mat_creat( MatRow(A), MatCol(B), UNDEFINED )) == NULL)
+		return (NULL);
+
+	for (i=0; i<MatRow(A); i++)
+	for (j=0; j<MatCol(B); j++)
+	for (k=0, C[i][j]=0.0; k<MatCol(A); k++)
+		{
+		C[i][j] += A[i][k] * B[k][j];
+		}
+	return (C);
+}
+
+double mat_diagmul( A )
+MATRIX A;
+{
+	int i;
+	double result = 1.0;
+
+	for (i=0; i<MatRow(A); i++)
+		{
+		result *= A[i][i];
+		}
+	return (result);
+}