94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#define N 2 // 矩阵大小
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void matrix_multiply(int A[][N], int B[][N], int C[][N])
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{
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int i, j, k;
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if (N == 1) {
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C[0][0] = A[0][0] * B[0][0];
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return;
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} else {
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int A11[N / 2][N / 2], A12[N / 2][N / 2], A21[N / 2][N / 2], A22[N / 2][N / 2];
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int B11[N / 2][N / 2], B12[N / 2][N / 2], B21[N / 2][N / 2], B22[N / 2][N / 2];
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int C11[N / 2][N / 2], C12[N / 2][N / 2], C21[N / 2][N / 2], C22[N / 2][N / 2];
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int P[N / 2][N / 2], Q[N / 2][N / 2], R[N / 2][N / 2], S[N / 2][N / 2],
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T[N / 2][N / 2], U[N / 2][N / 2], V[N / 2][N / 2];
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// 将矩阵分成4个小矩阵
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for (i = 0; i < N / 2; i++) {
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for (j = 0; j < N / 2; j++) {
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A11[i][j] = A[i][j];
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A12[i][j] = A[i][j + N / 2];
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A21[i][j] = A[i + N / 2][j];
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A22[i][j] = A[i + N / 2][j + N / 2];
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B11[i][j] = B[i][j];
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B12[i][j] = B[i][j + N / 2];
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B21[i][j] = B[i + N / 2][j];
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B22[i][j] = B[i + N / 2][j + N / 2];
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}
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}
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// 求7个小矩阵
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matrix_multiply(A11, B11, P);
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matrix_multiply(A12, B21, Q);
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matrix_multiply(A11, B12, R);
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matrix_multiply(A12, B22, S);
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matrix_multiply(A21, B11, T);
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matrix_multiply(A22, B21, U);
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matrix_multiply(A21, B12, V);
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// 根据公式计算四个子矩阵
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for (i = 0; i < N / 2; i++) {
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for (j = 0; j < N / 2; j++) {
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C11[i][j] = P[i][j] + Q[i][j];
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C12[i][j] = R[i][j] + S[i][j];
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C21[i][j] = T[i][j] + U[i][j];
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C22[i][j] = V[i][j] + P[i][j] - R[i][j] + T[i][j];
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}
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}
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// 将四个子矩阵合并成一个大矩阵
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for (i = 0; i < N / 2; i++) {
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for (j = 0; j < N / 2; j++) {
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C[i][j] = C11[i][j];
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C[i][j + N / 2] = C12[i][j];
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C[i + N / 2][j] = C21[i][j];
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C[i + N / 2][j + N / 2] = C22[i][j];
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}
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}
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}
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}
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int main()
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{
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int A[N][N] = {{1, 2}, {3, 4}};
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int B[N][N] = {{5, 6}, {7, 8}};
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int C[N][N];
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int i, j;
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matrix_multiply(A, B, C);
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printf("矩阵A:\n");
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for (i = 0; i < N; i++) {
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for (j = 0; j < N; j++) {
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printf("%d ", A[i][j]);
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}
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printf("\n");
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}
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printf("矩阵B:\n");
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for (i = 0; i < N; i++) {
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for (j = 0; j < N; j++) {
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printf("%d ", B[i][j]);
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}
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printf("\n");
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}
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printf("矩阵C:\n");
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for (i = 0; i < N; i++) {
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for (j = 0; j < N; j++) {
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printf("%d ", C[i][j]);
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}
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printf("\n");
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}
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return 0;
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} |