lapack笔记：矩阵求逆

在有限元等参单元计算中，大量用到Jacobi矩阵的求逆。

这里给出一个使用lapack库函数求2x2矩阵逆的例子：

/**********************************************************
File: test_lapack.c
Author: Liang Zheng
E-mail: [email protected]
Date: 2014-6-19
**********************************************************/

#include <stdio.h>
#include <stdlib.h>

#include <lapacke.h>

int main()
{
  float a[2][2]float xx[]={23.0,54.0,67.0,2.0};
  lapack_int info;
  int n=2;
  lapack_int lda=2;
  lapack_int ipiv[2]={2,2};

  int i,j;
  info=LAPACKE_sgetrf(LAPACK_ROW_MAJOR,n,n,a,lda,ipiv);
  printf("info = %d\n",info);

  for(i=0;i<2;i++)
    for(j=0;j<2;j++)
      printf("a= %f\n",a[i][j]);

  for(i=0;i<2;i++)
    printf("ipiv = %d\n",ipiv[i]);

  info=LAPACKE_sgetri(LAPACK_ROW_MAJOR,n,a,lda,ipiv);
  printf("info = %d\n",info);

  for(i=0;i<2;i++)
    for(j=0;j<2;j++)
      printf("a= %f\n",a[i][j]);

  return 1;
}

lapack笔记：矩阵求逆