我无法弄清楚为什么一个blas调用会引发错误。问题调用是最后一次调用。代码编译没有问题,运行正常,直到此调用失败,并显示以下消息。
** ACML错误:输入DGEMV参数编号6时出现非法值
据我所知,输入类型是正确的,数组a是正确的 我真的很感激能够深入了解这个问题。 感谢
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "cblas.h"
#include "array_alloc.h"
int main( void )
{
double **a, **A;
double *b, *B, *C;
int *ipiv;
int n, nrhs;
int info;
int i, j;
printf( "How big a matrix?\n" );
fscanf( stdin, "%i", &n );
/* Allocate the matrix and set it to random values but
with a big value on the diagonal. This makes sure we don't
accidentally get a singular matrix */
a = alloc_2d_double( n, n );
A= alloc_2d_double( n, n );
for( i = 0; i < n; i++ ){
for( j = 0; j < n; j++ ){
a[ i ][ j ] = ( ( double ) rand() ) / RAND_MAX;
}
a[ i ][ i ] = a[ i ][ i ] + n;
}
memcpy(A[0],a[0],n*n*sizeof(double)+1);
/* Allocate and initalise b */
b = alloc_1d_double( n );
B = alloc_1d_double( n );
C = alloc_1d_double( n );
for( i = 0; i < n; i++ ){
b[ i ] = 1;
}
cblas_dcopy(n,b,1,B,1);
/* the pivot array */
ipiv = alloc_1d_int( n );
/* Note we MUST pass pointers, so have to use a temporary var */
nrhs = 1;
/* Call the Fortran. We need one underscore on our system*/
dgesv_( &n, &nrhs, a[ 0 ], &n, ipiv, b, &n, &info );
/* Tell the world the results */
printf( "info = %i\n", info );
for( i = 0; i < n; i++ ){
printf( "%4i ", i );
printf( "%12.8f", b[ i ] );
printf( "\n" );
}
/* Want to check my lapack result with blas */
cblas_dgemv(CblasRowMajor,CblasTrans,n,n,1.0,A[0],1,B,1,0.0,C,1);
return 0;
}
答案 0 :(得分:3)
领先维度(LDA)至少需要与RowMajor矩阵的列数(n)一样大。你传递的LDA为1。
另外,我对你的矩阵类型有点怀疑;在没有看到如何实现alloc_2d_double
的情况下,无法确定是否正确布置矩阵。一般来说,使用BLAS样式矩阵(具有行或列步长的连续数组)混合指针到指针样式的“矩阵”是一种代码气味。 (但是,可能正确执行,您可能正确处理它;我们无法判断您发布的代码是否属于这种情况。)