Question

我一直在努力实现MEX文件，我得到运行时错误！我想给出两个输入：inMatToInv，inMatToMul我想计算：inv（inMatToInv）* inMatToMul，我假设用户只输入3x3矩阵。我还假设inMatToInv是可逆的。

    /*==========================================================
 * inv_and_mul_3by3.c 
 * inverse 3x3 matrix and multiply it by another 3x3 matrix
 * The calling syntax is: outMatrix = (mat_to_inv,mat_to_mul)
 *========================================================*/

#include "mex.h"

/* The computational routine */
void inv_and_mul_3by3(double *mat_to_inv, double *mat_to_mul, double *out)
{
    // Description : out = inv(mat_to_inv)*mat_to_mul
    double *inversed;
    double det;

    /* Calculate the matrix deteminant */
    det = mat_to_inv[0]*(mat_to_inv[4]*mat_to_inv[8]-mat_to_inv[7]*mat_to_inv[5]) - mat_to_inv[3]*(mat_to_inv[1]*mat_to_inv[8]-mat_to_inv[7]*mat_to_inv[2])+mat_to_inv[6]*(mat_to_inv[1]*mat_to_inv[5]-mat_to_inv[4]*mat_to_inv[2]);

    // Calcualte the inversed matrix
    inversed[0] = (mat_to_inv[4]*mat_to_inv[8] - mat_to_inv[7]*mat_to_inv[5])/det;
    inversed[3] = (mat_to_inv[6]*mat_to_inv[5] - mat_to_inv[3]*mat_to_inv[8])/det;
    inversed[6] = (mat_to_inv[3]*mat_to_inv[7] - mat_to_inv[6]*mat_to_inv[4])/det;
    inversed[1] = (mat_to_inv[7]*mat_to_inv[2] - mat_to_inv[1]*mat_to_inv[8])/det;
    inversed[4] = (mat_to_inv[0]*mat_to_inv[8] - mat_to_inv[6]*mat_to_inv[2])/det;
    inversed[7] = (mat_to_inv[6]*mat_to_inv[1] - mat_to_inv[0]*mat_to_inv[7])/det;
    inversed[2] = (mat_to_inv[1]*mat_to_inv[5] - mat_to_inv[4]*mat_to_inv[2])/det;
    inversed[5] = (mat_to_inv[3]*mat_to_inv[2] - mat_to_inv[0]*mat_to_inv[5])/det;
    inversed[8] = (mat_to_inv[0]*mat_to_inv[4] - mat_to_inv[3]*mat_to_inv[1])/det;

    out[0] = inversed[0]*mat_to_mul[0] + inversed[3]*mat_to_mul[1] + inversed[6]*mat_to_mul[2];
    out[1] = inversed[1]*mat_to_mul[0] + inversed[4]*mat_to_mul[1] + inversed[7]*mat_to_mul[2];
    out[2] = inversed[2]*mat_to_mul[0] + inversed[5]*mat_to_mul[1] + inversed[8]*mat_to_mul[2];
    out[3] = inversed[0]*mat_to_mul[3] + inversed[3]*mat_to_mul[4] + inversed[6]*mat_to_mul[5];
    out[4] = inversed[1]*mat_to_mul[3] + inversed[4]*mat_to_mul[4] + inversed[7]*mat_to_mul[5];
    out[5] = inversed[2]*mat_to_mul[3] + inversed[5]*mat_to_mul[4] + inversed[8]*mat_to_mul[5];
    out[6] = inversed[0]*mat_to_mul[6] + inversed[3]*mat_to_mul[7] + inversed[6]*mat_to_mul[8];
    out[7] = inversed[1]*mat_to_mul[6] + inversed[4]*mat_to_mul[7] + inversed[7]*mat_to_mul[8];
    out[8] = inversed[2]*mat_to_mul[6] + inversed[5]*mat_to_mul[7] + inversed[8]*mat_to_mul[8];
}

/* The gateway function */
void mexFunction( int nlhs, mxArray *plhs[],
                  int nrhs, const mxArray *prhs[])
{
    double *inMatToInv;             /* 3x3 input matrix that is inversed */
    double *inMatToMul;             /* 3x3 input matrix that multiply the inversed matrix*/ 
    double *outMatrix;              /* 3x3 output matrix */

    /* create pointers to the real data in the input matrix  */
    inMatToInv = mxGetPr(prhs[0]);
    inMatToMul = mxGetPr(prhs[1]);

    /* create the output matrix */
    plhs[0] = mxCreateDoubleMatrix(3,3,mxREAL);

    /* get a pointer to the real data in the output matrix */
    outMatrix = mxGetPr(plhs[0]);

    /* call the computational routine */
    inv_and_mul_3by3(inMatToInv,inMatToMul,outMatrix);
}

任何帮助将不胜感激。谢谢，塔米尔

Answer 1

您声明了一个指针double *inversed，但是您没有为它分配任何内存。因此，当您访问inversed[0]时，您会收到错误消息。尝试：

double inversed[9];

Answer 2

I'd recommend using the blas and lapack interface for matrix operations in a C mex file. Have a look at Mathworks documentation on doing this here.

You would be interested in the lapack routines <bean id="oauth2ClientCredentialsTokenEndpointFilter" class="org.springframework.security.oauth2.provider.client.ClientCredentialsTokenEndpointFilter"> <constructor-arg index="0" value="/oauth/authorize" /> <property name="authenticationManager" ref="oauthAuthenticationManager" /> </bean> <bean id="oauthAuthenticationManager" class="org.springframework.security.authentication.ProviderManager"> <constructor-arg> <list> <ref bean="oauthDaoAuthenticationProvider"/> </list> </constructor-arg> </bean> <bean id="oauthDaoAuthenticationProvider" class="org.springframework.security.authentication.dao.DaoAuthenticationProvider"> <property name="userDetailsService" ref="oauthUserDetailService" /> <property name="passwordEncoder" ref="oauthPasswordEncoder" /> </bean> and dgetrf for the matrix inversion and dgetri for matrix multiplication. The lapack interface can be really messy and difficult to grasp but there are lots of references online about them. For example, this stack overflow Q/A.

matlab MEX文件上的运行时错误

2 个答案: