VS2010 error C2668: “log”: 对重载函数的调用不明确

Question

#include "miinclude.h"

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
if(nrhs!=1)
mexErrMsgTxt("Usage [jointentropy] = progname(jointprob_table).");
if(nlhs > 1)
mexErrMsgTxt("Too many output argument <jointentropy>.");

//check if parameters are correct

long i,j;

double *pab = mxGetPr(prhs[0]);
long pabhei = mxGetM(prhs[0]);
long pabwid = mxGetN(prhs[0]);

double **pab2d = new double * [pabwid];
for(j=0;j<pabwid;j++)
pab2d[j] = pab + (long)j*pabhei;

//calculate the joint entropy

double muInf = 0;

muInf = 0.0;
for (j=0;j<pabwid;j++) // should for pb
{
for (i=0;i<pabhei;i++) // should for pa
{
if (pab2d[j][i]>0) //!=0
{
muInf -= pab2d[j][i] * log(double(pab2d[j][i]));
}
}
}

muInf /= log(2);

plhs[0] = mxCreateDoubleMatrix(1,1, mxREAL);
*mxGetPr(plhs[0]) = muInf;

//free memory
if(pab2d){delete []pab2d;}

return;
}

运行上面的程序会出错，
estcondentropy.cpp(65) : error C2668: “log”: 对重载函数的调用不明确
d:\visual c++\VC\INCLUDE\math.h(575): 可能是“long double log(long double)”
d:\visual c++\VC\INCLUDE\math.h(527): 或 “float log(float)”
d:\visual c++\VC\INCLUDE\math.h(120): 或 “double log(double)”
尝试匹配参数列表“(int)”时
请问要如何修改？谢谢~

Answer 1

d:\visual c++\VC\INCLUDE\math.h(575): 可能是“long double log(long double)”
d:\visual c++\VC\INCLUDE\math.h(527): 或 “float log(float)”
d:\visual c++\VC\INCLUDE\math.h(120): 或 “double log(double)”
都已经提示要如何修改了
~~~~~~~~~~~~~~~~

Answer 2

muInf /= log(2);
改成
muInf /= log((double)(2.0));
出错原因说的够明白了,就不能动下脑