R调用的C代码不断崩溃
下面是我写的C代码的一部分。 函数foo将在R中调用。代码不断导致R崩溃，我将问题缩小到这个outer()函数，该函数用于计算外部和或差。 请注意注释掉的部分：如果我没有注释掉， 如果每个数组包含超过1000个数据点 ，该函数将导致R崩溃。 如果我将其评论出来，我可以计算出明显更长的数组的外部和/差异而没有问题（例如，每个数组超过100000个数据点）。 我想知道问题是什么……谢谢！
#include #include #include #include #include void outer(double *x1, double *x2, int *n, int operation, double *output){ int i, j; if(operation==1){ for(i=0; i<*n; i++){ for(j=0; j<*n; j++){ output[(*n)*i+j]=x1[j]+x2[i]; } } } else if(operation==2){ for(i=0; i<*n; i++){ for(j=0; j<*n; j++){ output[(*n)*i+j]=x1[j]-x2[i]; //Rprintf("%d ", (*n)*i+j); //<-----------HERE } } } } void foo(double *x, double *y, int *npred, int *nsamp){ int oper=2; double xouter[*nsamp], youter[*nsamp]; double outer_temp_x[(*nsamp)*(*nsamp)], outer_temp_y[(*nsamp)*(*nsamp)]; outer(x, x, nsamp, oper, &outer_temp_x[0]); outer(y, y, nsamp, oper, &outer_temp_y[0]); }
//编译代码后，我使用R中的代码来调用函数：
dyn.load("foo.so") x=as.matrix(rnorm(10000)) y=rlnorm(10000) invisible(.C("foo", x=as.double(as.vector(x)), y=as.double(y), npred=as.integer(ncol(x)), nsamp=as.integer(length(y)) )
我认为它正在超越堆栈并造成麻烦。
试试这个：
void foo(double *x, double *y, int *npred, int *nsamp){ int oper=2; double xouter[*nsamp], youter[*nsamp]; // The prior code allocated on the stack. Here, we make a pair of calls // to 'malloc' to allocate memory for the arrays. This gets memory from // the heap. The stack is fairly limited, but the heap is huge. // 'malloc' returns a pointer to the allocated memory. double* outer_temp_x=malloc(sizeof(double)*(*nsamp)*(*nsamp)); double* outer_temp_y=malloc(sizeof(double)*(*nsamp)*(*nsamp)); outer(x, x, nsamp, oper, &outer_temp_x[0]); outer(y, y, nsamp, oper, &outer_temp_y[0]); // The downside of allocating on the heap, is that you must release the // memory at some point. Otherwise you have what's called a "memory leak." // 'free' is the function to free the memory, and it is called on the // pointer value returned by 'malloc'. free(outer_temp_x); free(outer_temp_y); }