小编Ing*_*ngo的帖子

我想优化这个简单的循环:

unsigned int i;
while(j-- != 0){ //j is an unsigned int with a start value of about N = 36.000.000
   float sub = 0;
   i=1;
   unsigned int c = j+s[1];
   while(c < N) {
       sub += d[i][j]*x[c];//d[][] and x[] are arrays of float
       i++;
       c = j+s[i];// s[] is an array of unsigned int with 6 entries.
   }
   x[j] -= sub;                        // only one memory-write per j
}

使用4000 MHz AMD Bulldozer,该循环的执行时间约为1秒.我想过SIMD和OpenMP(我通常用它来获得更快的速度),但这个循环是递归的.

有什么建议？