corr.c

#include <math.h>
#include <stdio.h>
#include <stdlib.h>

double t[16][256];
double tdev[16][256];
double u[16][256];
double udev[16][256];
void readdata(void)
{
    int lines;
    int b;
    int size;
    int j;
    long long packets;
    double cycles;
    double deviation;
    double aboveaverage;
    double avdev;
    for (lines = 0;lines < 8192;++lines) {
        if (scanf("%d%d%d%lld%lf%lf%lf%lf"
        ,&b
        ,&size
        ,&j
        ,&packets
        ,&cycles
        ,&deviation
        ,&aboveaverage
        ,&avdev
        ) != 8) exit(100);

        b &= 15;
        j &= 255;
        if (lines < 4096) {
            t[b][j] = aboveaverage;
            tdev[b][j] = avdev;
        } else {
            u[b][j] = aboveaverage;
            udev[b][j] = avdev;
        }
    }
}

double c[256];
double v[256];
int cpos[256];
int cposcmp(const void *v1,const void *v2)
{
    int *i1 = (int *) v1;
    int *i2 = (int *) v2;
    if (c[255 & *i1] < c[255 & *i2]) return 1;
    if (c[255 & *i1] > c[255 & *i2]) return -1;
    return 0;
}

void processdata(void)
{
    int b;
    int i;
    int j;
    int numok;
    double z;
    FILE *fp = fopen("/data/local/tmp/correlation.txt", "w+");
    for (b = 0;b < 16;++b) {
        for (i = 0;i < 256;++i) {
            c[i] = v[i] = 0;
            cpos[i] = i;
            for (j = 0;j < 256;++j) {
                c[i] += t[b][j] * u[b][i ^ j]; //correlation
                z = tdev[b][j] * u[b][i ^ j];
                v[i] += z * z;
                z = t[b][j] * udev[b][i ^ j];
                v[i] += z * z;
            }
        }

        qsort(cpos,256,sizeof(int),cposcmp);
        numok = 0;
        for (i = 0;i < 256;++i)
            if (c[cpos[0]] - c[cpos[i]] < 10 * sqrt(v[cpos[i]]))
                ++numok;

        printf("%3d %2d ",numok,b);
        for (i = 0;i < 256;++i)
            if (c[cpos[0]] - c[cpos[i]] < 10 * sqrt(v[cpos[i]]))
                printf(" %02x",cpos[i]);
        printf("\n");
    }
}

int main()
{
    readdata();
    processdata();
    return 0;
}