/* _ctest.c 19.5.2017/SM (19.5.2017)
*/

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <math.h>
#include <survo.h>
#include <survoext.h>

#define MMAX 1001
#define PI 3.141592653589793
unsigned int n,m;
char bin[MMAX];
double  ee[MMAX],rr[MMAX];
int ns[MMAX];
__int64 fs[MMAX];
FILE *temp;

void main(argc,argv)
int argc; char *argv[];
    {
    int i;
    __int64 j;
    double a,accuracy;

    if (argc==1) return;
    s_init(argv[1]);
    if (g<2)
        {
        sur_print("\nCTEST n,accuracy                                    ");
        sur_print("\nscans all 2^[(n-1)/2-1] positive linear combinations");
        sur_print("\nof edge lengths of a n-sided regular polygon        ");
        sur_print("\nwith coefficients +1 or -1                          ");
        sur_print("\nand checks that only one of them is equal to        ");
        sur_print("\ncot((2*i+1)*pi/(2*n)), i=1,2,...,(n-1)/2.           ");
        sur_print("\nfor a prime number n.                               ");
        WAIT; return;
        }
    n=atoi(word[1]);
    m=(n-1)/2;
    accuracy=atof(word[2]);
    for (i=0; i<m; ++i)
       {
       ee[i]=2*sin(((n+1)/2-i-1)*PI/(double)n);
       rr[i]=1.0/tan((2*i+1)*PI/(double)(2*n));
       printf("\nE%d=%g R%d=%g",i+1,ee[i],i+1,rr[i]);
       }

    for (i=0; i<m; ++i) bin[i]='0'; bin[m]=EOS;
    j=(__int64)0;

    while (1)
        {
        a=0.0;
        for (i=0; i<m; ++i)
            if (bin[i]=='0') a-=ee[i]; else a+=ee[i];
        ++j;
        if (a>0.0) // check positive combinations
            for (i=0; i<m; ++i)
                {
                if (fabs(a-rr[i])<accuracy)
                    { ++ns[i]; fs[i]=j; printf("X"); }
                }

        // next linear combination 0 corresponds to coefficient -1
        i=m-1;
        while (bin[i]=='1' && i>=0) --i;
        if (i<0) break;
        bin[i]='1';
        ++i; for (; i<m; ++i) bin[i]='0';
        }

    for (i=0; i<m; ++i)
       if (ns[i]!=1) break;
    if (i<m)
        {
        sur_print("\nNot unique solution for n=%d\n",n);
        for(i=0; i<m; ++i) printf("%d ",ns[i]); getch(); getch(); getch();
        }
    else
        {
        sprintf(sbuf,"CTEST%d.TXT",n);
        temp=fopen(sbuf,"wt");
        fprintf(temp,"%s\n",sbuf);
        for (i=0; i<m; ++i) fprintf(temp,"%I64u\n",fs[i]);
        fprintf(temp,"\n#comb=%I64u",j);
        fclose(temp);
        }
    return;
    }