/* rank_vertices.c

   This is a program to test the rank_vertices() function (a part of
   nelder-mead).

   It generates all vectors of length n with entries coming from
   the set {0,1,2,...,n-1}.

   Then it lets n vary from 3 to N, where N is #defined below.

   For each generated vector, it runs the given rank_vertices() function.

   If the result of rank_vertices() is incorrect, it prints a diagnostic,
   otherwise no putput is generated.

   Rouben Rostamian
   November 2003
*/

#include <stdio.h>

#define N 5

/* ---- Replace the following BROKEN function with a good one ---- */
static void rank_vertices(double *v, 
                size_t n, size_t *ia, size_t *iy, size_t *iz)
{
        size_t i;
        
        *ia = *iy = *iz = 0;

        for (i=1; i < n; i++){
                if (v[i] >= v[*iz]){
                        *iy = *iz;
                        *iz = i;
                }
                if (v[i] < v[*ia])
                        *ia = i;
                else if (v[i] >= v[*iy])
                        *iy = i;
        }
}

void print_row(double *a, size_t n)
{
	size_t i;

	for (i=0; i<n; i++)
		printf("%g ", a[i]);
}

int incr(double *a, size_t n, size_t k)
{
	if (k==n)
		return 1;

	if (a[k] < n-1) {
		a[k]++;
		return 0;
	} else {
		a[k] = 0;
		return incr(a, n, k+1);
	}
}

/* Receives a vector a[] of length n containing entries from the set 0..(n-1).
   It "increments" the vector, as if the vector entries were the digits of
   an number in base n.  Returns 0 on success or 1 on failure, which happens
   when all vector entires have hit their max.
*/
int increment(double *a, size_t n)
{
	return incr(a, n, 0);
}

void test_result(double *a, size_t n, size_t ia, size_t iy, size_t iz)
{
	if (ia == iy || iy == iz || iz == ia) {
		printf("vector: ");
		print_row(a, n);
		printf(" => ");
		printf("ia = %u, iy = %u, iz = %u\n", ia, iy, iz);
		return;
	}

	if (!(a[ia] <= a[iy] && a[iy] <= a[iz])) {
		printf("vector: ");
		print_row(a, n);
		printf("ia = %u, iy = %u, iz = %u\n", ia, iy, iz);
		printf("a[%u] <= a[%u] && a[%u] <= a[%u] failed!\n",
				ia, iy, iy, iz);
		return;
	}
}

int main(void)
{
	double a[N+1];
	size_t ia, iy, iz;
	size_t i, n;

	for (n=3; n<=N; n++) {
		for (i=0; i<n; i++)
			a[i] = 0;
		do {
			rank_vertices(a, n, &ia, &iy, &iz);
			test_result(a, n, ia, iy, iz);
		} while (increment(a,n)!=1);
	}

	return 0;
}