void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray
*prhs[])
{
int i, j;
int N, Nperm;
int *d;
int subs[2];
double *ptr;
gsl_permutation *c;
if(nrhs != 1)
mexErrMsgTxt("1 input required");
if(nlhs != 1)
mexErrMsgTxt("Requires one output.");
if(mxGetM(prhs[0]) * mxGetN(prhs[0]) != 1)
mexErrMsgTxt("N must be scalar");
N = mxGetScalar(prhs[0]);
Nperm = (int) (gsl_sf_fact(N));
c = gsl_permutation_calloc (N);
gsl_permutation_init(c);
plhs[0] = mxCreateDoubleMatrix(Nperm, N, mxREAL);
ptr = mxGetPr(plhs[0]);
for(i = 0; i < Nperm; i++)
{
d = gsl_permutation_data(c);
for(j = 0; j < N; j++)
{
subs[0] = i;
subs[1] = j;
ptr[mxCalcSingleSubscript(plhs[0], 2, subs)] =
(double)d[j] + 1.;
}
gsl_permutation_next(c);
}
gsl_permutation_free(c);
}
int
main (void)
{
gsl_permutation * p = gsl_permutation_alloc (3) ;
gsl_permutation_init (p) ;
do
{
gsl_permutation_fprintf (stdout, p, " %u") ;
printf("\n") ;
}
while (gsl_permutation_next(p) == GSL_SUCCESS);
}
static VALUE rb_gsl_permutation_next(VALUE obj)
{
gsl_permutation *p = NULL;
Data_Get_Struct(obj, gsl_permutation, p);
return INT2FIX(gsl_permutation_next(p));
}
int rgb_permutations(Test **test,int irun)
{
uint i,j,k,permindex=0,t;
Vtest vtest;
double *testv;
size_t ps[4096];
gsl_permutation** lookup;
MYDEBUG(D_RGB_PERMUTATIONS){
printf("#==================================================================\n");
printf("# rgb_permutations: Debug with %u\n",D_RGB_PERMUTATIONS);
}
/*
* Number of permutations. Note that the minimum ntuple value for a
* valid test is 2. If ntuple is less than 2, we choose the default
* test size as 5 (like operm5).
*/
if(ntuple<2){
test[0]->ntuple = 5;
} else {
test[0]->ntuple = ntuple;
}
k = test[0]->ntuple;
nperms = gsl_sf_fact(k);
/*
* A vector to accumulate rands in some sort order
*/
testv = (double *)malloc(k*sizeof(double));
MYDEBUG(D_RGB_PERMUTATIONS){
printf("# rgb_permutations: There are %u permutations of length k = %u\n",nperms,k);
}
/*
* Create a test, initialize it.
*/
Vtest_create(&vtest,nperms);
vtest.cutoff = 5.0;
for(i=0;i<nperms;i++){
vtest.x[i] = 0.0;
vtest.y[i] = (double) test[0]->tsamples/nperms;
}
MYDEBUG(D_RGB_PERMUTATIONS){
printf("# rgb_permutations: Allocating permutation lookup table.\n");
}
lookup = (gsl_permutation**) malloc(nperms*sizeof(gsl_permutation*));
for(i=0;i<nperms;i++){
lookup[i] = gsl_permutation_alloc(k);
}
for(i=0;i<nperms;i++){
if(i == 0){
gsl_permutation_init(lookup[i]);
} else {
gsl_permutation_memcpy(lookup[i],lookup[i-1]);
gsl_permutation_next(lookup[i]);
}
}
MYDEBUG(D_RGB_PERMUTATIONS){
for(i=0;i<nperms;i++){
printf("# rgb_permutations: %u => ",i);
gsl_permutation_fprintf(stdout,lookup[i]," %u");
printf("\n");
}
}
/*
* We count the order permutations in a long string of samples of
* rgb_permutation_k non-overlapping rands. This is done by:
* a) Filling testv[] with rgb_permutation_k rands.
* b) Using gsl_sort_index to generate the permutation index.
* c) Incrementing a counter for that index (a-c done tsamples times)
* d) Doing a straight chisq on the counter vector with nperms-1 DOF
*
* This test should be done with tsamples > 30*nperms, easily met for
* reasonable rgb_permutation_k
*/
for(t=0;t<test[0]->tsamples;t++){
/*
* To sort into a perm, test vector needs to be double.
*/
for(i=0;i<k;i++) {
testv[i] = (double) gsl_rng_get(rng);
MYDEBUG(D_RGB_PERMUTATIONS){
printf("# rgb_permutations: testv[%u] = %u\n",i,(uint) testv[i]);
}
}
gsl_sort_index(ps,testv,1,k);
MYDEBUG(D_RGB_PERMUTATIONS){
for(i=0;i<k;i++) {
printf("# rgb_permutations: ps[%u] = %lu\n",i,ps[i]);
}
}
for(i=0;i<nperms;i++){
if(memcmp(ps,lookup[i]->data,k*sizeof(size_t))==0){
permindex = i;
MYDEBUG(D_RGB_PERMUTATIONS){
printf("# Found permutation: ");
gsl_permutation_fprintf(stdout,lookup[i]," %u");
printf(" = %u\n",i);
}
break;
}
}
vtest.x[permindex]++;
MYDEBUG(D_RGB_PERMUTATIONS){
printf("# rgb_permutations: Augmenting vtest.x[%u] = %f\n",permindex,vtest.x[permindex]);
}
}
