/* maxheap version */
static void fvec_k_min_maxheap (const float *val, int n,
int *idx, int k)
{
fbinheap_t *mh = fbinheap_new (k);
int i;
for (i = 0; i < n; i++)
fbinheap_add (mh, i, val[i]); /* -val because we want maxes instead of mins */
fbinheap_sort_labels (mh, idx);
fbinheap_delete (mh);
}
void mexFunction (int nlhs, mxArray *plhs[],
int nrhs, const mxArray*prhs[])
{
if (nrhs != 4)
mexErrMsgTxt ("Invalid number of input arguments: either 2 for initialization or 4 for feeding the heap");
if (nlhs != 2)
mexErrMsgTxt ("2 output arguments are expected");
if (mxGetClassID(ARGIN_VAL) != mxSINGLE_CLASS || mxGetClassID(ARGIN_VALH) != mxSINGLE_CLASS)
mexErrMsgTxt ("need single precision array for values");
if (mxGetClassID(ARGIN_IDS) != mxUINT32_CLASS || mxGetClassID(ARGIN_IDSH) != mxUINT32_CLASS)
mexErrMsgTxt ("need uint32 arrays for indices");
/* Variables defining the heap */
int k = mxGetM (ARGIN_VALH); /* Number of neighbors for the heap */
int nh = mxGetN (ARGIN_VALH); /* Number of heaps */
if (mxGetM(ARGIN_IDSH) != k || mxGetN (ARGIN_IDSH) != nh)
mexErrMsgTxt ("Inconsistent sizes for the heap parameters");
/* Values to be considered for being added in the heap */
int n = mxGetM (ARGIN_VAL);
int nh2 = mxGetN (ARGIN_VAL);
if (mxGetM(ARGIN_IDS) != n || mxGetN (ARGIN_IDS) != 1 || nh2 != nh)
mexErrMsgTxt ("Invalid sizes for the values/indexes to be added");
/* Pointer to the data to manipulate */
float * val = (float*) mxGetPr (ARGIN_VAL);
int * ids = (int*) mxGetPr (ARGIN_IDS);
/* Produce output heap and populate it */
ARGOUT_VAL = mxCreateNumericMatrix (k, nh, mxSINGLE_CLASS, mxREAL);
ARGOUT_IDS = mxCreateNumericMatrix (k, nh, mxUINT32_CLASS, mxREAL);
float * bh_val = (float*) mxGetPr (ARGOUT_VAL);
int * bh_ids = (int*) mxGetPr (ARGOUT_IDS);
memcpy (bh_val, mxGetPr (ARGIN_VALH), k * nh * sizeof (*bh_val));
memcpy (bh_ids, mxGetPr (ARGIN_IDSH), k * nh * sizeof (*bh_ids));
int i, j;
for (j = 0 ; j < nh ; j++)
fbinheap_add (k, bh_val + j * k, bh_ids + j * k, n, val + j * n, ids);
}
int merge_ordered_sets (const int **labels,const float **vals,
const int *sizes,int k,
int **labels_out,float **vals_out) {
int i,j;
int n_out = ivec_sum (sizes, k);
int *all_labels = ivec_new (n_out);
float *all_vals = fvec_new (n_out);
/* Maxheap:
* * maxheap label = index of table in 0..k-1
* * maxheap val = - (label from labels table)
*
* If maxheap val does not fit in a float (if label>2**24), it
* triggers an assertion. Time to implement a maxheap with int
* values...
*/
fbinheap_t *mh = fbinheap_new(k);
/* current index on table k */
int indices[k];
for ( i = 0 ; i < k ; i++) {
if (sizes[i] == 0)
continue;
indices[i] = 0;
int label = labels[i][0];
float mh_val = -label;
assert ((int)(-mh_val) == label || !"lost precision in int->float conversion");
fbinheap_add (mh, i, mh_val);
}
int all_i = 0;
while (mh->k>0) {
/* smallest available label */
i = mh->label[1]; /* index of table */
j = (int)(-mh->val[1]); /* label */
/* I don't dare compiling with -DNDEBUG */
/* assert(j==labels[i][indices[i]]); */
all_labels[all_i] = j;
all_vals[all_i] = vals[i][indices[i]];
all_i++;
/* remove handled label */
fbinheap_pop (mh);
indices[i]++;
if (indices[i] < sizes[i]) { /* push next label from this table */
int label = labels[i][indices[i]];
float mh_val = -label;
assert ((int)(-mh_val) == label || !"lost precision in int->float conversion");
fbinheap_add (mh, i, mh_val);
}
}
fbinheap_delete (mh);
assert (all_i == n_out);
*labels_out = all_labels;
*vals_out = all_vals;
return n_out;
}
