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Defines | |
| #define | BETA_MAX DBL_MAX |
| #define | PLOGP(x) ((x)*log((x))) |
Functions | |
| void | vl_aib_calculate_information (VlAIB *aib, double *I, double *H) |
| void | vl_aib_delete (VlAIB *aib) |
| Deletes AIB data structure. | |
| void | vl_aib_merge_nodes (VlAIB *aib, vl_uint i, vl_uint j, vl_uint new) |
| void | vl_aib_min_beta (VlAIB *aib, vl_uint *besti, vl_uint *bestj, double *minbeta) |
| VlAIB * | vl_aib_new (double *Pcx, vl_uint nvalues, vl_uint nlabels) |
| Allocates and initializes the internal data structure. | |
| vl_uint * | vl_aib_new_nodelist (vl_uint nentries) |
| double * | vl_aib_new_Pc (double *Pcx, vl_uint nvalues, vl_uint nlabels) |
| double * | vl_aib_new_Px (double *Pcx, vl_uint nvalues, vl_uint nlabels) |
| void | vl_aib_normalize_P (double *P, vl_uint nelem) |
| VL_EXPORT void | vl_aib_process (VlAIB *aib) |
| Runs AIB on Pcx. | |
| void | vl_aib_update_beta (VlAIB *aib) |
Define Documentation
| #define PLOGP | ( | x | ) | ((x)*log((x))) |
Function Documentation
| void vl_aib_calculate_information | ( | VlAIB * | aib, |
| double * | I, | ||
| double * | H | ||
| ) |
| void vl_aib_delete | ( | VlAIB * | aib | ) |
| void vl_aib_min_beta | ( | VlAIB * | aib, |
| vl_uint * | besti, | ||
| vl_uint * | bestj, | ||
| double * | minbeta | ||
| ) |
| VlAIB* vl_aib_new | ( | double * | Pcx, |
| vl_uint | nvalues, | ||
| vl_uint | nlabels | ||
| ) |
Allocates and initializes the internal data structure.
------------------------------------------------------------------
- Parameters:
-
Pcx A pointer to a 2D array of probabilities nvalues The number of rows in the array nlabels The number of columns in the array
Creates a new VlAIB struct containing pointers to all the data that will be used during the AIB process.
Allocates memory for the following:
- Px (nvalues*sizeof(double))
- Pc (nlabels*sizeof(double))
- nodelist (nvalues*sizeof(vl_uint))
- which (nvalues*sizeof(vl_uint))
- beta (nvalues*sizeof(double))
- bidx (nvalues*sizeof(vl_uint))
- parents ((2*nvalues-1)*sizeof(vl_uint))
- costs (nvalues*sizeof(double))
Since it simply copies to pointer to Pcx, the total additional memory requirement is:
(3*nvalues+nlabels)*sizeof(double) + 4*nvalues*sizeof(vl_uint)
- Returns:
- An allocated and initialized VlAIB pointer
| vl_uint* vl_aib_new_nodelist | ( | vl_uint | nentries | ) |
| double* vl_aib_new_Pc | ( | double * | Pcx, |
| vl_uint | nvalues, | ||
| vl_uint | nlabels | ||
| ) |
| double* vl_aib_new_Px | ( | double * | Pcx, |
| vl_uint | nvalues, | ||
| vl_uint | nlabels | ||
| ) |
| void vl_aib_normalize_P | ( | double * | P, |
| vl_uint | nelem | ||
| ) |
| VL_EXPORT void vl_aib_process | ( | VlAIB * | aib | ) |
Runs AIB on Pcx.
------------------------------------------------------------------
- Parameters:
-
aib AIB object to process
The function runs Agglomerative Information Bottleneck (AIB) on the joint probability table aib->Pcx which has labels along the columns and feature values along the rows. AIB iteratively merges the two values of the feature x that causes the smallest decrease in mutual information between the random variables x and c.
Merge operations are arranged in a binary tree. The nodes of the tree correspond to the original feature values and any other value obtained as a result of a merge operation. The nodes are indexed in breadth-first order, starting from the leaves. The first index is zero. In this way, the leaves correspond directly to the original feature values. In total there are 2*nvalues-1 nodes.
The results may be accessed through vl_aib_get_parents which returns an array with one element per tree node. Each element is the index the parent node. The root parent is equal to zero. The array has 2*nvalues-1 elements.
Feature values with null probability are ignored by the algorithm and their nodes have parents indexing a non-existent tree node (a value bigger than 2*nvalues-1).
Then the function will also compute the information level after each merge. vl_get_costs will return a vector with the information level after each merge. cost has nvalues entries: The first is the value of the cost functional before any merge, and the others are the cost after the nvalues-1 merges.
| void vl_aib_update_beta | ( | VlAIB * | aib | ) |