NAME

cru_classifier - equivalence class specification for the cru library

SYNOPSIS

#include <cru/cru.h>

typedef struct cru_classifier_s
{
   struct cru_prop_s cl_prop;
   struct cru_order_s cl_order;
} *cru_classifier;

DESCRIPTION

This structure parameterizes the cru_partition_of library function with necessary information initialized by the application to compute a partition on the vertices in a graph, and is also a field in the cru_merger structure used to parameterize the cru_merged library function.

For every vertex in a given graph, a property specified by the cl_prop field is computed by the usual cru_prop calling conventions. Any two vertices whose properties are equal according to the cl_order field with usual cru_order calling conventions are deemed to be members of the same equivalence class.

Some default values can be inferred automatically.

• When the cru_classifier is used as a top level structure to parameterize the cru_partition_of function, the vertex reduction in the cl_prop.vertex.reduction field is not used and may be omitted or initialized as NULL.
• If the whole cl_prop field is omitted or zero-filled, then the property associated with each vertex is identical to the vertex.
• If the vertex fold in the cl_prop.vertex has an omitted or NULL map destructor cl_prop.vertex.m_free and the cl_order field is omitted or zero-filled, then a default scalar ordering is inferred for purposes of comparison.

As these defaults imply, a zero-filled classifier describes the partition of every vertex in a class by itself.

ERRORS

The predicate in the cl_order field must be algebraically reflexive, transitive, and symmetric. Not meeting this requirement is an error. There is no way for cru to enforce this requirement automatically, but anomalous results are likely to follow from not meeting it.

FILES

/usr/local/include/cru/data_types.h

SEE ALSO

cru, cru_bop, cru_bpred, cru_builder, cru_built, cru_cbop, cru_class_of, cru_class_size, cru_composed, cru_composer, cru_connect, cru_connector, cru_cqop, cru_crossed, cru_crosser, cru_ctop, cru_ctop_pair, cru_ctop_quad, cru_data_types, cru_deduplicated, cru_destructor, cru_destructor_pair, cru_edge_count, cru_fabricated, cru_fabricator, cru_filter, cru_filtered, cru_fold, cru_free_kill_switch, cru_free_later, cru_free_now, cru_free_partition, cru_function_types, cru_get, cru_hash, cru_induced, cru_inducer, cru_kernel, cru_kill, cru_killed, cru_mapreduced, cru_mapreducer, cru_merged, cru_merger, cru_mutated, cru_mutator, cru_new_kill_switch, cru_nop, cru_order, cru_order_pair, cru_partition_of, cru_plan, cru_postponed, cru_postponer, cru_prop, cru_prop_pair, cru_pruner, cru_qop, cru_qpred, cru_set, cru_sig, cru_singleton, cru_split, cru_splitter, cru_spread, cru_strerror, cru_stretch, cru_stretched, cru_stretcher, cru_subconnector, cru_terminus_count, cru_top, cru_tpred, cru_united, cru_uop, cru_vertex_count, cru_zone

AUTHOR

Dennis Furey (milonga@delayinsensitive.com)

PROJECT PAGE

https://github.com/gueststar/cru