NAME

cru_composer - specification for composing consecutive edges in a graph

SYNOPSIS

#include <cru/cru.h>

typedef struct cru_composer_s
{
   int co_fix;
   int destructive;
   struct cru_cqop_s labeler;
   struct cru_prop_pair_s co_props;
} *cru_composer;

DESCRIPTION

This structure parameterizes the cru_composed library function with necessary information initialized by the application to create new edges in a graph determined by end-to-end pairs of existing edges. The fields have these interpretations.

• The structure in the co_props field is used to compute two arbitrarily user-defined properties associated with each vertex in a given graph, one designated as its local and the other as its adjacent property, according to usual conventions for cru_prop_pair structures.
• For every outgoing edge from every vertex to an adjacent vertex, and for every outgoing edge from the adjacent vertex, the quarternary predicate in the labeler.qpred field is passed the local property of the vertex as its first operand, the label on the incident edge to the adjacent vertex as its second operand, the adjacent property of the adjacent vertex as its next operand, and the label on the outgoing edge from the adjacent vertex its last operand.
• If the predicate referenced by the labeler.qpred field returns a non-zero value, then the same operands in the same order are passed to the quarternary operator referenced by the labeler.qop field, which is expected to return the label of a new edge to be included in the graph. The new edge is made to connect the vertex whose local property is given as the first parameter directly to the terminus of the edge whose label is given as the last parameter.
• If the destructive field is non-zero, then the incident edge to the adjacent vertex is deleted from the graph. The outgoing edge from it is retained regardless.
• If the co_fix field is non-zero, then this procedure is iterated in multiple passes over the graph until the predicate calls for the creation of no further edges.

The labeler.qpred field may be omitted or initialized as NULL, in which case the labeler.qop function is invoked unconditionally. If the composition pertains to a graph whose edge labels are scalar values, then the labeler.qop field also may be omitted or initialized as NULL. In that case, the created edge is labeled identically to the incident edge.

FILES

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

SEE ALSO

cru, cru_bop, cru_bpred, cru_builder, cru_built, cru_cbop, cru_classifier, cru_class_of, cru_class_size, cru_composed, 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