cru_induced - compute a graph metric inductively
#include <cru/cru.h>
void *cru_induced
(
cru_graph
g
,
cru_inducer
i
,
cru_kill_switch
k
,
unsigned
lanes
,
int *err
)
This function computes a metric about a graph g without modifying it according to user-defined criteria set by i following the usual cru_inducer calling conventions, which associate a result with each vertex allowed to depend on the results associated with its adjacent vertices. Alternatively, a NULL value of i is allowed and causes a NULL value to be returned.
The value passed through k may be either a cru_kill_switch previously obtained by the cru_new_kill_switch function or a NULL pointer denoted alternatively by UNKILLABLE. If code running in another thread passes the kill switch to cru_kill while the operation is in progress, then the operation is interrupted. In this case, a NULL value is returned.
The lanes parameter specifies the number of worker threads to be used for the operation. Higher numbers up to the number of CPU cores on the host are conducive to higher performance.
For purposes of memory management, no parameters are consumed.
On successful completion, the returned value the result computed for the graph g according to the cru_inducer specification i. In the event of any error, a NULL pointer is returned.
The err parameter is used to report any events preventing successful completion of the requested operation to the caller. If *err is zero on entry and the operation does not succeed, then *err is assigned a non-zero number. If the operation does not succeed because a user-defined callback function reports an error, then the number reported by the callback function is assigned to *err. Positive numbers are for POSIX or user-defined error codes, negative numbers down to -CRU_MAX_ERR are specific to cru, and other negative numbers are allowed as user-defined error codes.
Values of *err listed below refer to errors that are detected and handled. Unlisted values in the range of -CRU_INT_ERR through -CRU_MAX_ERR likely indicate internal errors attributable to bugs in cru. Any other unlisted values may indicate memory corruption, invalid usage of the API, or conditions relevant to user-defined callback functions.
ENOMEM
There is insufficient memory to allocate all necessary resources.
EAGAIN
Resources or permissions are insufficient to create a thread.
CRU_BADGPH
The parameter g refers to an invalid or corrupted graph.
CRU_BADKIL
The parameter k refers to an invalid or corrupted kill switch structure.
CRU_INTKIL
The operation was stopped by user intervention using the kill switch k.
CRU_INCINV
The field i->in_zone.offset is non-zero but the vertex i->in_zone.initial_vertex is not in the graph g.
CRU_UNDMAP
The i->in_fold.map field is NULL.
CRU_UNDRED
The i->in_fold.reduction field is NULL and not inferrable.
CRU_UNDVAC
The i->in_fold.vacuous_case field is NULL.
A nullary operator is always required via the i->in_fold.vacuous_case field because deadlock avoidance presupposes a vertex in the graph having no prerequisites.
/usr/local/include/cru/cru.h
/usr/local/include/cru/data_types.h
/usr/local/include/cru/error_codes.h
cru, cru_bop, cru_bpred, cru_builder, cru_built, cru_cbop, cru_classifier, 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_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
Dennis Furey (milonga@delayinsensitive.com)
https://github.com/gueststar/cru