- Documentation
- Reference manual
- The SWI-Prolog library
- library(aggregate): Aggregation operators on backtrackable predicates
- library(ansi_term): Print decorated text to ANSI consoles
- library(apply): Apply predicates on a list
- library(assoc): Association lists
- library(broadcast): Broadcast and receive event notifications
- library(charsio): I/O on Lists of Character Codes
- library(check): Consistency checking
- library(clpb): CLP(B): Constraint Logic Programming over Boolean Variables
- library(clpfd): CLP(FD): Constraint Logic Programming over Finite Domains
- library(clpqr): Constraint Logic Programming over Rationals and Reals
- library(csv): Process CSV (Comma-Separated Values) data
- library(dcg/basics): Various general DCG utilities
- library(dcg/high_order): High order grammar operations
- library(debug): Print debug messages and test assertions
- library(dicts): Dict utilities
- library(error): Error generating support
- library(fastrw): Fast reading and writing of terms
- library(gensym): Generate unique symbols
- library(heaps): heaps/priority queues
- library(increval): Incremental dynamic predicate modification
- library(intercept): Intercept and signal interface
- library(iostream): Utilities to deal with streams
- library(listing): List programs and pretty print clauses
- library(lists): List Manipulation
- library(macros): Macro expansion
- library(main): Provide entry point for scripts
- library(nb_set): Non-backtrackable set
- library(www_browser): Open a URL in the users browser
- library(occurs): Finding and counting sub-terms
- library(option): Option list processing
- library(optparse): command line parsing
- library(ordsets): Ordered set manipulation
- library(pairs): Operations on key-value lists
- library(persistency): Provide persistent dynamic predicates
- library(pio): Pure I/O
- library(portray_text): Portray text
- library(predicate_options): Declare option-processing of predicates
- library(prolog_coverage): Coverage analysis tool
- library(prolog_debug): User level debugging tools
- library(prolog_jiti): Just In Time Indexing (JITI) utilities
- library(prolog_trace): Print access to predicates
- library(prolog_versions): Demand specific (Prolog) versions
- library(prolog_xref): Prolog cross-referencer data collection
- library(quasi_quotations): Define Quasi Quotation syntax
- library(random): Random numbers
- library(rbtrees): Red black trees
- library(readutil): Read utilities
- library(record): Access named fields in a term
- library(registry): Manipulating the Windows registry
- library(rwlocks): Read/write locks
- library(settings): Setting management
- library(statistics): Get information about resource usage
- library(strings): String utilities
- library(simplex): Solve linear programming problems
- library(solution_sequences): Modify solution sequences
- library(tables): XSB interface to tables
- library(terms): Term manipulation
- library(thread): High level thread primitives
- library(thread_pool): Resource bounded thread management
- library(ugraphs): Graph manipulation library
- library(url): Analysing and constructing URL
- library(varnumbers): Utilities for numbered terms
- library(yall): Lambda expressions
- The SWI-Prolog library
- Packages
- Reference manual
A.52 library(statistics): Get information about resource usage
This library provides predicates to obtain information about resource usage by your program. The predicates of this library are for human use at the toplevel: information is printed. All predicates obtain their information using public low-level primitives. These primitives can be use to obtain selective statistics during execution.
- [det]statistics
- Print information about resource usage using print_message/2.
- See also
- All statistics printed are obtained through statistics/2.
- [det]statistics(-Stats:dict)
- Stats is a dict representing the same information as statistics/0. This convience function is primarily intended to pass statistical information to e.g., a web client. Time critical code that wishes to collect statistics typically only need a small subset and should use statistics/2 to obtain exactly the data they need.
- [nondet]thread_statistics(?Thread, -Stats:dict)
- Obtain statistical information about a single thread. Fails silently of
the Thread is no longer alive.
Stats is a dict containing status, time and stack-size information about Thread. - [nondet]time(:Goal)
- Execute Goal, reporting statistics to the user. If Goal
succeeds non-deterministically, retrying reports the statistics for
providing the next answer.
Statistics are retrieved using thread_statistics/3 on the calling thread. Note that not all systems support thread-specific CPU time. Notable, this is lacking on MacOS X.
- See also
- - statistics/2
for obtaining statistics in your program and understanding the reported
values.
- call_time/2, call_time/3 to obtain the timing in a dict. - bug
- Inference statistics are often a few off.
- call_time(:Goal, -Time:dict)
- call_time(:Goal, -Time:dict, -Result)
- Call Goal as call/1,
unifying Time with a dict that provides information on the
resource usage. If Goal succeeds with a choice point,
backtracking reports the time used to find the next answer,
failure or exception. If Goal succeeds deterministically no
choice point is left open. Currently Time contains the keys
below. Future versions may provide additional keys.
- wall:Seconds
- cpu:Seconds
- inferences:Count
call_time/2 is defined as below. Note that for call_time/2 the time is only available if Goal succeeds.
call_time(Goal, Time) :- call_time(Goal, Time, Result), call(Result).Result is one of true,falseorthrow(E), depending on whether or not the goal succeeded or raised an exception. Note that Result may be called using call/1 to propagate the failure or exception.