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Issue #13478: document timeit.default_timer()
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@ -101,9 +101,19 @@ The module defines the following public class:
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timeit.Timer('for i in xrange(10): oct(i)', 'gc.enable()').timeit()
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Starting with version 2.6, the module also defines two convenience functions:
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The module also defines three convenience functions:
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.. function:: default_timer()
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Define a default timer, in a platform specific manner. On Windows,
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:func:`time.clock` has microsecond granularity but :func:`time.time`'s
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granularity is 1/60th of a second; on Unix, :func:`time.clock` has 1/100th of
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a second granularity and :func:`time.time` is much more precise. On either
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platform, :func:`default_timer` measures wall clock time, not the CPU
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time. This means that other processes running on the same computer may
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interfere with the timing.
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.. function:: repeat(stmt[, setup[, timer[, repeat=3 [, number=1000000]]]])
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Create a :class:`Timer` instance with the given statement, setup code and timer
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@ -168,13 +178,9 @@ similarly.
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If :option:`-n` is not given, a suitable number of loops is calculated by trying
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successive powers of 10 until the total time is at least 0.2 seconds.
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The default timer function is platform dependent. On Windows,
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:func:`time.clock` has microsecond granularity but :func:`time.time`'s
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granularity is 1/60th of a second; on Unix, :func:`time.clock` has 1/100th of a
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second granularity and :func:`time.time` is much more precise. On either
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platform, the default timer functions measure wall clock time, not the CPU time.
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This means that other processes running on the same computer may interfere with
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the timing. The best thing to do when accurate timing is necessary is to repeat
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:func:`default_timer` measurations can be affected by other programs running on
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the same machine, so
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the best thing to do when accurate timing is necessary is to repeat
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the timing a few times and use the best time. The :option:`-r` option is good
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for this; the default of 3 repetitions is probably enough in most cases. On
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Unix, you can use :func:`time.clock` to measure CPU time.
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