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# counter(n) 2.0.4 tcllib "Counters and Histograms"

## Name

counter - Procedures for counters and histograms

## Synopsis

- package require Tcl 8
- package require counter ?2.0.4?

- ::counter::init tag args
- ::counter::count tag ?delta? ?instance?
- ::counter::start tag instance
- ::counter::stop tag instance
- ::counter::get tag args
- ::counter::exists tag
- ::counter::names
- ::counter::histHtmlDisplay tag args
- ::counter::reset tag args

## Description

The counter package provides a counter facility and can compute statistics and histograms over the collected data.

::counter::init tag args

  This defines a counter with the name tag. The args determines the characteristics of the counter. The args are

  -group name

    Keep a grouped counter where the name of the histogram bucket is passed into ::counter::count.

  -hist bucketsize

    Accumulate the counter into histogram buckets of size bucketsize. For example, if the samples are millisecond time values and bucketsize is 10, then each histogram bucket represents time values of 0 to 10 msec, 10 to 20 msec, 20 to 30 msec, and so on.

  -hist2x bucketsize

    Accumulate the statistic into histogram buckets. The size of the first bucket is bucketsize, each other bucket holds values 2 times the size of the previous bucket. For example, if bucketsize is 10, then each histogram bucket represents time values of 0 to 10 msec, 10 to 20 msec, 20 to 40 msec, 40 to 80 msec, and so on.

  -hist10x bucketsize

    Accumulate the statistic into histogram buckets. The size of the first bucket is bucketsize, each other bucket holds values 10 times the size of the previous bucket. For example, if bucketsize is 10, then each histogram bucket represents time values of 0 to 10 msec, 10 to 100 msec, 100 to 1000 msec, and so on.

  -lastn N

    Save the last N values of the counter to maintain a "running average" over the last N values.

  -timehist secsPerMinute

    Keep a time-based histogram. The counter is summed into a histogram bucket based on the current time. There are 60 per-minute buckets that have a size determined by secsPerMinute, which is normally 60, but for testing purposes can be less. Every "hour" (i.e., 60 "minutes") the contents of the per-minute buckets are summed into the next hourly bucket. Every 24 "hours" the contents of the per-hour buckets are summed into the next daily bucket. The counter package keeps all time-based histograms in sync, so the first secsPerMinute value seen by the package is used for all subsequent time-based histograms.

::counter::count tag ?delta? ?instance?

  Increment the counter identified by tag. The default increment is 1, although you can increment by any value, integer or real, by specifying delta. You must declare each counter with ::counter::init to define the characteristics of counter before you start to use it. If the counter type is -group, then the counter identified by instance is incremented.

::counter::start tag instance

  Record the starting time of an interval. The tag is the name of the counter defined as a -hist value-based histogram. The instance is used to distinguish this interval from any other intervals that might be overlapping this one.

::counter::stop tag instance

  Record the ending time of an interval. The delta time since the corresponding ::counter::start call for instance is recorded in the histogram identified by tag.

::counter::get tag args

  Return statistics about a counter identified by tag. The args determine what value to return:

  -total

    Return the total value of the counter. This is the default if args is not specified.

  -totalVar

    Return the name of the total variable. Useful for specifying with -textvariable in a Tk widget.

  -N

    Return the number of samples accumulated into the counter.

  -avg

    Return the average of samples accumulated into the counter.

  -avgn

    Return the average over the last N samples taken. The N value is set in the ::counter::init call.

  -hist bucket

    If bucket is specified, then the value in that bucket of the histogram is returned. Otherwise the complete histogram is returned in array get format sorted by bucket.

  -histVar

    Return the name of the histogram array variable.

  -histHour

    Return the complete hourly histogram in array get format sorted by bucket.

  -histHourVar

    Return the name of the hourly histogram array variable.

  -histDay

    Return the complete daily histogram in array get format sorted by bucket.

  -histDayVar

    Return the name of the daily histogram array variable.

  -resetDate

    Return the clock seconds value recorded when the counter was last reset.

  -all

    Return an array get of the array used to store the counter. This includes the total, the number of samples (N), and any type-specific information. This does not include the histogram array.

::counter::exists tag

  Returns 1 if the counter is defined.

::counter::names

  Returns a list of all counters defined.

::counter::histHtmlDisplay tag args

  Generate HTML to display a histogram for a counter. The args control the format of the display. They are:

  -title string

    Label to display above bar chart

  -unit unit

    Specify minutes, hours, or days for the time-base histograms. For value-based histograms, the unit is used in the title.

  -images url

    URL of /images directory.

  -gif filename

    Image for normal histogram bars. The filename is relative to the -images directory.

  -ongif filename

    Image for the active histogram bar. The filename is relative to the -images directory.

  -max N

    Maximum number of value-based buckets to display.

  -height N

    Pixel height of the highest bar.

  -width N

    Pixel width of each bar.

  -skip N

    Buckets to skip when labeling value-based histograms.

  -format string

    Format used to display labels of buckets.

  -text boolean

    If 1, a text version of the histogram is dumped, otherwise a graphical one is generated.

::counter::reset tag args

  Resets the counter with the name tag to an initial state. The args determine the new characteristics of the counter. They have the same meaning as described for ::counter::init.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category counter of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## Keywords

counting, histogram, statistics, tallying

## Category

Data structures