Fsdb::F...ngstats(3)

📦
version 3.9 · 3 versions
, in epel 9

💖 NAME 💖

okay bestie, welcome to the Fsdb::F...ngstats(3) page from the User Contributed Perl Documentation — this one is dbcolmovingstats: compute moving statistics over a window of a column of data. ✨

🌸 SYNOPSIS 🌸

dbcolmovingstats [-am] [-w WINDOW] [-e EmptyValue] [-k KEY] column

🦋 DESCRIPTION 🦋

So we’re computing moving statistics over a COLUMN of data. Records with non-numeric data are considered null and do not contribute to the stats — unless you use -a, in which case they get treated as zeros instead.

Statistics are computed over a WINDOW of samples of data. 👑

🚧 In-progress note from 2020-11-12, but not completed: alternatively, if a key column is given with -k KEY, then we treat the key column as a time value and compute the time-weighted mean.

Currently we compute mean and sample standard deviation. (Note: we only compute sample standard deviation, not full population.) Optionally, with -m we also compute median. (Currently there is no support for generalized quantiles.)

Values before a sufficient number have been accumulated are given the empty value if you specified one with -e. If no empty value is given, stats are computed on as many as possible.

Dbcolmovingstats runs in O(1) memory, but must buffer a full window of data. Quantiles currently will repeatedly sort the window and so may perform poorly with wide windows. 😭

✨ OPTIONS ✨

  • -a or --include-non-numeric — Compute stats over all records (treat non-numeric records as zero rather than just ignoring them).
  • -w or --window WINDOW — WINDOW of how many items to accumulate (defaults to 10). (For compatibility with fsdb-1.x, -n is also supported.)
  • -k or --key KEY — The KEY specifies a field that is used to evaluate the window---a window must span at most this range of value so the key field. (For example, if KEY is the time and window is 60, then enough samples will be added to make at most 60s of observations. With a key, sampling can be irregular.) If key is specified, we also output a moving_n field for how many samples are in each window.
  • -m or --median — Show median of the window in addition to mean.
  • -e E or --empty E — Give value E as the value for empty (null) records. This null value is then output before a full window is accumulated.
  • -f FORMAT or --format FORMAT — Specify a printf(3)-style format for output mean and standard deviation. Defaults to "%.5g".

Eventually we expect to support other options of dbcolstats.

This module also supports the standard fsdb options:

  • -d — Enable debugging output.
  • -i or --input InputSource — Read from InputSource, typically a file name, or "-" for standard input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
  • -o or --output OutputDestination — Write to OutputDestination, typically a file name, or "-" for standard output, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
  • --autorun or --noautorun — By default, programs process automatically, but Fsdb::Filter objects in Perl do not run until you invoke the run() method. The "--(no)autorun" option controls that behavior within Perl.
  • --help — Show help.
  • --man — Show full manual.

🎀 SAMPLE USAGE 🎀

🍓 Input:

#fsdb date  epoch count
19980201        886320000       6
19980202        886406400       8
19980203        886492800       19
19980204        886579200       53
19980205        886665600       20
19980206        886752000       18
19980207        886838400       5
19980208        886924800       9
19980209        887011200       22
19980210        887097600       22
19980211        887184000       36
19980212        887270400       26
19980213        887356800       23
19980214        887443200       6

🧚 Command:

cat data.fsdb | dbmovingstats -e - -w 4 count

🌈 Output:

#fsdb date epoch count moving_mean moving_stddev
19980201        886320000       6       -       -
19980202        886406400       8       -       -
19980203        886492800       19      -       -
19980204        886579200       53      21.5    21.764
19980205        886665600       20      25      19.442
19980206        886752000       18      27.5    17.02
19980207        886838400       5       24      20.445
19980208        886924800       9       13      7.1647
19980209        887011200       22      13.5    7.8528
19980210        887097600       22      14.5    8.8129
19980211        887184000       36      22.25   11.026
19980212        887270400       26      26.5    6.6081
19980213        887356800       23      26.75   6.3966
19980214        887443200       6       22.75   12.473
#   | dbcolmovingstats -e - -n 4 count

👑 SEE ALSO 👑

  • Fsdb.
  • dbcolstats.
  • dbmultistats.
  • dbrowdiff.

💀 BUGS 💀

Currently there is no support for generalized quantiles.

💅 CLASS FUNCTIONS 💅

💖 new

$filter = new Fsdb::Filter::dbcolmovingstats(@arguments);

Create a new dbcolmovingstats object, taking command-line arguments.

💖 set_defaults

$filter->set_defaults();

Internal: set up defaults.

💖 parse_options

$filter->parse_options(@ARGV);

Internal: parse command-line arguments.

💖 setup

$filter->setup();

Internal: setup, parse headers.

💖 run

$filter->run();

Internal: run over each rows.

Copyright (C) 1991-2022 by John Heidemann <johnh@isi.edu>

This program is distributed under terms of the GNU general public license, version 2. See the file COPYING with the distribution for details.

okay bestie, that’s the whole page — signed off for Fsdb::F...ngstats(3) with perl v5.32.1, dated 2024-08-02. Periodt. 🎀💜

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