cfetool check - Check a new value against the averages currently in the database

cfetool check name --value|-V value [--path|-p directory name] [--time|-t seconds] [--daily|-d] [--weekly|-w] [--yearly|-y] [--histograms|-H] [--verbose|-v] [--help|-h]

Takes a new value and checks it against the averages currently in the database specified by name, located at the path specified by the -p argument, or the current working directory if the -p argument is ommitted. The value will be associated with the current time, unless the -t option is given. The output indicates how much higher or lower the new value is compared to the averages in the database, in terms of the number of standard deviations.

The -d, -w and -y options specify the databases to check the new value against. If all three options are omitted, only the weekly database will be accessed.

--value|-v value

Specifies the new value to check against the database averages.

--path|-p directory name

The directory in which the database specified by name can be found.

--time|-t

The time the value was collected, in seconds since epoch (January 1st, 1970). If this argument is omitted, the current time will be used.

--daily|-d

Check the new value against the daily averages database.

--weekly|-w

Check the new value against the weekly averages database.

--yearly|-y

Check the new value against the yearly averages database.

--histograms|-H

Check which histogram bucket the new value would fall into. The histogram is divided into 64 buckets, which represent distances from the mean value. Bucket 64 represents two standard deviations above the expected value, and bucket 0 represents two standard deviations below the expected value.

--verbose|-v

Print details of the command's execution to the standard output stream.

--help|-h

Print a short help message and then exit.

Before exiting, CWcfetool check will print one line to the standard output stream, in the following format:

yrly=ynum,bkt=ybkt;wkly=wnum,bkt=wbkt;dly=dnum,bkt=dbkt

ybkt, wbkt and dbkt represent the histogram bucket the given value falls into, and will be 0 for databases that are not being checked against, and if there is no histogram file or the -H option was not specified.

ynum, wnum and dnum will be either the number 0 if the corresponding database was not updated, or a code indicating the state of the given statistic, as compared to an average of equivalent earlier times, as specified below:

 code    high|low|normal   meaning
 -------------------------------------------------------------
  -2     -                 no sigma variation
 -------------------------------------------------------------
  -4     low               within noise threshold, and within
  -5     normal              2 standard deviations from
  -6     high                expected value
 -------------------------------------------------------------
 -14     low               microanomaly: within noise
 -15     normal              threshold, but 2 or more standard
 -16     high                deviations from expected value
 -------------------------------------------------------------
 -24     low               normal; within 1 standard deviation
 -25     normal              from the expected value
 -26     high                
 -------------------------------------------------------------
 -34     low               dev1; more than 1 standard 
 -35     normal              deviation from the expected
 -36     high                value
 ------------------------------------------------------------
 -44     low               dev2; more than 2 standard
 -45     normal              deviations from the expected
 -46     high                value
 -------------------------------------------------------------
 -54     low               anomaly; more than 3 standard
 -55     normal              deviations from the expected
 -56     high                value

Where low indicates that the current value is below both the expected value for the current time position, and the global average value. high indicates that the current value is above those values. normal indicates that the current value is within the range of expected values.

CWcfetool check also exits with a code corresponding to the above table. If more than one database is being checked against, the most negative result from all checks is returned, and the individual results must be obtained from the standard output stream, as described above.

  % cfetool check temperature --path /my/path --value 20 --histograms
  yrly=0,bkt=0;wkly=-6,bkt=51;dly=0,bkt=0

Checks the value 20 against the weekly temperature database and histogram files located in /my/path/ using the current time. The output indicates that the new value given was within cfetool's noise threshold, and also within 2 standard deviations of the previous average stored in the weekly database.

The code and documentation were contributed by Stanford Linear Accelerator Center, a department of Stanford University. This documentation was written by

Elizabeth Cassell <e_a_c@mailsnare.net> and

Alf Wachsmann <alfw@slac.stanford.edu>

 Copyright 2004 Alf Wachsmann <alfw@slac.stanford.edu> and
                Elizabeth Cassell <e_a_c@mailsnare.net>
 All rights reserved.