Description of the program: extrema

This program determines the maxima (minima) of one component of a possibly multivariate time series. This corresponds to a Poincaré section at the zeros of the derivative. To get a better estimate of the extremum, a quadratic interpolation is done.

Note: Very sensitive to noise!

Usage:

extrema [Options]

Everything not being a valid option will be interpreted as a potential datafile name. Given no datafile at all, means read stdin. Also - means stdin

Possible options are:

Option Description Default

-l# number of points to use whole file

-x# number of lines to be ignored 0

-m# # of components 1

-c# columns to be read 1,...,# of components

-w# which components to maxi(mini)mize 1

-z determine minima instead of maxima maxima

-t# minimal time required between two extrema 0.0

-o# output file name without file name: 'datafile'.ext
(or stdin.ext if data were read from stdin)
if no -o is given stdout is used

-V# verbosity level
0: only panic messages
1: add input/output messages 1

-h show these options none

Option	Description	Default
-l#	number of points to use	whole file
-x#	number of lines to be ignored	0
-m#	# of components	1
-c#	columns to be read	1,...,# of components
-w#	which components to maxi(mini)mize	1
-z	determine minima instead of maxima	maxima
-t#	minimal time required between two extrema	0.0
-o#	output file name	without file name: 'datafile'.ext (or stdin.ext if data were read from stdin) if no -o is given stdout is used
-V#	verbosity level 0: only panic messages 1: add input/output messages	1
-h	show these options	none

Description of the Output:

The output consists of m+1 columns:

First m columns: The position of the extrema
Last column: The time between the last two extrema

Note that the time given for the first extremum (the first row in the output file) is the absolute time from the start of the time series (t=0) to the first extremum.

View the C-sources.

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