dauto [window_size] < input.doubles > output.doublesDAUTO(1)
NAME
dauto - compute the unbiased autocorrelation function of a stream of doubles
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SYNOPSIS
DESCRIPTION
dauto reads a stream of double-precision floating-point numbers from standard input, computes an unbiased estimate of the autocorrelation function over successive fixed-size windows, and writes the resulting double-precision values to standard output.
Input is processed in non-overlapping records of window_size samples (default 512). For each record of L samples, dauto estimates the autocorrelation at lags 0 through L-1, writing L values per record. The estimate at lag 0 is based on all L samples and the estimate at lag L-1 on only one; zeros are assumed outside the record. The estimate is unbiased by scaling each lag by a factor inversely proportional to the number of contributing samples. A final partial record shorter than window_size is zero-padded.
Both standard input and standard output must be redirected; dauto exits with a usage message if either is a terminal. See dauto2(1) for a biased variant.
OPTIONS
- window_size
-
Number of samples per record, controlling the maximum lag computed. Must be a positive integer. Defaults to 512 if omitted.
EXAMPLES
Example 1. Autocorrelate a sampled signal
dauto 1024 < signal.doubles > autocor.doublesComputes the unbiased autocorrelation of a stream of double-precision values in 1024-sample windows. The resulting stream of doubles can be fed to dpeak(1) to locate dominant periodicities in the signal.
SEE ALSO
brlcad(1), dauto2(1), damdf(1), dconv(1), dpeak(1)
AUTHOR
BRL-CAD Team
COPYRIGHT
This software is Copyright (c) 1989-2026 by the United States Government as represented by U.S. Army Research Laboratory.
BUG REPORTS
Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org