Programmer Guide/Command Reference/EVAL/corrfun: Difference between revisions
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;Usage: | ;Usage: | ||
:{|class="keinrahmen" | :{|class="keinrahmen" | ||
|<code>corrfun(''x''<sub>vector</sub> {, ''n'' {, ''scale''}})</code> | |<code>corrfun(''x''<sub>vector</sub> {, ''n'' {, ''scale'' {, cyclic}}})</code> | ||
| ... autocorrelation of ''x'' | | ... autocorrelation of ''x'' | ||
|- | |- | ||
|<code>corrfun(''x''<sub>vector</sub>, ''y''<sub>vector</sub> {, ''n'' {, ''scale''}})</code> | |<code>corrfun(''x''<sub>vector</sub>, ''y''<sub>vector</sub> {, ''n'' {, ''scale'' {, cylic}}})</code> | ||
| ... cross correlation of ''x'' and ''y'' | | ... cross correlation of ''x'' and ''y'' | ||
|} | |} | ||
| Line 22: | Line 22: | ||
| ... "unbiased", each lag ''i'' is scaled by the number of correlated elements (<code>1/(ncol(''x'')-''i'')</code>) | | ... "unbiased", each lag ''i'' is scaled by the number of correlated elements (<code>1/(ncol(''x'')-''i'')</code>) | ||
|} | |} | ||
::{|class="keinrahmen" | |||
|''cyclic=0'' | |||
| ... normal correlation (default) | |||
|- | |||
|''cyclic!=0'' | |||
| ... cyclic correlation (<code>a[i]*b[(i+lag)%ncol(a)]<code>) | |||
|} | |||
;Result: The autocorrelation of the data vector ''x'' or the cross correlation function of the vectors ''x'' and ''y''. The result is a scalar (if ''n''=1) or a vector with ''n'' elements. | ;Result: The autocorrelation of the data vector ''x'' or the cross correlation function of the vectors ''x'' and ''y''. The result is a scalar (if ''n''=1) or a vector with ''n'' elements. | ||
;See also: [[../corr|corr]] | ;See also: [[../corr|corr]] | ||
[[../#Functions|<function list>]] | [[../#Functions|<function list>]] | ||
Revision as of 09:30, 1 September 2023
Compute the autocorrelation or cross-correlation function.
- Usage
corrfun(xvector {, n {, scale {, cyclic}}})... autocorrelation of x corrfun(xvector, yvector {, n {, scale {, cylic}}})... cross correlation of x and y
- x, y
- data vectors
- n
- the number of lags; 0 < n <
ncol(x)(default=ncol(x)/2) - scale
- specifies the scaling of the function:
scale=0 ... no scaling (default) scale=1 ... "biased", each lag i is scaled by the length of x ( 1/ncol(x))scale=2 ... "unbiased", each lag i is scaled by the number of correlated elements ( 1/(ncol(x)-i))
cyclic=0 ... normal correlation (default) cyclic!=0 ... cyclic correlation ( a[i]*b[(i+lag)%ncol(a)])
- Result
- The autocorrelation of the data vector x or the cross correlation function of the vectors x and y. The result is a scalar (if n=1) or a vector with n elements.
- See also
- corr
