Programmer Guide/Command Reference/EVAL/dct: Difference between revisions
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Revision as of 17:31, 18 November 2010
dct
Discrete Cosine Transform.
Usage:
dct(x {, n {, 0}})
Function:
Computes the discrete cosine transform of x. n must be in the range 1..nrow(x). The default is n = nrow(x).
Result:
A vector containing the first n dct coefficients.
Usage:
dct(x, n, 1)
Function:
Computes the inverse dct of x.
If n <= nrow(x):
Only the first n coefficients of x are used, the others are set to 0. Output length = nrow(x).
If n > nrow(x):
x is expanded with zeros to n elements.
Result:
A vector containing the inverse dct.
