SLEPTAP is the jSpectral module of jLab.

 SLEPTAP  Calculate Slepian tapers.
    [PSI,LAMBDA]=SLEPTAP(M,P,K) calculates the K lowest-order Slepian
    tapers PSI of length M and time-bandwidth product P, together with
    their eigenvalues LAMBDA. PSI is M x K and LAMBDA is K x 1.
    K is optional and defaults to 2P-1.  
    P is optional and defaults to 4.
    For M<=512, SLEPTAP uses the tridiagonal method described in Percival 
    and Walden (1993).  For M>512, it first computes tapers for M=512 and 
    then spline-interpolates.  (Tests show spline interpolation is far
    superior to linear interpolation for this problem.)   
    The tapers are normalized to have unit energy.
    Computing multiple taper lengths simultaneously
    M may also be an array of lengths.  In this case PSI is a cell array of 
    matrices, with PSI{1} being M(1) x K, PSI{2} being M(2) x K, etc., 
    while LAMBDA is again K x 1.
    By default, SLEPTAP will down-interpolate the M=512 tapers to all 
    shorter lengths, an approximation that is very good for data lengths
    greater than say M=64, and resulting in a vast computational savings. 
    Because short data segments are difficult to extract reliable spectral
    information from anyway, this should be sufficient for most purposes.
    Alternatively, SLEPTAP(...,'exact') will directly compute solutions of 
    PSI and LAMBDA for entries m for which M(m)<=512.  In this case, LAMBDA
    will be a K x M matrix.  This algorithm, like the default behavior, 
    will spline-interpolate PSI from the M=512 solution to larger M values.
    SLEPTAP(...,'exact','parallel') will parallelize this computation using
    a PARFOR loop.  This requires Matlab's Parallel Computing Toolbox.
    'sleptap --t' runs some tests.  
    Usage:  [psi,lambda]=sleptap(n); 
    This is part of JLAB --- type 'help jlab' for more information
    (C) 2000--2021 J.M. Lilly --- type 'help jlab_license' for details

contents | allhelp | index