SUPEF - Wiener predictive error filtering

supef <stdin >stdout [optional parameters]

Required parameters:
dt is mandatory if not set in header

Optional parameters:
minlag=dt first lag of prediction filter (sec)
maxlag=last lag default is (tmax-tmin)/20
pnoise=0.001 relative additive noise level
mincorr=tmin start of autocorrelation window (sec)
maxcorr=tmax end of autocorrelation window (sec)
showwiener=0 =1 to show Wiener filter on each trace
mix=1,... array of weights (floats) for moving
average of the autocorrelations

Trace header fields accessed: ns, dt
Trace header fields modified: none

To get the Wiener filters into an ascii file:
... | supef ... showwiener=1 2>file | ... (sh or ksh)
(... | supef ... showwiener=1 | ...) >&file (csh)


Credits:
CWP: Shuki Ronen, Jack K. Cohen, Ken Larner
CWP: John Stockwell, added mixing feature (April 1998)

A. Ziolkowski, "Deconvolution", for value of maxlag default:
page 91: imaxlag < nt/10. I took nt/20.

Notes:
The prediction error filter is 1,0,0...,0,-wiener[0], ...,
so no point in explicitly forming it.

If imaxlag < 2*iminlag - 1, then we don't need to compute the
autocorrelation for lags:
imaxlag-iminlag+1, ..., iminlag-1
It doesn't seem worth the duplicated code to implement this.

Trace header fields accessed: ns