c** Performs mirror-image linear prediction on the workspace
c** to double the size of the FID in the workspace
c** FELIX macro, Biosym
c** Author: Roger A. Chylla
c** Reference:  Zhu, G. and Bax, A. (1990) J. Magn. Reson. 90, 405-410
c**
def pts 0;			Begin initialization...	
def dpts 0;	
def lpp 0;	
def npts 0;		
def poles 0;
def peaks 0;
def lpts 0;			End initialization
c**
eva pts (&datsiz);		Store data size
eva dpts (&pts*2);		Get double # complex data pts
eva lpp (&pts-1);		Get # complex pts for back prediction
eva npts (&dpts-1);		Get # complex pts for lp after back prediction
eva lpts (&dpts+&lpp);		Get final # complex pts after lp
eva poles (&dpts/4);		Get # poles for lp
eva peaks (&dpts/4);		Get # peaks for lp
c**
c**	The following section uses the workspace and the 1st buffer to
c**	reflect the current FID 'backwards' in time.  This is done by
c**	taking the complex conjugate of the workspace and reversing
c**	the direction of the FID.
c**	Begin backward reflection...
c**
zf &dpts;			Zero fill to double the size of workspace 
psh;				Push workspace onto bufer
shr &lpp;			Shift right # complex pts for back prediction
xsh;				Exchange contents of workspace and 1st buffer
eva datsiz (&pts);		Set size of workspace to original data size
cnj;				Get complex conjugate of workspace
rev;				Reverse dir. of workspace so lpt is now fpt
eva datsiz (&lpp);		Set size of workspace to lpp 
zf &dpts;			Zero fill to double the size of workspace
adb 1;				Add contents of workspace to 1st buffer
pop;				Make 1st buffer the workspace
eva datsiz (&npts);		Set data size of new FID size
c**
c**	End backward reflection...
c**
lpl &npts &poles &peaks &dpts &lpts;	Perform linear prediction
shl &lpp;				Discard negative time points
eva datsiz (&dpts);			Set data size to new FID size
c**
ret;	Return to calling function