#ifndef LINT
static char SCCSid[] = "@(#)gmapz.c 14.1 12/08/98 Copyright (c) 1991-1996 Varian Assoc.,Inc. All Rights Reserved";
#endif
/* 
 * Varian Assoc.,Inc. All Rights Reserved.
 * This software contains proprietary and confidential
 * information of Varian Assoc., Inc. and its contributors.
 * Use, disclosure and reproduction is prohibited without
 * prior consent.
 */
/*
	- Gradient Shimming -
	array d3 to allow phase evolution of shim gradients
	if p1=0, refocus echo with +/- gradients
	if p1>0, refocus echo with 90-180

 	References:
	P. C. M. van Zijl et al., J. Magn. Reson. A, 111, 203-207 (1994).
	S. Sukumar et al., J. Magn. Reson. A, 125, 159-162 (1997).
	H. Barjat et al., J. Magn. Reson. A, 125, 197-201 (1997).

	Homospoil Gradients: gradtype='nnh'
	See man('gmapsys') for usage.
*/

#include <standard.h>

pulsesequence()
{
   double d3, gzlvl=0.0;
   d3 = getval("d3");
   gzlvl = getval("gzlvl");
   if (gradtype[2]=='h')
      if (p1==0)
         p1 = 2 * pw;

/* --- equilibrium period --- */
   status(A);
      delay(d1);

/* --- set gradients --- */
   status(B);
   pulse(pw, oph);
/* could use shapedpulse("bir4_90_512",pw,oph,rof1,rof2) if available */
   delay(1e-4+d3);

   if (p1 > 0) {
      rgradient('z',gzlvl); 
      delay(at/2+d2); 
      rgradient('z',0.0);
      delay(d2/2);
      pulse(p1, oph); 
      delay(d2/2);
      }
   else
      {
      rgradient('z',-gzlvl);
      delay(at/2+d2); 
      rgradient('z',0.0);
      delay(d2);
      }

/* --- acq. of echo during gradient --- */
   rgradient('z',gzlvl);
   delay(d2);
/* gradient switches off at end of acq. */

}