invert.c File Reference

#include "f2c.h"

Include dependency graph for invert.c:

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Functions
int	invert_ (integer *order, real *phi, real *psi, real *rc)

Function Documentation

invert_()

int invert_	(	integer *	order,
		real *	phi,
		real *	psi,
		real *	rc
	)

Definition at line 93 of file invert.c.

References abs, max, min, and order.

Referenced by analys_().

{
    /* System generated locals */
    unsigned i__2;
    integer phi_dim1, phi_offset, i__1, i__3;
    real r__1, r__2;

    /* Local variables */
    real save;
    integer i__, j, k;
    real v[100]   /* was [10][10] */;

/*       Arguments */
/* $Log$
 * Revision 1.15  2004/06/26 03:50:14  markster
 * Merge source cleanups (bug #1911)
 *
 * Revision 1.14  2003/02/12 13:59:15  matteo
 * mer feb 12 14:56:57 CET 2003
 *
 * Revision 1.1.1.1  2003/02/12 13:59:15  matteo
 * mer feb 12 14:56:57 CET 2003
 *
 * Revision 1.2  2000/01/05 08:20:39  markster
 * Some OSS fixes and a few lpc changes to make it actually work
 *
 * Revision 1.1  1996/08/19  22:32:00  jaf
 * Initial revision
 * */
/* Revision 1.3  1996/03/29  22:03:47  jaf */
/* Removed definitions for any constants that were no longer used. */

/* Revision 1.2  1996/03/26  19:34:33  jaf */
/* Added comments indicating which constants are not needed in an */
/* application that uses the LPC-10 coder. */

/* Revision 1.1  1996/02/07  14:43:51  jaf */
/* Initial revision */

/*   LPC Configuration parameters: */
/* Frame size, Prediction order, Pitch period */
/*    Parameters/constants */
/*       Local variables that need not be saved */
/*  Decompose PHI into V * D * V' where V is a triangular matrix whose */
/*   main diagonal elements are all 1, V' is the transpose of V, and */
/*   D is a vector.  Here D(n) is stored in location V(n,n). */
    /* Parameter adjustments */
    --rc;
    --psi;
    phi_dim1 = *order;
    phi_offset = phi_dim1 + 1;
    phi -= phi_offset;

    /* Function Body */
    i__1 = *order;
    for (j = 1; j <= i__1; ++j) {
   i__2 = *order;
   for (i__ = j; i__ <= i__2; ++i__) {
       v[i__ + j * 10 - 11] = phi[i__ + j * phi_dim1];
   }
   i__2 = j - 1;
   for (k = 1; k <= i__2; ++k) {
       save = v[j + k * 10 - 11] * v[k + k * 10 - 11];
       i__3 = *order;
       for (i__ = j; i__ <= i__3; ++i__) {
      v[i__ + j * 10 - 11] -= v[i__ + k * 10 - 11] * save;
       }
   }
/*  Compute intermediate results, which are similar to RC's */
   if ((r__1 = v[j + j * 10 - 11], abs(r__1)) < 1e-10f) {
       goto L100;
   }
   rc[j] = psi[j];
   i__2 = j - 1;
   for (k = 1; k <= i__2; ++k) {
       rc[j] -= rc[k] * v[j + k * 10 - 11];
   }
   v[j + j * 10 - 11] = 1.f / v[j + j * 10 - 11];
   rc[j] *= v[j + j * 10 - 11];
/* Computing MAX */
/* Computing MIN */
   r__2 = rc[j];
   r__1 = min(r__2,.999f);
   rc[j] = max(r__1,-.999f);
    }
    return 0;
/*  Zero out higher order RC's if algorithm terminated early */
L100:
    i__1 = *order;
    for (i__ = j; i__ <= i__1; ++i__) {
   rc[i__] = 0.f;
    }
/*  Back substitute for PC's (if needed) */
/* 110   DO J = ORDER,1,-1 */
/*       PC(J) = RC(J) */
/*       DO I = 1,J-1 */
/*          PC(J) = PC(J) - PC(I)*V(J,I) */
/*       END DO */
/*    END DO */
    return 0;
} /* invert_ */