invert.c

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/*

$Log$
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
 *

*/

/* -- translated by f2c (version 19951025).
 You must link the resulting object file with the libraries:
 -lf2c -lm (in that order)
*/

#include "f2c.h"

#ifdef P_R_O_T_O_T_Y_P_E_S
extern int invert_(integer *order, real *phi, real *psi, real *rc);
#endif

/* **************************************************************** */

/* INVERT Version 45G */

/* $Log$
 * 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 1996/03/18 20:52:47 jaf */
/* Just added a few comments about which array indices of the arguments */
/* are used, and mentioning that this subroutine has no local state. */

/* Revision 1.2 1996/03/13 16:51:32 jaf */
/* Comments added explaining that none of the local variables of this */
/* subroutine need to be saved from one invocation to the next. */

/* Eliminated a comment from the original, describing a local array X */
/* that appeared nowhere in the code. */

/* Revision 1.1 1996/02/07 14:47:20 jaf */
/* Initial revision */


/* **************************************************************** */

/* Invert a covariance matrix using Choleski decomposition method. */

/* Input: */
/* ORDER - Analysis order */
/* PHI(ORDER,ORDER) - Covariance matrix */
/* Indices (I,J) read, where ORDER .GE. I .GE. J .GE. 1.*/
/* All other indices untouched. */
/* PSI(ORDER) - Column vector to be predicted */
/* Indices 1 through ORDER read. */
/* Output: */
/* RC(ORDER) - Pseudo reflection coefficients */
/* Indices 1 through ORDER written, and then possibly read.
*/
/* Internal: */
/* V(ORDER,ORDER) - Temporary matrix */
/* Same indices written as read from PHI. */
/* Many indices may be read and written again after */
/* initially being copied from PHI, but all indices */
/* are written before being read. */

/* NOTE: Temporary matrix V is not needed and may be replaced */
/* by PHI if the original PHI values do not need to be preserved. */

/* Subroutine */ int invert_(integer *order, real *phi, real *psi, real *rc)
{
 /* 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_ */