irc2pc.c

Go to the documentation of this file.

/*
 
$Log$
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  22:31:56  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 irc2pc_(real *rc, real *pc, integer *order, real *gprime, real *g2pass);
#endif
 
/* ***************************************************************** */
 
/*  IRC2PC Version 48 */
 
/* $Log$
 * 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  22:31:56  jaf
 * Initial revision
 * */
/* Revision 1.3  1996/03/20  15:47:19  jaf */
/* Added comments about which indices of array arguments are read or */
/* written. */
 
/* Revision 1.2  1996/03/14  16:59:04  jaf */
/* Comments added explaining that none of the local variables of this */
/* subroutine need to be saved from one invocation to the next. */
 
/* Revision 1.1  1996/02/07 14:47:27  jaf */
/* Initial revision */
 
 
/* ***************************************************************** */
 
/*   Convert Reflection Coefficients to Predictor Coeficients */
 
/* Inputs: */
/*  RC     - Reflection coefficients */
/*           Indices 1 through ORDER read. */
/*  ORDER  - Number of RC's */
/*  GPRIME - Excitation modification gain */
/* Outputs: */
/*  PC     - Predictor coefficients */
/*           Indices 1 through ORDER written. */
/*           Indices 1 through ORDER-1 are read after being written. */
/*  G2PASS - Excitation modification sharpening factor */
 
/* This subroutine has no local state. */
 
/* Subroutine */ int irc2pc_(real *rc, real *pc, integer *order, real *gprime,
     real *g2pass)
{
    /* System generated locals */
    integer i__1, i__2;
 
    /* Builtin functions */
    double sqrt(doublereal);
 
    /* Local variables */
    real temp[10];
    integer i__, j;
 
/*  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  22:31:56  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 */
/*       Local variables that need not be saved */
    /* Parameter adjustments */
    --pc;
    --rc;
 
    /* Function Body */
    *g2pass = 1.f;
    i__1 = *order;
    for (i__ = 1; i__ <= i__1; ++i__) {
    *g2pass *= 1.f - rc[i__] * rc[i__];
    }
    *g2pass = *gprime * (real)sqrt(*g2pass);
    pc[1] = rc[1];
    i__1 = *order;
    for (i__ = 2; i__ <= i__1; ++i__) {
    i__2 = i__ - 1;
    for (j = 1; j <= i__2; ++j) {
        temp[j - 1] = pc[j] - rc[i__] * pc[i__ - j];
    }
    i__2 = i__ - 1;
    for (j = 1; j <= i__2; ++j) {
        pc[j] = temp[j - 1];
    }
    pc[i__] = rc[i__];
    }
    return 0;
} /* irc2pc_ */