ref: 653a411b44f1b69d1e7bb7a4433fe48fdb548c45
dir: /lpc10/irc2pc.c/
/*
* 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"
extern int irc2pc_(real *rc, real *pc, integer *order, real *gprime, real *g2pass);
/* ***************************************************************** */
/* IRC2PC Version 48 */
/*
* 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 */
/* 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 * 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_ */