www.pudn.com > lpc.zip > invert_i.c

/*****************************************************************
*
*	INVERT Version 45G
*
*****************************************************************
*
*  Invert a covariance matrix using Choleski decomposition method
*
*  Inputs:
*    ORDER            - Analysis ORDER
*    PHI(ORDER,ORDER) - Covariance matrix
*    PSI(ORDER)       - Column vector to be predicted
*  Outputs:
*    RC(ORDER)        - Pseudo reflection coefficients
*  Internal:
*    V(ORDER,ORDER)   - Temporary matrix
*    X(ORDER)         - Column scaling factors
*
*  NOTE: Temporary matrix V is not needed and may be replaced
*    by PHI if the original PHI values do not need to be preserved.
*/

#include "config.ch"
#include "lpcdefs.h"
#include "ourstuff.h"


invert_i(phi, psi, rc)
int_type phi[MAXORD][MAXORD], psi[];
int_type rc[MAXORD][AF];
{
int_type i, j, k;
static int_type save;

/*  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).		*/


for(j=0;j>11)*save>>8);*/
		  /*printf("i:%d j:%d   %d * %d= %x\n",i,j, phi[i][k], save, phi[i][k]*save);*/
		  /* printf("temp:%d %d   phi:%d\n",temp, temp<<11, phi[i][j]);*/
		  phi[i][j] -= (((long_type)phi[i][k]*(long_type)save)>>8);
		}
	}
	
/*  Compute intermediate results, which are similar to RC's	*/

	if((int_type)phi[j][j] == 0 ) break;
	rc[j][AF-1] = psi[j];
	for(k=0;k>14);
		/*printf("result: %d\n", rc[j][AF-1]<<14);*/
	}
	/*printf("\n");*/
	/*printf("int j:%d rc:%d  phi:%d ",j, rc[j][AF-1]<<14,phi[j][j]<<14);*/
	rc[j][AF-1] = (rc[j][AF-1]<<14)/phi[j][j];
	/*printf("result: %f\n", rc[j][AF-1]/4096.0);*/
	rc[j][AF-1] = mmax(mmin(rc[j][AF-1],16367),-16367);
			   /*printf("rc: %f\n", rc[j][AF-1]/4096.0);*/
	
	
}
if(phi[j][j] == 0 )	{

/*  Zero out higher order RC's if algorithm terminated early	*/

	for(i=j;i