void pcshft(float a, float b, float d[], int n){	int k,j;	float fac,cnst;	cnst=2.0/(b-a);	fac=cnst;	for (j=1;j<n;j++) {		d[j] *= fac;		fac *= cnst;	}	cnst=0.5*(a+b);	for (j=0;j<=n-2;j++)		for (k=n-2;k>=j;k--)			d[k] -= cnst*d[k+1];}