add numerical recipes library

lib/nr/ansi/recipes/mglin.c

@@ -0,0 +1,80 @@
+
+#define NRANSI
+#include "nrutil.h"
+#define NPRE 1
+#define NPOST 1
+#define NGMAX 15
+
+void mglin(double **u, int n, int ncycle)
+{
+	void addint(double **uf, double **uc, double **res, int nf);
+	void copy(double **aout, double **ain, int n);
+	void fill0(double **u, int n);
+	void interp(double **uf, double **uc, int nf);
+	void relax(double **u, double **rhs, int n);
+	void resid(double **res, double **u, double **rhs, int n);
+	void rstrct(double **uc, double **uf, int nc);
+	void slvsml(double **u, double **rhs);
+	unsigned int j,jcycle,jj,jpost,jpre,nf,ng=0,ngrid,nn;
+	double **ires[NGMAX+1],**irho[NGMAX+1],**irhs[NGMAX+1],**iu[NGMAX+1];
+
+	nn=n;
+	while (nn >>= 1) ng++;
+	if (n != 1+(1L << ng)) nrerror("n-1 must be a power of 2 in mglin.");
+	if (ng > NGMAX) nrerror("increase NGMAX in mglin.");
+	nn=n/2+1;
+	ngrid=ng-1;
+	irho[ngrid]=dmatrix(1,nn,1,nn);
+	rstrct(irho[ngrid],u,nn);
+	while (nn > 3) {
+		nn=nn/2+1;
+		irho[--ngrid]=dmatrix(1,nn,1,nn);
+		rstrct(irho[ngrid],irho[ngrid+1],nn);
+	}
+	nn=3;
+	iu[1]=dmatrix(1,nn,1,nn);
+	irhs[1]=dmatrix(1,nn,1,nn);
+	slvsml(iu[1],irho[1]);
+	free_dmatrix(irho[1],1,nn,1,nn);
+	ngrid=ng;
+	for (j=2;j<=ngrid;j++) {
+		nn=2*nn-1;
+		iu[j]=dmatrix(1,nn,1,nn);
+		irhs[j]=dmatrix(1,nn,1,nn);
+		ires[j]=dmatrix(1,nn,1,nn);
+		interp(iu[j],iu[j-1],nn);
+		copy(irhs[j],(j != ngrid ? irho[j] : u),nn);
+		for (jcycle=1;jcycle<=ncycle;jcycle++) {
+			nf=nn;
+			for (jj=j;jj>=2;jj--) {
+			for (jpre=1;jpre<=NPRE;jpre++)
+				relax(iu[jj],irhs[jj],nf);
+			resid(ires[jj],iu[jj],irhs[jj],nf);
+			nf=nf/2+1;
+			rstrct(irhs[jj-1],ires[jj],nf);
+			fill0(iu[jj-1],nf);
+			}
+			slvsml(iu[1],irhs[1]);
+			nf=3;
+			for (jj=2;jj<=j;jj++) {
+			nf=2*nf-1;
+			addint(iu[jj],iu[jj-1],ires[jj],nf);
+			for (jpost=1;jpost<=NPOST;jpost++)
+				relax(iu[jj],irhs[jj],nf);
+			}
+		}
+	}
+	copy(u,iu[ngrid],n);
+	for (nn=n,j=ng;j>=2;j--,nn=nn/2+1) {
+		free_dmatrix(ires[j],1,nn,1,nn);
+		free_dmatrix(irhs[j],1,nn,1,nn);
+		free_dmatrix(iu[j],1,nn,1,nn);
+		if (j != ng) free_dmatrix(irho[j],1,nn,1,nn);
+	}
+	free_dmatrix(irhs[1],1,3,1,3);
+	free_dmatrix(iu[1],1,3,1,3);
+}
+#undef NPRE
+#undef NPOST
+#undef NGMAX
+#undef NRANSI