hbfs.for

BFS变度量算法

	SUBROUTINE HBFS(H,N,DELG,DELX,IE)
	DIMENSION H(20,20),DELX(20),DELG(20),HDG(20)
	DGHDG=0.0
	DXG=0.0
	DO 10 I=1,N
	HDG(I)=0.0
	DO 11 J=1,N
11	HDG(I)=HDG(I)+H(I,J)*DELG(J)
	DGHDG=DGHDG+DELG(I)*HDG(I)
10	DXG=DXG+DELX(I)*DELG(I)
	IE=-1
	IF(ABS(DXG).LT.0.1E-60) GO TO 40
	IE=0
	A=1.0+DGHDG/DXG
	DO 3 I=1,N
	DO 3 J=1,N
3	H(I,J)=H(I,J)+(A*DELX(I)*DELX(J)-HDG(I)*DELX(J)-DELX(I)*HDG(J))/DX
     $G
40	RETURN
	END