[u/mrichter/AliRoot.git] / GEANT321 / gstrag / gstint.F

*
* $Id$
*
* $Log$
* Revision 1.1.1.1  1995/10/24 10:21:39  cernlib
* Geant
*
*
#include "geant321/pilot.h"
*CMZ :  3.21/02 29/03/94  15.41.25  by  S.Giani
*-- Author :
      FUNCTION GSTINT(X,A,F,N)
*
*       Simple linear interpolation
*
      DIMENSION A(N),F(N)
      DATA K1,K2,NO/0,0,0/
*
*       Check (N==NO) & (A(K1)<X<A(K2))
*
      IF (N.NE.NO.OR.A(K1).GT.X.OR.X.GT.A(K2)) THEN
*
*       Skip Unless N>1
*
         IF (N.LE.1) THEN
            GSTINT=F(1)
            GO TO 999
         ENDIF
         K1=1
         K2=N
         NO=N
*
*       Loop over K2-K1>1
*
  10     K=(K1+K2)/2
*
*       Check A(K)<X
*
         IF (A(K).LT.X) THEN
            K1=K
         ELSE
            K2=K
         END IF
         IF(K2-K1.GT.1) GO TO 10
      END IF
      X1=A(K1)
      X2=A(K2)
      GSTINT=(F(K1)*(X-X2)+F(K2)*(X1-X))/(X1-X2)
*
 999  END
Commit	Line	Data
fe4da5cc	1	*
	2	* $Id$
	3	*
	4	* $Log$
	5	* Revision 1.1.1.1 1995/10/24 10:21:39 cernlib
	6	* Geant
	7	*
	8	*
	9	#include "geant321/pilot.h"
	10	*CMZ : 3.21/02 29/03/94 15.41.25 by S.Giani
	11	*-- Author :
	12	FUNCTION GSTINT(X,A,F,N)
	13	*
	14	* Simple linear interpolation
	15	*
	16	DIMENSION A(N),F(N)
	17	DATA K1,K2,NO/0,0,0/
	18	*
	19	* Check (N==NO) & (A(K1)<X<A(K2))
	20	*
	21	IF (N.NE.NO.OR.A(K1).GT.X.OR.X.GT.A(K2)) THEN
	22	*
	23	* Skip Unless N>1
	24	*
	25	IF (N.LE.1) THEN
	26	GSTINT=F(1)
	27	GO TO 999
	28	ENDIF
	29	K1=1
	30	K2=N
	31	NO=N
	32	*
	33	* Loop over K2-K1>1
	34	*
	35	10 K=(K1+K2)/2
	36	*
	37	* Check A(K)<X
	38	*
	39	IF (A(K).LT.X) THEN
	40	K1=K
	41	ELSE
	42	K2=K
	43	END IF
	44	IF(K2-K1.GT.1) GO TO 10
	45	END IF
	46	X1=A(K1)
	47	X2=A(K2)
	48	GSTINT=(F(K1)(X-X2)+F(K2)(X1-X))/(X1-X2)
	49	*
	50	999 END