[u/mrichter/AliRoot.git] / MINICERN / mathlib / gen / v / rg32.F

*
* $Id$
*
* $Log$
* Revision 1.1.1.1  1996/04/01 15:02:55  mclareni
* Mathlib gen
*
*
#include "gen/pilot.h"
#if defined(CERNLIB_VAX)
      OPTIONS/CHECK=NOOVERFLOW
#endif
      FUNCTION RG32(IDUMMY)
#if defined(CERNLIB_CRAY)
CDIR$ INTEGER=64
#endif
C         MACHINE-INDEPENDENT RANDOM NUMBER GENERATOR
C         PRODUCES GAUSSIAN-DISTRIBUTED FLOATING-PT.
C               NUMBERS OF MEAN ZERO AND VARIANCE ONE.
C         IDENTICAL SEQUENCE ON ALL MACHINES OF .GE. 32 BITS.
C              UNIVERSAL VERSION,  F.JAMES, 1985
C              IY     IS THE SEED,
C              CONS   IS 2**-23
C              MASK31 IS 17777777777 OCTAL
      PARAMETER (CONS=1.1920928955078E-07, MASK31=2147483647)
CSELF,IF=-IBM. CERN EDITLIB+SIEMENS COMPILER PROBLEM.
      SAVE IY
CSELF.
      DATA IY/875949887/
C
      JSUM = 0
      DO 50 LOOP= 1, 12
      IY = IY * 69069
C         KEEP ONLY LOWER 31 BITS
      IY = IAND (IY, MASK31)
C         SHIFT RIGHT 8 BITS TO AVOID OVFLO
      JY = IY /256
      JSUM = JSUM + JY
   50 CONTINUE
C         CORRECT FOR TRUNCATION BIAS AND ROUND TO NEAREST
C         EVEN BYTE TO ASSURE EXACT FLOAT
      JSUM = (JSUM+134)/256*256
C
      RG32 = CONS*JSUM - 6.0
      RETURN
C         ENTRY TO INPUT SEED
      ENTRY RG32IN (IDUMMY)
      IY = IDUMMY
      RG32IN = 0.
      RETURN
C         ENTRY TO OUTPUT SEED
      ENTRY RG32OT (IDUMMY)
      IDUMMY = IY
      RG32OT = 0.
      RETURN
      END
Commit	Line	Data
fe4da5cc	1	*
	2	* $Id$
	3	*
	4	* $Log$
	5	* Revision 1.1.1.1 1996/04/01 15:02:55 mclareni
	6	* Mathlib gen
	7	*
	8	*
	9	#include "gen/pilot.h"
	10	#if defined(CERNLIB_VAX)
	11	OPTIONS/CHECK=NOOVERFLOW
	12	#endif
	13	FUNCTION RG32(IDUMMY)
	14	#if defined(CERNLIB_CRAY)
	15	CDIR$ INTEGER=64
	16	#endif
	17	C MACHINE-INDEPENDENT RANDOM NUMBER GENERATOR
	18	C PRODUCES GAUSSIAN-DISTRIBUTED FLOATING-PT.
	19	C NUMBERS OF MEAN ZERO AND VARIANCE ONE.
	20	C IDENTICAL SEQUENCE ON ALL MACHINES OF .GE. 32 BITS.
	21	C UNIVERSAL VERSION, F.JAMES, 1985
	22	C IY IS THE SEED,
	23	C CONS IS 2**-23
	24	C MASK31 IS 17777777777 OCTAL
	25	PARAMETER (CONS=1.1920928955078E-07, MASK31=2147483647)
	26	CSELF,IF=-IBM. CERN EDITLIB+SIEMENS COMPILER PROBLEM.
	27	SAVE IY
	28	CSELF.
	29	DATA IY/875949887/
	30	C
	31	JSUM = 0
	32	DO 50 LOOP= 1, 12
	33	IY = IY * 69069
	34	C KEEP ONLY LOWER 31 BITS
	35	IY = IAND (IY, MASK31)
	36	C SHIFT RIGHT 8 BITS TO AVOID OVFLO
	37	JY = IY /256
	38	JSUM = JSUM + JY
	39	50 CONTINUE
	40	C CORRECT FOR TRUNCATION BIAS AND ROUND TO NEAREST
	41	C EVEN BYTE TO ASSURE EXACT FLOAT
	42	JSUM = (JSUM+134)/256*256
	43	C
	44	RG32 = CONS*JSUM - 6.0
	45	RETURN
	46	C ENTRY TO INPUT SEED
	47	ENTRY RG32IN (IDUMMY)
	48	IY = IDUMMY
	49	RG32IN = 0.
	50	RETURN
	51	C ENTRY TO OUTPUT SEED
	52	ENTRY RG32OT (IDUMMY)
	53	IDUMMY = IY
	54	RG32OT = 0.
	55	RETURN
	56	END