| fe4da5cc |
1 | * |
| 2 | * $Id$ |
| 3 | * |
| 4 | * $Log$ |
| 5 | * Revision 1.1.1.1 1996/02/15 17:50:23 mclareni |
| 6 | * Kernlib |
| 7 | * |
| 8 | * |
| 9 | FUNCTION RNDM (ISEED) |
| 10 | C |
| 11 | C CERN PROGLIB# V104 RNDM .VERSION KERNVAX 2.39 930112 |
| 12 | C ORIG. 22-MAR-88 from IBM version of G.Marsaglia et al., Montreal |
| 13 | C |
| 14 | C !!! Version valid only for VAX floating point format !!! |
| 15 | C Careful: compile with /CHECK=NOOVERFLOW |
| 16 | C |
| 17 | C- Uniform Random Number Generator, |
| 18 | C- giving the same sequence as the IBM and VAX m-language version |
| 19 | |
| 20 | EQUIVALENCE (AMAN,MANT) |
| 21 | PARAMETER (MSK1 = 3072) |
| 22 | C PARAMETER (MSK1 = '00000C00'X) |
| 23 | PARAMETER (MSK2 = 13312) |
| 24 | C PARAMETER (MSK2 = '00003400'X) |
| 25 | SAVE MCGN |
| 26 | DATA MCGN /12345/ |
| 27 | |
| 28 | |
| 29 | MCGN = MCGN * 69069 |
| 30 | MANT = ISHFT (MCGN,-8) |
| 31 | IF (MANT.EQ.0) GO TO 14 |
| 32 | AMAN = MANT |
| 33 | C- AMAN in the range 1 to 2**24-1 |
| 34 | MANT = MANT - MSK1 |
| 35 | C- multiply by 2.**(-24) |
| 36 | RNDM = AMAN |
| 37 | RETURN |
| 38 | |
| 39 | C-- for zero set RNDM = 2.**(-25) |
| 40 | 14 MANT = MSK2 |
| 41 | RNDM = AMAN |
| 42 | RETURN |
| 43 | |
| 44 | C-- Integer random number |
| 45 | ENTRY IRNDM (ISEED) |
| 46 | MCGN = MCGN * 69069 |
| 47 | IRNDM = ISHFT (MCGN,-1) |
| 48 | RETURN |
| 49 | |
| 50 | C-- Set the seed |
| 51 | ENTRY RDMIN (ISEED) |
| 52 | MCGN = ISEED |
| 53 | RETURN |
| 54 | |
| 55 | C-- Get the seed |
| 56 | ENTRY RDMOUT (ISEED) |
| 57 | ISEED = MCGN |
| 58 | END |
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