Last change
on this file since 1928 was
4,
checked in by raasch, 18 years ago
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Id keyword set as property for all *.f90 files
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Property svn:keywords set to
Id
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File size:
1.6 KB
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1 | FUNCTION random_gauss( idum, upper_limit ) |
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2 | |
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3 | !------------------------------------------------------------------------------! |
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4 | ! Actual revisions: |
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5 | ! ----------------- |
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6 | ! |
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7 | ! |
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8 | ! Former revisions: |
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9 | ! ----------------- |
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10 | ! $Id: random_gauss.f90 4 2007-02-13 11:33:16Z hellstea $ |
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11 | ! RCS Log replace by Id keyword, revision history cleaned up |
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12 | ! |
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13 | ! Revision 1.4 2006/08/04 15:01:48 raasch |
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14 | ! Range of random number is limited by an upper limit (new second parameter) |
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15 | ! |
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16 | ! Revision 1.1 1998/03/25 20:09:47 raasch |
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17 | ! Initial revision |
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18 | ! |
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19 | ! |
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20 | ! Description: |
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21 | ! ------------ |
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22 | ! Generates a gaussian distributed random number (mean value 1, sigma = 1) |
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23 | ! This routine is taken from the "numerical recipies". |
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24 | !------------------------------------------------------------------------------! |
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25 | |
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26 | USE random_function_mod |
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27 | |
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28 | IMPLICIT NONE |
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29 | |
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30 | INTEGER :: idum, iset |
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31 | REAL :: fac, gset, random_gauss, rsq, upper_limit, v1, v2 |
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32 | |
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33 | SAVE iset, gset |
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34 | |
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35 | DATA iset /0/ |
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36 | |
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37 | ! |
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38 | !-- Random numbers are created as long as they do not fall below the given |
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39 | !-- upper limit |
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40 | DO |
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41 | |
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42 | IF ( iset == 0 ) THEN |
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43 | rsq = 0.0 |
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44 | DO WHILE ( rsq >= 1.0 .OR. rsq == 0.0 ) |
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45 | v1 = 2.0 * random_function( idum ) - 1.0 |
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46 | v2 = 2.0 * random_function( idum ) - 1.0 |
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47 | rsq = v1**2 + v2**2 |
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48 | ENDDO |
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49 | fac = SQRT( -2.0 * LOG( rsq ) / rsq ) |
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50 | gset = v1 * fac |
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51 | random_gauss = v2 * fac + 1.0 |
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52 | iset = 1 |
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53 | ELSE |
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54 | random_gauss = gset + 1.0 |
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55 | iset = 0 |
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56 | ENDIF |
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57 | |
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58 | IF ( ABS( random_gauss - 1.0 ) <= upper_limit ) EXIT |
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59 | |
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60 | ENDDO |
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61 | |
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62 | END FUNCTION random_gauss |
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