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Last change
on this file since 2696 was
2696,
checked in by kanani, 6 years ago
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Merge of branch palm4u into trunk
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File size:
1.2 KB
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| 1 | C --- Plain QSSA with fixed step size |
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| 2 | C |
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| 3 | SUBROUTINE INTEGRATE( TIN, TOUT ) |
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| 4 | |
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| 5 | INCLUDE 'KPP_ROOT_params.h' |
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| 6 | INCLUDE 'KPP_ROOT_global.h' |
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| 7 | |
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| 8 | C TIN - Start Time |
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| 9 | KPP_REAL TIN |
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| 10 | C TOUT - End Time |
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| 11 | KPP_REAL TOUT |
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| 12 | |
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| 13 | C Local variables |
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| 14 | KPP_REAL P_VAR(NVAR), D_VAR(NVAR) |
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| 15 | LOGICAL IsReject |
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| 16 | KPP_REAL T, Tnext, STEP, Told, SUP |
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| 17 | KPP_REAL ratio, tmp |
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| 18 | INTEGER i |
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| 19 | |
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| 20 | T = TIN |
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| 21 | Tnext = TOUT |
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| 22 | STEP = 0.1 |
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| 23 | Told = T |
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| 24 | SUP = 1e-14 |
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| 25 | IsReject = .false. |
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| 26 | |
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| 27 | C -- BELOW THIS LIMIT USE TAYLOR INSTEAD OF EXP --- |
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| 28 | |
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| 29 | do while ( T.lt.Tnext ) |
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| 30 | |
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| 31 | if ( T.gt.Tnext ) then |
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| 32 | STEP = Tnext - Told |
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| 33 | T = Tnext |
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| 34 | end if |
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| 35 | |
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| 36 | CALL FSPLIT_VAR ( VAR, P_VAR, D_VAR ) |
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| 37 | |
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| 38 | do i=1,NVAR |
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| 39 | if ( abs(D_VAR(i)).gt.SUP ) then |
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| 40 | ratio = P_VAR(i)/D_VAR(i) |
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| 41 | tmp = exp(-D_VAR(i)*STEP) |
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| 42 | VAR(i) = tmp * (VAR(i) - ratio) + ratio |
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| 43 | else |
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| 44 | tmp = D_VAR(i) * STEP |
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| 45 | VAR(i) = VAR(i) + P_VAR(i) * 0.5 * STEP * ( 1 - 0.5 * tmp * |
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| 46 | * ( 1 - 1.0 / 3.0 * tmp ) ) |
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| 47 | end if |
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| 48 | end do |
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| 49 | |
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| 50 | T = T + STEP |
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| 51 | TIME = T |
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| 52 | |
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| 53 | end do |
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| 54 | |
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| 55 | RETURN |
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| 56 | END |
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