Changes between Version 46 and Version 47 of doc/app/chemistry_parameters

Timestamp:

Oct 15, 2018 11:27:44 AM (6 years ago)

Author:

forkel

Comment:

--

doc/app/chemistry_parameters

@@ -345 +345 @@
 }}}
 {{{#!td
-Selection and steering of the chemistry solver. 
+Selection and steering of the chemistry solver. In order to offer more control over the integrator, the KPP-generated Integrator subroutine (e.g. SUBROUTINE rosenbrock in chem_gasphase_mof.f90) provides the optional input parameters ICNTRL_U and RCNTRL_U. Each of them is an array of 20 elements that allow the fine-tuning of the integrator, e.g. by setting a particular Integrator method, tolerances, minimum and maximum step sizes, etc. 
 
 Note: For input parameters equal to zero the default values of the corresponding variables are used.\\
@@ -351 +351 @@
     ICNTRL(1) = 1: F = F(y)   Independent of T (AUTONOMOUS), = 0: F = F(t,y) Depends on T (NON-AUTONOMOUS)
 
-    ICNTRL(2) = 0: AbsTol, RelTol are N-dimensional vectors, = 1: AbsTol,RelTol are scalars
-
-    ICNTRL(3)  -> selection of a particular Rosenbrock method
-         0 :    Rodas3 (default)
-         1 :    Ros2
-         2 :    Ros3
-         3 :    Ros4
-         4 :    Rodas3
+    ICNTRL(2) = 0: abstol, reltol are N-dimensional vectors, = 1: Abstol, Reltol are scalars
+
+    ICNTRL(3)  -> selection of a particular Rosenbrock method\\
+         0 :    Rodas3 (Default from KPP)\\
+         1 :    Ros2 (Simplest Rosenbrock solver, will also do)\\
+         2 :    Ros3\\
+         3 :    Ros4\\
+         4 :    Rodas3\\ 
          5 :    Rodas4
 
     ICNTRL(4)  -> maximum number of integration steps; For ICNTRL(4) =0) the default value of 100000 is used
+
+Example:\\
+    icntrl(3)                  = 1,   ! ros2 (a bit less time consuming than the Rodas3 solver recommended by KPP) \\
+    icntrl(4)                  = 500, ! berlin setup  max. number of chem-substeps\\
 
 See http://people.cs.vt.edu/asandu/Software/Kpp/
@@ -457 +461 @@
 Steering of the chemistry solver.
 
-RCNTRL(1)  -> Hmin,lower bound for the integration step size. It is strongly recommended to keep Hmin = ZERO
-
-RCNTRL(2)  -> Hmax,upper bound for the integration step size
-
-RCNTRL(3)  -> Hstart,starting value for the integration step size
-
-RCNTRL(4)  -> FacMin (lower bound on step decrease factor, default=0.2); RCNTRL(5)  -> FacMax (upper bound on step increase factor, default=6); RCNTRL(6)  -> FacRej (step decrease factor after multiple rejections)
-
-RCNTRL(7)  -> FacSafe (by which the new step is slightly smaller than the predicted value, default=0.9)
+RCNTRL(1)  -> Hmin, lower bound for the integration step size. It is strongly recommended to keep Hmin = ZERO
+
+RCNTRL(2)  -> Hmax, upper bound for the integration step size
+
+RCNTRL(3)  -> Hstart, starting value for the integration step size
+
+RCNTRL(4)  -> Facmin (lower bound on step decrease factor, default=0.2)
+
+RCNTRL(5)  -> Facmax (upper bound on step increase factor, default=6)
+
+RCNTRL(6)  -> Facrej (step decrease factor after multiple rejections)
+
+RCNTRL(7)  -> Facsafe (by which the new step is slightly smaller than the predicted value, default=0.9)
 
 See http://people.cs.vt.edu/asandu/Software/Kpp/
+
+Example:\\
+    rcntrl(3)                  = 0.1, ! hstart in sec. Setting of hstart can result in savoings of computstinal time of 30% and more.
+
 }}}
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