[cig-commits] r6552 - in long/3D/Gale/trunk: . documentation

[walter at geodynamics.org]

Author: walter
Date: 2007-04-12 09:23:17 -0700 (Thu, 12 Apr 2007)
New Revision: 6552

Modified:
   long/3D/Gale/trunk/
   long/3D/Gale/trunk/documentation/gale.lyx
Log:
 r1792 at earth:  boo | 2007-04-12 09:21:41 -0700
 Update the manual



Property changes on: long/3D/Gale/trunk
___________________________________________________________________
Name: svk:merge
   - 3a629746-de10-0410-b17b-fd6ecaaa963e:/cig:1790
   + 3a629746-de10-0410-b17b-fd6ecaaa963e:/cig:1792

Modified: long/3D/Gale/trunk/documentation/gale.lyx
===================================================================
--- long/3D/Gale/trunk/documentation/gale.lyx	2007-04-12 15:43:29 UTC (rev 6551)
+++ long/3D/Gale/trunk/documentation/gale.lyx	2007-04-12 16:23:17 UTC (rev 6552)
@@ -2053,7 +2053,15 @@
  Before trusting any results you get from Gale, you must vary a number of
  parameters to insure that the results are not an artifact of Gale's approximati
 ons.
- Specifically, for every simulation, vary the resolution (
+ The most important parameter is the resolution.
+\end_layout
+
+\begin_layout Standard
+In Gale, there are two kinds of resolution: grid and particles.
+ The grid is where the stokes equations are solved, and define the resolution
+ of everything in the "fields" and "pressure" output files (e.g.
+ velocity, pressure, strain rate, etc.).
+ The resolution of the grid is determined by 
 \family typewriter
 elementResI
 \family default
@@ -2061,15 +2069,54 @@
 \family typewriter
 elementResJ
 \family default
+, and 
+\family typewriter
+elementResK
+\family default
+.
+\end_layout
+
+\begin_layout Standard
+The particles carry material information.
+ So if you have a smooth velocity field, but a complex particle properties
+ field, then you would need a greater ratio of particles to grid points.
+ The resolution of the particles is expressed in terms of the number of
+ particles per grid cell.
+ So increasing the grid resolution automatically increases the particle
+ resolution proportionately.
+ To further modify the particle resolution, change the parameter 
+\family typewriter
+particlesPerCell
+\family default
+.
+\end_layout
+
+\begin_layout Standard
+So for every simulation, you need to vary the grid resolution (
+\family typewriter
+elementResI
+\family default
 , 
 \family typewriter
+elementResJ
+\family default
+, 
+\family typewriter
 elementResK
 \family default
-) and the number of particles in each element (
+) and the particles resolution (
 \family typewriter
 particlesPerCell
 \family default
 ).
+\end_layout
+
+\begin_layout Standard
+In addition, you need to vary the scaling factor for time steps (
+\family typewriter
+dtFactor
+\family default
+).
  For problems with inflow boundaries (see Sections 
 \begin_inset LatexCommand \ref{sec:Viscous-In-Outflow}
 
@@ -2081,8 +2128,8 @@
 \end_inset
 
 ), you must vary the size of the boundary box.
- In addition, depending on the boundary conditions, you may need to vary
- the size of the box (
+ Depending on the boundary conditions, you may need to vary the size of
+ the box (
 \family typewriter
 minX
 \family default
@@ -2118,6 +2165,12 @@
  component).
 \end_layout
 
+\begin_layout Standard
+How much to vary the various parameters depends upon each parameter.
+ In general, changing each parameter by a factor of two should give you
+ a good enough idea of how much the simulation depends on that parameter.
+\end_layout
+
 \begin_layout Chapter
 Cookbooks
 \begin_inset LatexCommand \label{cha:Cookbooks}
@@ -2894,8 +2947,8 @@
  The current example is not intended to be geologically realistic in any
  sense, but is meant to illustrate the enormous flexibility we have in the
  development of complex boundary conditions.
- A more realistic model of subduction is included in the sample input file
- 
+ This type of boundary condition is useful for subduction models, an example
+ of which is in 
 \family typewriter
 input/subduction.xml
 \family default
@@ -5193,6 +5246,7 @@
 \begin_layout Description
 gaussParticlesX,gaussParticlesY,gaussParticlesZ The number of particles
  in each direction when putting down particles using a Gaussian distribution.
+ This is used when mapping quantities from the particles to the grid.
  You should never need to change this number.
 \end_layout
 
@@ -5204,6 +5258,24 @@
  simulation are to this number.
 \end_layout
 
+\begin_layout Description
+dtFactor A factor to scale the time step.
+ Ordinarily, Gale will automatically choose an appropriate step size to
+ ensure a stable solution.
+ If Gale is choosing too large of a step size, you can change 
+\family typewriter
+dtFactor
+\family default
+ to a smaller number.
+ The default is 1 (no scaling).
+\end_layout
+
+\begin_layout Description
+seed A random number seed used when placing new particles.
+ You should never need to change this, and changing this should not affect
+ the simulation.
+\end_layout
+
 \begin_layout Section
 Basic Components
 \begin_inset LatexCommand \label{sec:Basic-Components}