Changeset 197 for palm/trunk/DOC/app/chapter_4.2.html

Timestamp:

Sep 16, 2008 3:29:03 PM (16 years ago)

Author:

raasch

Message:

further adjustments for SGI and other small changes

File:

• palm/trunk/DOC/app/chapter_4.2.html (modified) (9 diffs)

palm/trunk/DOC/app/chapter_4.2.html

@@ -2575 +2575 @@
 
 
- <tr>
+ <tr><td align="undefined" valign="undefined"><span style="font-style: italic; color: rgb(255, 0, 0);">p</span></td><td align="undefined" valign="undefined">Perturbation pressure (in Pa)</td></tr><tr>
 
 
@@ -3717 +3717 @@
 assigned. This
 yields a loss of accuracy, but the file size is clearly reduced. The
-parameter <a href="chapter_4.2.html#do3d_precision">do3d_precision</a>
+parameter <a href="chapter_4.2.html#do3d_comp_prec">do3d_comp_prec</a>
 can be used to separately define the number of significant digits for
 each quantity.<br>
@@ -3747 +3747 @@
       
       
-      <p><a name="do3d_precision"></a><b>do3d_precision</b></p>
+      <p><a name="do3d_comp_prec"></a><b>do3d_comp_prec</b></p>
 
 
@@ -3817 +3817 @@
       
       
-      <p>The default assignment is <span style="font-weight: bold;">do3d_precision</span>
+      <p>The default assignment is <span style="font-weight: bold;">do3d_comp_prec</span>
 = <span style="font-style: italic;">'u2'</span>, <span style="font-style: italic;">'v2'</span>, <span style="font-style: italic;">'w2'</span>, <span style="font-style: italic;">'p5'</span>, <span style="font-style: italic;">'pt2'</span>.</p>
 
@@ -4817 +4817 @@
 
             <td style="vertical-align: top;">Subgrid-scale sensible
-heat flux near the surface (horizontal
-average)
-between z = 0 and z = z<sub>p</sub> = zu(1) (there it
-corresponds to
-the total heat flux) (in K m/s).</td>
+heat flux at k=0 (horizontal
+average), constant within Prandtl-layer (in K m/s).</td>
 
 
@@ -4856 +4853 @@
 
 
- <tr>
+ <tr><td align="undefined" valign="undefined"><span style="font-style: italic;">w"u"0</span></td><td align="undefined" valign="undefined">Subgrid-scale momentum flux (u-component) at k=0 (horizontal average), constant within Prandtl-layer (in m<sup>2</sup>/s<sup>2</sup>).</td></tr><tr><td align="undefined" valign="undefined"><span style="font-style: italic;">w"v"0</span></td><td align="undefined" valign="undefined">Subgrid-scale momentum flux (v-component) at k=0 (horizontal average), constant within Prandtl-layer (in m<sup>2</sup>/s<sup>2</sup>).</td></tr><tr><td align="undefined" valign="undefined"><span style="font-style: italic;">w"q"0</span></td><td align="undefined" valign="undefined">Subgrid-scale
+humidity flux at k=0 (horizontal average), constant within
+Prandtl-layer (in kg/kg m/s). Zero values are output if humidity is not
+used.</td></tr><tr>
 
 
@@ -4886 +4886 @@
 
 
- <tr>
-
-
-
-            <td style="vertical-align: top; font-style: italic;">splptx</td>
-
-
-
-            <td style="vertical-align: top;">Percentage of grid points
-using upstream scheme along x with
-upstream-spline advection switched on.</td>
-
-
- </tr>
-
-
- <tr>
-
-
-
-            <td style="vertical-align: top; font-style: italic;">splpty</td>
-
-
-
-            <td style="vertical-align: top;">Percentage of grid points
-using upstream scheme along y with
-upstream-spline
-advection switched on.</td>
-
-
- </tr>
-
-
- <tr>
-
-
- <td style="vertical-align: top; font-style: italic;">splptz</td>
-
-
-
-            <td style="vertical-align: top;">Percentage of grid points
-using upstream scheme along z with
-upstream-spline
-advection switched on.<br>
-
-
- </td>
-
-
- </tr>
+ 
+
+
+ 
+
+
+ 
 
 
@@ -5640 +5597 @@
 It is only possible to gather data from a level larger than the one
 determined automatically. A test run may be neccessary to determine
-this level.</td>
+this level.<br><br>Setting of <span style="font-weight: bold;">mg_switch_to_pe0_level</span> = <span style="font-style: italic;">-1</span> prevents that data are collected on PE0 at all, i.e. coarsening of grids is limited by the subdomains.</td>
 
 
@@ -5848 +5805 @@
 
 
- <tr>
+ <tr><td style="vertical-align: top;"><a href="npex"><span style="font-weight: bold;"></span></a><span style="font-weight: bold;"><a name="npex"></a>npex</span></td><td style="vertical-align: top;">I</td><td style="vertical-align: top;"></td><td style="vertical-align: top;"><p>Number of processors
+along x-direction of the virtual
+processor
+net.&nbsp; </p>
+
+
+
+
+
+
+ 
+      
+      
+      
+      
+      
+      
+      <p>For parallel runs, the total
+number of processors to be used
+is given by
+the <span style="font-weight: bold;">mrun</span>
+option <a href="http://www.muk.uni-hannover.de/software/mrun_beschreibung.html#Opt-X">-X</a>.
+By default, depending on the type of the parallel computer, PALM
+generates a 1d processor
+net (domain decomposition along x, <span style="font-weight: bold;">npey</span>
+= <span style="font-style: italic;">1</span>) or a
+2d-net (this is
+favored on machines with fast communication network and/or large number of processors (&gt;256)). In case of a
+2d-net, it is tried to make it more or less square-shaped. If, for
+example, 16 processors are assigned (-X 16), a 4 * 4 processor net is
+generated (<span style="font-weight: bold;">npex</span>
+= <span style="font-style: italic;">4</span>, <span style="font-weight: bold;">npey</span>
+= <span style="font-style: italic;">4</span>).
+This choice is optimal for square total domains (<a href="chapter_4.1.html#nx">nx</a>
+= <a href="chapter_4.1.html#ny">ny</a>),
+since then the number of ghost points at the lateral boundarys of
+the subdomains reaches a minimum. If <span style="font-weight: bold;">nx</span>
+and <span style="font-weight: bold;">ny</span>
+differ extremely, the
+processor net should be manually adjusted using adequate values for <span style="font-weight: bold;">npex</span> and <span style="font-weight: bold;">npey</span>.&nbsp; </p>
+
+
+
+
+
+
+
+      
+      
+      
+      
+      
+      
+      <p><b>Important:</b> The value of <span style="font-weight: bold;">npex</span> * <span style="font-weight: bold;">npey</span> must exactly match the
+value assigned by the <span style="font-weight: bold;">mrun</span>-option
+      <tt>-X</tt>.
+Otherwise the model run will abort with a corresponding error
+message.&nbsp; <br>
+
+
+
+
+
+
+
+Additionally, the specification of <span style="font-weight: bold;">npex</span>
+and <span style="font-weight: bold;">npey</span>
+may of course
+override the default setting for the domain decomposition (1d or 2d)
+which may have a significant (negative) effect on the code performance.
+      </p></td></tr><tr><td style="vertical-align: top;"><span style="font-weight: bold;"><a name="npey"></a>npey</span></td><td style="vertical-align: top;">I</td><td style="vertical-align: top;"></td><td style="vertical-align: top;"><p>Number of processors
+along y-direction of the virtual
+processor
+net.&nbsp; </p>
+
+
+
+
+
+
+ 
+      
+      
+      
+      
+      
+      
+      <p>For further information see <a href="chapter_4.2.html#npex">npex</a>.</p></td></tr><tr>