CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > Phoenics

Parallel ground coding

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   January 14, 2003, 12:27
Default Parallel ground coding
Phoenics user
Posts: n/a
Can anybody say to me how to introduce new code in ground using parallel phoenics????
  Reply With Quote

Old   January 17, 2003, 12:49
Default Re: Parallel ground coding
Posts: n/a
Parallel PHOENICS operates on a user-specified number of subdomains. These are created automatically by splitting the total solution domain. Each subdomain is assigned to a different parallel processor, and it is enlarged at each edge for which there is a neighbouring subdomain by the addition of two layers of cells. These additional 'overlap' cells are used to store field values from the adjacent subdomains so as to facilitate data exchange between subdomains during the parallel computation. Each processor works only on its own subdomain - and using its own cell numbering system, starting from 1 in each direction.

GROUND coding that only uses current cell values should require no modification to work in parallel mode.

Difficulties may occur where, for instance,

- summations are made over cells that are not in the same subdomain; - references are made to non-neighbour variables that lie (or may lie) in another subdomain; and - references are made to non-neighbour cells by indices rather than physical coordinates.

In the first two cases it is necessary to make use of parallel utility routines to construct the necessary sums, or to exchange values between processors. These are described in the FAQ section of the User Support area on the CHAM web site (available to supported users in possession of a valid maintenance contract).

In the third case it is necessary to change the coding so that the cell indices are derived from the physical coordinates using the available grid information: indices based on the total grid are invalid, as a processor only knows about its own subdomain. This is good practice anyway: even for conventional sequential operation the 'hard-wired' use of cell indices means that any change to the grid will require a corresponding change to the GROUND coding.

More help is available to maintained users in possession of a valid maintenance contract by contacting
  Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Ground Coding Using PLANT Alex Phoenics 1 January 23, 2009 08:52
Help with coding James Main CFD Forum 2 May 18, 2005 06:12
abt Parallel Coding AMV Main CFD Forum 5 April 14, 2003 04:17
Ground coding enquiry Wenqing Zhang Phoenics 2 August 12, 2002 12:56
total pressure without ground coding? Vinod Venugopalan Phoenics 1 May 28, 2002 01:25

All times are GMT -4. The time now is 12:48.