LSS Utility

LSS is a program that computes nodal stream function values from a velocity field, suitable for visualization in EnSight or pV3. The weak form being solved is:

Unlike LSV, the least-squares system must be solved accurately using the GMRES solver with a sufficient number of iterations.

Documentation

This is it, and you can also look at the source code in the lss CVS module. The file parseinput.F can be helpful in identifying all current options, and the initialize.F will show you some of the default values.

Data Requirements

LSV reads standard 2D MIXD format data files. The files should be pure IEEE binary, 64-bit floating point, node-level. For more information on writing pure binary files see the EWD library documentation.

System Requirements

LSS has been so far compiled on IRIX 6.x.

Usage

LSS executable resides typically in /usr/local/bin/lss. When run interactively, it looks for a lss.in input file in the current directory, and if it is found, accepts the command input from there. If that file does not exist, the commands are read from the standard input. Alternatively, the input can be redirected from an arbitrary file. There are no command line options at the moment. The program produces one degree of freedom.

Input

LSS accepts the following keywords as commands.
Key values can be integer %d, floating point %f and strings without spaces %s.

Key	Description	Example	Default
`abort`	aborts the program	`abort`	`-`
`source %s`	temporarily switches command input to another file	`source minf`	`-`
`iquad %d`	quadrature code	`iquad 1`	`2`
`nsd %d`	number of spatial dimensions	`nsd 2`	`2`
`nen %d`	number of element nodes	`nen 3`	`4`
`ndf %d`	number of degrees of freedom per node	`ndf 6`	`3`
`ne %d`	number of mesh elements	`ne 396682`	`-`
`nn %d`	number of mesh nodes	`nn 139352`	`-`
`nrec %d`	number of data and/or coordinate records	`nrec 20`	`1`
`minrec %d`	nstarting data and/or coordinate record	`minrec 2`	`1`
`maxrec %d`	ending data and/or coordinate record	`maxrec 18`	`nrec`
`increc %d`	data and/or coordinate record increment	`increc 2`	`1`
`onerec %d`	single record number	`onerec 18`	`-`
`udf %d`	x-velocity degree of freedom	`udf 2`	`1`
`vdf %d`	y-velocity degree of freedom	`vdf 3`	`2`
`wdf %d`	z-velocity degree of freedom	`wdf 4`	`3`
`ninner %d`	Kyrlov space size for GMRES	`ninner 50`	`20`
`nouter %d`	number of GMRES restarts	`nouter 4`	`1`
`dir %s`	default directory	`dir /work`	`.`
`mien %s`	file name containing connectivity array	`mien /tmp/mien`	`mien`
`mxyz %s`	file name containing nodal coordinates	`mxyz /tmp/mxyz.space`	`mxyz`
`data %s`	file name containing nodal data	`data /tmp/do.0048`	`data`
`stream %s`	file name for placing vorticity	`mrng /tmp/stream`	`stream`

Sample Input

As an example, consider the input file listed below:

hydra(test)% cat lss.in
source minf.space
mxyz mxyz.space
data do.1e7.0500
stream so.1e7.0500
 
debug on
moving on
ndf 3
nrec 5

This would create a stream function file so.1e7.0500 suitable for analysis with Pager or EnSight.

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