Lattimer-Swesty EOS Web Site

Welcome to the LS EOS status page! This page will keep you updated as to the current status of the Lattimer-Swesty Equation of State code.

Changes in the LS EOS up to v2.7

From Version 2.6 to Version 2.7

  1. The 16pt. Gauss-Laguerre quadrature in the full electron EOS was replaced with 64 pt. IMT quadrature (see Natarajan & Kumar, Comp. Phys. Comm., v76, (1993) 48-50) which is much more accurate when the electron or positrons are degenerate. The 16pt. Gauss-Laguerre method can still be accessed by going into the routine EL_EOS and commenting out the section using EL_IMT and commenting in the section using EL_GL.

From Version 2.5 to Version 2.6

  1. No more "fermi.atb" file. The Fermi integral routines now have the spline coefficients data'd in instead of having to read this file. You still must call LOADMX() prior to calling the EOS the first time in order to initialize the boundary & Maxwell construction tables.
  2. The full electron EOS is now incorporated into the code. The code no longer solely uses the relativistic EOS in the LS nuclear physics paper:
                 Nucl. Phys. A, vol. 535, (1991), p.331-376
    The code uses the relativistic electron EOS when appropriate, and computes the full (arbitrarily relativistic) Fermi integrals elsewhere by means of Gauss-Laguere quadrature. The effects of pair production are included everywhere.
  3. The code now expect the boundary & Maxwell contruction files to be named "bound.atb" & "maxwel.atb" and no longer prompts for the file names. My suggestion for handling this is to symbolically link the appropriate *.atb files to these names before starting your code. As an example, suppose you wanted to use the EOS with the K=220 MeV parameter set, then create the symbolic links by typing the commands:
                   ln -s bd180.atb bound.atb
                   ln -s max180.atb maxwel.atb
    before you run the code.

Back to the top of page

Documentation for the LS EOS code

There is a User Guide available to the LS EOS. This guide is available from this web page and is also included in the distribution file. Please read the guide fully before attempting to use the EOS code. It contains some helpfull suggestions about how to incorporate the code into your numerical simulations. Click here if you would like to download a PostScript file ( 80K) of the User Guide.

Back to the top of page

How to get the LS EOS code

To download the version 2.7 of the LS EOS, click on one of the folowing links:

lseos_v2.7.tar for a tarred version (1,516 Kbytes)

lseos_v2.7.tar.Z for a tarred and compressed version (432 Kbytes)

lseos_v2.7.tar.gz for a tarred and gzipped version (319 Kbytes)

lseos_v2.7.tar.uu for a tarred and uuencoded version (2,088 Kbytes)

Back to the top of page

Reporting Bugs

I am always eager to find out about any problems or bugs you may discover in this code. I use this code myself and no one is happier than me to see problems witrh this code eliminated. However, please be aware I may not be able to fix the problems you describe!

Before you report a bug please read the section on "reporting bugs" in the user guide. If you could follow the steps outlined there and provide the information requested I would appreciate it. In particular, please try to isolate the bug using the pnttst routine supplied with the distribution. If you simply send me a message saying "my code crashes when I use your EOS" I won't be able to help you very much.

Many users have reported problems occuring at low temperatures and low values of Ye at subnuclear densities. I am well aware of these problems and wish I could eliminate them! However, these problems do not originate in code bugs. They arise from pathologies in the liquid drop model of the EOS and neither I or Jim Lattimer know how to solve them easily. I am working on ways around this problem and will make the solution available here.

Back to the top of page