Pour creer une table lancer le programme ZFSinterppeos
donner la valeur de Z
le fichier de sortie en ASCII est EOSdata.Z
le renommer pr exemple : rename EOSdata.Z eos_130.data.Z
le transformer en binaire par opal_ascii_bin (qui se termine par une division
par 0 car les xx ne sont pas initialises)
il faut indiquer les nons du fichier (eos_130.data) a 2 endroits
dans opal_ascii_bin
.............................................................

4/21/96----- Made changes suggested by V. Baturin in pEOSxtrin.f
             ALSO Fixed grid problem T,P option noted by S. Brun.
4/21/96----- Replaced energy column in pEOSxtrin.f.  Corrects some
             numerical problems found by v. Baturin
3/29/96----- Replaced pEOSxtrin.f.  Problem with irregular grid shape
7/10/95----- The data contained in this directory is identical to
             that in the directory eos at corresponding grid points.  
             However, the grid density in both temperature and 
             density have been increased to allow more accurate
             interpolation.  The smaller tables in the eos directory are
             expected to be suitable for most purposes.
             

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	This directory contains equation of state data files and
corresponding interpolation codes.  The format of the tables is
somewhat different than that used in the opacity directory.  Here the
data is tabulated at constant T6 and density(rho), rather than
constant T6 and R (T6=temperature in units of 10**6 K, R=rho/T6**3),
rho is density in g/cc).

	The data is tabulated at Z=0.0,0.02,and 0.04;
X=0.0,0.2,0.4,0.6 and 0.8. The number of Z and X values is less than
for the opacity tables, due to that fact that the EOS does not vary
as greatly with changes in these variables. The temperature is
tabulated in the range 0.005  to 100.0 and the density in the range
10**(-14) to 10**5 grams/cc.  (Note: much of the region around
rho=10**(-14) is radiation dominated and is included mainly
for convenience of tabulation.)  The lower temperature limit moves
upward for rho > 0.001 gm/cc.  The cut-off at rho=10**5 gm/cc is
determined by the onset of relativistic corrections.  These are well
known for an ideal gas, but their inclusion in the Coulomb
corrections is somewhat more subtle.

	The data files are stored using the compress operation and it
is necessary to apply the uncompress operation before attempting to
use them.  The peos*z%x files are the data files for Z=* and
X=%;i.e., peos02z4x corresponds to Z=0.02 and X=0.4.

	The ZFSinterppeos.f code interpolates the peos*z%x files for a
fixed value of Z, creating a file 'EOSdata'. The EOSdata file is used
by EOSxtrin.f to interpolate in X,T6, and rho at the fixed value of Z
used to construct the EOSdata file.  The accuracy of the
interpolations has been checked by comparison with a large sample of
test calculations.  Better than four place accuracy is generaly achieved
with both first and second order properties.  In regions of rapid change 
the first order properties are occasionally off by as much as  a few %
and the second order properties can be off by 10-20 percent for 
rho=1.e-8.  Larger differences can be expected for rho < 1.e-8 and 
smaller for rho> 1.e-8.  Direct differentiation of the interpolated
first order properties is most likely less accurate and is not recommended.

	Due to the need to calculate derivatives of the EOS, a very
fine temperature-density grid was used.  The tabulated data is a
condensation of this information.  The computer time required to
carry this out for the actual mixture would have been prohibitive, so a
truncated mixture was used.  In the truncated mixture the
mass contribution of all elements above neon where added in with the
neon.  Contrary to the situation with opacity these high Z elements
can never be large contributors to the EOS.  Nevertheless, some small
affects on the derivatives are introduced by this procedure.
The fractional elemental number components of Z are:

		XC= 0.2471362
		XN= 0.0620778
 		XO= 0.528368 
		XNe=0.1624178

The corresponding number fractions are listed at the front of each of
the peos*z%x files.
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The most recent references to this equation of state work is:

Rogers, F.J., Swenson, F.J., Iglesias, C.A. ApJ (submitted)

Rogers,F.J. 1994, in "The Equation of State in Astropyhsics", IAU
Colloquium 147, eds. G. Chabrier and E. Schatzman (Cambridge University
Press), p16

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