Data file format

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  • The datafile is never over-written by the program except when you do so with the write command. 
  • Default extension for the data file is *.dat but users can choose any other extension (see file types)
  • The format is very flexible. 
  • Only a few keywords are used.
  • Any blank line, or any line starting with # is ignored.
  • Data appear in the files after the keyword Data



KEYWORDS LIST


Keywords

Comments

Title  string

Allows a title to be put on the file that will be reported in the output files.



Ex.: Title Kalsilite at High Pressure

Comment string

Any blank line, or any line starting with # is ignored by the program, but allow you to annotate the file (see example datasets). It will not be reported in the output file.

System key

If the crystal is of higher symmetry than triclinic this may be specified . In this case, only the symmetry-independent unit cell parameters have to be given (see example datasets).


Keys

Monoclinic

Orthorhombic

Tetragonal

Trigonal

Hexagonal

Cubic


If no volume is given in the data, then the program will use the crystal system to calculate the volume and it's esd, if enough information is given in the input file.



Ex.: System hexagonal

Tscale key

If the data points include temperature information, use this to specify the temperature scale.


Keys


K

Kelvin

C

Centigrade

F

Fahrenheit


If Tscale is not given, any temperatures will be assumed to be Kelvin. The programs work in Kelvin, and temperatures input on the other scales are immediately converted to Kelvin.


Ex.: System Tscale C

Pscale key

The name of the pressure scale of the data, for example 'GPa' or 'kbar'


In general no specific names required, but thermal pressure EoS and the APL PV EoS only work correctly if the pscale is set to kbar or GPa and the data have pressures in these units.


If units are also given for the bulk modulus in the EoS, then EosFit-7c will check for consistency and issue a warning if the scales of the data and the EoS do not agree.



Vscale key

The name of the volume scale of the data, for example 'A^3/cell' or 'cm^3/mol'


There are no specific names required, but thermal pressure EoS  only work correctly if the data are in cm^3/mol and the vscale key in the data file is set to this. The APL EoS requires data in A^3.


If units are also given for the volume in the EoS, then EosFit-7c will check for consistency and issue a warning if the scales of the data and the EoS do not agree.




Lscale key

The name of the length scale of the data for linear dimensions (e.g. cell parameters), for example 'A/cell' or 'A'


 There are no specific names required. If the datafile contains both volumes and cell parameters, you can put in both the lscale and vscale keywords.



Datatype key

Only works with Eosfit7c, not the GUI.


Indicates the type of data in the file. Not required for unit-cell parameters, or volumes. Required for moduli data. 


Important: you cannot mix data types in one file. If you want to refine to both volume and moduli data, create two data files and load them separately. See  the file quartz_moduli.dat in the example datasets  and the worked example for quartz.


Keys


moduli

data are elastic moduli

adiabatic

data are adiabatic moduli

isothermal

data are isothermal moduli


If Datatype is not given, all data will be assumed to be unit-cell and volume data.


If you use moduli, you must always specify one of adiabatic or isothermal:

for example: Datatype adiabatic moduli





Format N key1 key2...

Specify the format of the data.


N specify how many lines are provided for each data point. For example, 1 means one line per datum.


Keys  specify the order of data on the line.


Keys


P

Pressure

T

Temperature

V

Volume

A


B


C

Cell parameters

ALPHA


BETA


GAMMA


SIGP


SIGT


SIGV


SIGA

Respective sigma values

SIGB


SIGC


SIGAL


SIGBE


SIGGA



Ex.: Format  1  P  SigP  A  SigA   C  SigC

In case standard deviation are given in parenthesis it doesn't need to be specified in the format line (see example datasets)

Important: you cannot mix the two ways of giving esd's in one data file!


Note that old-style, version 5.2,  format labels are also still supported.





Data input


All lines after the format line are interpreted as data lines. The order in which the data 

such as P, V or T appear in each line must be always the same as specified by the format line. 

At minimum you must have either P and V or V and T. The uncertainties in P, V or T are optional, 

but recommended.


Data values can be separated by spaces or commas or tabs. Files with data values separated by tabs are not read correctly by some Mac systems in some languages.



There is no special end line for the data. The last line of the file must be a data line,

not a blank line.