Edit utility

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The underlying philosophy of EosFit is that the data and the data files (.dat) normally should not be modified. For example, the use and omit commands allow you to include and exclude individual data points, or groups of data, without editing the .dat files.


The Edit utility allows you to make changes to the data in a controlled way. Changes can be made to individual data, or all of the data. It works on the entire dataset, not just the parameter (e.g. a or V) chosen for fitting in the main program level. 



When you exit from this Edit utility, the changes that you have made to the data are made available to the main level of the program. They are not saved to a file unless you type write either here, or in the main level. 


If you want to exit without changing the EoS parameters in the main level of the program, type kill.


When you exit for Edit, you must select which cell parameter or unit cell direction to use for analysis in the main program, just as when you read in a dataset from a file.




List of the Edit commands 


Read

Read in data to the program from a .dat file. The file can contain any valid data.

List

List all of the data.

Sort

Sort the data on P, T, or both

Write

Write out the data  to a .dat file

Kill

Exit to the main level of EosFit without saving any changes to the data



Delete

Deletes individual data points from the dataset.

Change

Change data values for a cell parameter or volume and/or its esd's in a linear function. Can be applied to some or all data. The change made is a linear one, for example for the a cell parameters, anew = scale x aold + offfset. The user inputs the values of scale and offset. 



Pshift

Allows you to undo a P-V calibration and apply a new one to adjust pressures. You need the .eos files for the old and new PV calibrations. See example below.

Transform

Transform the unit-cell parameters by a transformation matrix. See example below.

Scale

Set the scale factors for data groups. 


 



Some  of these commands are described in more detail:


Transform command


This command will only work if you have a complete set of unit cell data read in from a data file.


It allows you to transform the unit-cell parameters to a new cell setting. If you have already used transform the new transformation will be applied to the current unit-cell parameters, not the original ones read from file.


There is no 'undo' option (except by doing transform again with the inverse of your first transformation matrix). But you can always read in the dataset again to 'undo' a transformation. Or you can exit from the edit utility with the kill command to delete your changes.


The example on the left is for a triclinic crystal, but you can apply a transform to cell parameters in any crystal system. However, be careful if you break the crystal system symmetry by your transformation!


Type trans to start the command.


The program lists the current unit cell data.


Then you enter the vectors for the new cell axes, one per line, written in terms of the old unit-cell basis vectors. On the left the example sets:

a_new = a_old + c_old

b_new = b_old

c_new = c_old


The program then shows you the transformed cell parameters of the first datum, so that you can check you have input the matrix correctly. If you then answer to the 'is this ok?', the transform will be applied to all of the unit-cells in the dataset.


Note that the esd's of cell parameters cannot be transformed, and therefore they will be set to zero.


Depending from which utility (e.g. edit or the strain utilities) you start the transform command, you may be asked for further input.

Pshift command

 

This command allows you to apply a 're-calibration' of your pressures, if they were determined from a P-V EoS. 


You need both the original EoS used to calculate P from V, and you need the new calibration ready as .eos files. You will be told what to do, and then the INPUT utility will be opened for each file. 


The new pressures are now attached to  the data. If you want to save them permanently to file, use the write command.