3. Input variables

The pw.x and ph.x input files are described in the QUANTUM ESPRESSO documentation. In this section we discuss only the creation of the file thermo_ control. This file contains a namelist:

&INPUT_THERMO
  what=' ',
  ...
 /

The what variable controls the sequence of calculations made by THERMO_PW. For each possible value of what, we discuss briefly the input variables that control the output plots. Usually default values of the input variables are sufficient to carry out the basic THERMO_PW tasks and you are not supposed to set any variable except what, but in some cases these input variables give more control on the calculation and on its accuracy.

THERMO_PW writes on files the data to plot and a script to plot these data. The output postscript or pdf files are produced by invoking the gnuplot program. Usually any modern Linux distribution provides a package to install this code, or has it already installed. You can also download the package from http://www.gnuplot.info/.
The following input variables control the use of the gnuplot code:

lgnuplot    : if .TRUE. gnuplot is called by the 
              program and the postscript or pdf files are 
              immediately available. Otherwise give the 
              command gnuplot gnuplot_files/*.
              Default: logical .TRUE.
gnuplot_command  : the command used to call gnuplot.
              Default: character(len=*) 'gnuplot'
flgnuplot   : initial part of the name of the files where 
              gnuplot scripts are written.
              Default: character(len=*) 'gnuplot.tmp'
flext       : extension of the output files. Presently .ps 
              and .pdf are supported for postscript or pdf 
              output. The latter is available only if gnuplot 
              supports the pdfcairo terminal.
              Default: character(len=*) '.ps'

If your system has not gnuplot you can disable the production of the postscript or pdf files and use other graphical tools to plot the output data.