4.9 KiB
A Modern Fortran-based Parser
This repository contains a modern Fortran-based input file parser. It uses a modified libfdf library.
Get the code
The library is included in this repository as a submodule. To clone the entire project, do
git clone --recurse-submodules https://github.com/TREX-CoE/fparser.git
Compilation
The project contains two folders (a) modified-libfdf and (b) parser.
Compile and install the modified-libfdf using the following set of commands
./configure --prefix=/usr/local FC=ifort CC=icc
make
sudo make install
In the parser folder, link the modified libfdf library with the interface Fortran file.
ifort -c interface.F90 m_keywords.F90 m_periodic_table.F90 /usr/local/lib/libfdf.a
Integrate parser in your code
Just include the interface.F90 file and the keyword declaration module files in the existing Makefile of your code.
Features of the parser (including inheritance from libfdf)
Blank lines and lines starting with # are ignored.
The order of keyword-value pairs does not matter
Multiple keyword-value pairs can be put in a single line
Keywords are case insensitive.
A default value can be set for keywords not present in the input file.
Syntax
Include another input file for parser to read using:
%include global.inp
Include a data file for parser to read using:
load label filename
Here, depending upon the label, parser will provide the filename. For example,
load basis cc-pvtz.gbs
Read molecular coordinates directly from the input file using
%block molecule 12 #benzene comment 0.00000 1.40272 0 C 0.00000 2.49029 0 H 1.21479 0.70136 0 C -2.15666 1.24515 0 H -1.21479 -0.70136 0 C -2.15666 -1.24515 0 H -0.00000 -1.40272 0 C 0.00000 -2.49029 0 H 1.21479 -0.70136 0 C 2.15666 -1.24515 0 H 1.21479 0.70136 0 C 2.15666 1.24515 0 H %endblock
Read molecular coordinates from an external .xyz file using
%block molecule < benzene.xyz
Group certain keywords using the %module construct
%module DMC 0.04 tau = 15 Ha etrial = -%endmodule
Logical variables accept
true
,TRUE
,T
,.true.
as valid keywords forTrue
. Thefdf_boolean
function can also take “1” as true and “0” as false from the input.optimize_wavefunction true
Single and Double precision numbers along with numbers in scientific format can be read using the
fdf_get()
function.energy_tol = fdf_get('energy_tol', 0.00001d0)
Floats/integers/strings/booleans can be parsed generically using the interface
fdf_get()
function. Strings are limited to 132 characters per line.sr_tau = fdf_get('sr_tau', 0.025d0)
nspin1 = fdf_get('nspin1', 1)
opt_method = fdf_get('opt_method', "sr_n")
multiple_adiag = fdf_get('multiple_adiag', .false.)
Units can be specified to variables. Unit conversion is possible at the parsing.
If the input file has
etrial = -15 Ha
entry, theetrial
variable can be assigned values using thefdf_physical
function with unit conversion.etrial = fdf_physical('etrial', -20.d0, 'eV')
List of public functions available for parsing the data:
Initiate
fdf_init
fdf_shutdown
Single data
fdf_get
fdf_integer
fdf_single
fdf_double
fdf_string
fdf_boolean
fdf_physical
fdf_convfac
fdf_load_filename
Lists (data enclosed in [])
fdf_islist
fdf_islinteger
fdf_islreal
fdf_list
fdf_linteger
fdf_ldouble
Returns the string associated with a mark line
fdf_getline
Test if a label is defined
fdf_defined
fdf_isphysical
fdf_isblock
fdf_load_defined
Allow to overwrite things in the FDF
fdf_overwrite
fdf_removelabel
fdf_addline
Block reading (processing each line of data)
fdf_block, fdf_block_linecount
fdf_bline, fdf_bbackspace, fdf_brewind, fdf_bclose
fdf_bnintegers, fdf_bnreals, fdf_bnvalues, fdf_bnnames, fdf_bntokens
fdf_bintegers, fdf_breals, fdf_bvalues, fdf_bnames, fdf_btokens
fdf_bboolean, fdf_bphysical
fdf_bnlists, fdf_bnilists, fdf_bnrlists, fdf_bnvlists
fdf_bilists, fdf_brlists, fdf_bvlists
Match, search over blocks, and destroy block structure
fdf_bmatch, fdf_bsearch, fdf_substring_search
fdf_setoutput, fdf_setdebug
Demonstration
In the `parser` folder, we have included a sample `interface.F90` and `m_keywords.F90` files.
In the `interface.F90` file, we have demonstrated how keyword-values pairs, simple data blocks,
and data from external files can be read easily.