# Quick Overview¶

## Setting up a calculation¶

CONQUEST requires three types of file for a calculation:

• A coordinate file

• Ion files (pseudopotentials)

• The input file (Conquest_input)

### Coordinates¶

CONQUEST works with orthorhombic unit cells (i.e. with angles between lattice vectors at ninety degrees). The coordinate file is laid out simply: lattice vectors, number of atoms, atom coordinates (along with species and movement flags). Either fractional or Cartesian coordinates can be read (the default is fractional; Cartesian coordinates require a flag to be set in the input file). CONQUEST also reads and writes PDB format coordinate files for biomolecular simulations. More information can be found in Coordinates.

### Ion files¶

The ion files contain the pseudopotentials and pseudo-atomic orbitals for the elements, and follow a format similar to the ion files from Siesta (CONQUEST can read Siesta ion files). A set of default inputs to generate ion files is available in the directory pseudo-and-pao. These contain pseudopotentials based on the PseudoDojo library, and allow ion files to be produced with the basis set generation code that is included with CONQUEST in the tools/BasisGeneration directory. Full details are found here.

### Conquest_input¶

The Conquest_input file contains all of the input flags to control a CONQUEST run. At a minimum, the file must specify: the run type (e.g. static or md); the coordinate file name; and the number of species and the ion file names. For a well characterised calculation, further options must be given (for instance setting details for the calculation of the density matrix). Simple examples are given in Example calculations and full documentation of all options can be found in Input tags.

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## Output from a calculation¶

The main output from CONQUEST is in a single file, named Conquest_out by default (this can be changed, and output can be written to stdout rather than a file). This file contains details of the calculation, energies, forces and stresses and the various electronic structure and atomic movement calculations performed. The most important files that are produced during a run are:

• Conquest_out The output file

• Conquest_warnings A list of any warnings issued by the code (also in Conquest_out)

• coord_next.dat The updated set of atomic positions

• conquest.bib References suggested for the calculation performed

• input.log A log of input options (both set by user and defaults)

Other files are produced by different run types, and are discussed elsewhere.