c2x and Siesta

Siesta is a GPLed linear-scaling DFT code.

Reading

From version 2.14a, c2x can read much of the syntax of Siesta's .fdf (flexible data format) input files. In most cases it can read the cell, atom positions, and initial colinear spins. It supports .fdf's include file syntax, both %includefile and <, regarding paths as relative to the current directory, not the directory of the file being processed.

When specifying initial colinear spins, + is interpreted as +1, not maximum possible spin, and similarly -.

Writing

c2x has always been able to write .fdf files. Support for colinear spins was added in 2.14a.