1The old HS format was highly inefficient, as each piece of data was
2written to its own record. In addition, it only contained information
3about the inter-orbital vectors Xij if k-points were used in the
4calculation.
5
6The new HSX file format was introduced at the time of the first
7COOP/COHP implementation. It is more tightly packed, and the real
8arrays (H, S, and Xij) are written in single-precision.
9
10The HSX format is now the default in Siesta (TranSiesta has its own
11format).
12
13The programs hsx2hs and hs2hsx are provided to facilitate the
14transition. Note however that an HS file written by Siesta during a
15Gamma-only calculation will not contain information about the
16inter-orbital vectors Xij, and hs2hsx will refuse to create an HSX
17file.
18
19hsx2hs and hs2hsx work in serial mode, and read the whole file in
20memory before dumping it. This might pose a problem if huge files are
21processed in low-memory machines.
22
23In future it might be possible to extract the Xij information from
24another file and graft it to the old H and S information, in order to
25create a complete HSX file.
26
27The derived type hsx_t might be useful to encapsulate H, S, and X
28information in other contexts.
29
30The file iohs.F has been moved here from the main source directory.
31
32
33
34