Basic rules

• Warning: Do not expect the input to be logical. The programmers logic may be different from yours.

• Warning: This input description may not refer to the actual version of the program you are using. Therefore the ultimate and authoritative input guide is the source code. Most of the input file is read via the code in the files
  control.F, sysin.F, pi_cntl.F, ratom.F, recpnew.F, dftin.F, proppt.F, respin_p.F, lr_in.F, orbhard.F, cl_init.F and setbasis.F

• The input is free format except when especially stated

• Lines that do not match a keyword are treated as comments and thus ignored.
  Warning: For most sections there will be a report of unrecognized keywords. For the &ATOMS this is not possible, so please check the atom coordinates in the output with particular care .
• Take warnings seriously. There are a few warnings, that can be safely ignored under specific circumstances, but usually warnings are added to a program for a good reason.

• The order of the keywords is arbitrary unless it is explicitly stated. For keywords that select one of many alternatives (e.g. the algorithm for wavefunction optimization), the last one `wins'.

• Only keywords with capital letters match

• Lists inclosed in { } imply that you have to choose exactly one of the items

• Lists inclosed in [ ] imply that you can choose any number of items on the same line

• Arguments to a keyword are given on the following line(s)

• The full keyword/input line has to be within columns 1 to 80

• There are exceptions to those rules.