CASINO manual - Theory of Condensed Matter

an error which may take two weeks of your life to track down (and this could be much better spent
doing other things). You can get the idea just by looking at the developer version source code in
CASINO/src (the standard version is ‘obfuscated’ and practically unreadable) but let’s emphasize the
main points:
• Don’t use more than one module per physical file, as Hitachi compilers won’t (or didn’t used
to) allow this!
• Capitalization outside of character context: use upper-case letters for keywords whose use is
primarily at compile time (statements that delimit program and subprogram boundaries, declaration
statements of variables). Use lower-case letters for everything else, including the bulk
of run-time code. Description of routines is to be enclosed in a little box with a description of
what it does and an author. Later changes are to be documented at the bottom of this box. For
example:
SUBROUTINE rubbish
!-------------------------------------------------------------------------!
! Routine to write words to the screen. !
! !
! MDT 8.2000 !
! !
! Changes: !
! -------- !
! 3/2001 MDT - added capability to write ‘Hello’ !
! 5/2001 MDT - added additional capability to write ‘Donkey!’ !
!-------------------------------------------------------------------------!
USE dsp
USE parallel
IMPLICIT NONE
INTEGER i,j,k,some_integer
REAL(dp) a
CHARACTER(llength)my_name
i=0
do j=1,10
write(6,*)’Hello’
do k=1,1000000
i=i+1
write(6,*)’Donkey!’
enddo
enddo
! etc.
END SUBROUTINE rubbish
• Contents of if, do and case blocks should be indented by one space.
• In general don’t put spaces between words, e.g.,
if(something_is_true)a=b+c
not
if ( something_is_true ) a = b + c
• Do not use ‘.eq.’, ‘.ne.’, ‘.lt.’, ‘.le.’, etc.; use the Fortran 90 versions instead, i.e., ‘==’, ‘/=’, ‘