This file was started on April 14, 2021

How to build GAMESS version 30 September 2020 (R2)
with CHARMM c45b2 (also free version & c46a2)

The content of the file at

http://ala.cmm.ki.si/gamess/20200930.2/gamess-20200930.2-charmm.tar.gz

is as follows:

gamess/Compile-CHARMM-with-GAMESS.txt   (current instructions)
gamess/charmm/                          (optional, see #3 below!)
gamess/gamess-20200930.2_charmm.patch   (patch for gamess-20200930.2
                                         to work with c45b2 charmm versions)


This is an example for 64 bit gnu platforms (gfortran) in parallel, but
it may be adapted for other environments too by modifying tool/gmscomp
file (see GAMESS installation instructions)
cmake recognizes also the intel compiler...

----------------------------------------------------------------------

Assuming your charmm tree is here: ~/charmm/c45b2


1. copy all gamess/source files from GAMESS distribution to CHARMM
   source tree (mkdir ~/charmm/c45b2/source/gamint/gamess first):
   cp -av ~/gamess-orig/gamess/source/* ~/charmm/c45b2/source/gamint/gamess

2. patch the gamess-sources

   Download:

   http://ala.cmm.ki.si/gamess/20200930.2/gamess-20200930.2-charmm.tar.gz

   unpack this .tar.gz file into ~/charmm/c45b2/gamess

   cd  ~/charmm/c45b2

   patch -p1 < gamess/gamess-20200930.2_charmm.patch

3. Only in the case you have c44b1 or above but not c45b2/c46a2 do these
   additional commands (though they don't do any damage):

   cd ~/charmm/c45b2

   cp gamess/charmm/{gmscom,addomp.sh} tool
   cp gamess/charmm/{ddi.F90,CMakeLists.txt} source/gamint

   chmod 755 tool/gmscomp tool/addomp.sh

3a. SPECIAL NOTE for gfortran-10: In the case of gfortran-10.X one
    needs to copy gamess/charmm/gmscomp_gcc10 to tool/gmscomp !

4. Compile

   mkdir ~/charmm/build
   cd ~/charmm/build
   ../c45b2/configure --gamess
   make ; make ; make

   It compiles for about 15 minutes. To speedup it is possible to use
   the following:

   time (make -j 8 ; make -j 8)

   It is difficult to impose the order of compilation in cmake. The
   easiest way out of this problem is to specify make two or more
   times since the compilation order is a random process. Until you
   get the executable.

5. The above should produce a working executable which you may want
   to test and get the following result:
   ABNR>       10-116448.48250     13.05082      4.58542      0.01550

   cd ~charmm/c45b2/test ; mkdir -p scratch ; rm -f scratch/{test.dat,ala.gms}
   ~/charmm/build/charmm -i cquantumtest/gmstst.inp|grep 'ABNR>'|tail -1