MOLPRO

6 PROGRAM CONTROL 33
6.6.1 Examples for do loops
The first example shows how to compute a potential energy surface for water.
***,H2O potential
symmetry,x
!use cs symmetry
geometry={
o; !z-matrix
h1,o,r1(i);
h2,o,r2(i),h1,theta(i) }
basis=vdz
!define basis set
angles=[100,104,110]
!list of angles
distances=[1.6,1.7,1.8,1.9,2.0] !list of distances
i=0 !initialize a counter
do ith=1,#angles
!loop over all angles H1-O-H2
do ir1=1,#distances
!loop over distances for O-H1
do ir2=1,ir1
!loop over O-H2 distances(r1.ge.r2)
i=i+1
!increment counter
r1(i)=distances(ir1)
!save r1 for this geometry
r2(i)=distances(ir2)
!save r2 for this geometry
theta(i)=angles(ith)
!save theta for this geometry
hf;
!do SCF calculation
escf(i)=energy
!save scf energy for this geometry
ccsd(t);
!do CCSD(T) calculation
eccsd(i)=energc
!save CCSD energy
eccsdt(i)=energy
!save CCSD(T) energy
enddo
!end of do loop ith
enddo
!end of do loop ir1
enddo
!end of do loop ir2
{table,r1,r2,theta,escf,eccsd,eccsdt !produce a table with results
head, r1,r2,theta,scf,ccsd,ccsd(t) !modify column headers for table
save,h2o.tab
!save the table in file h2o.tab
title,Results for H2O, basis $basis !title for table
sort,3,1,2}
!sort table
http://www.molpro.net/info/current/examples/h2o_pes_ccsdt.com
The next example shows how to loop over many methods.
***,h2o benchmark
$method=[hf,fci,ci,cepa(0),cepa(1),cepa(2),cepa(3),mp2,mp3,mp4,\
qci,ccsd,bccd,qci(t),ccsd(t),bccd(t),casscf,mrci,acpf]
basis=dz
!Double zeta basis set
geometry={o;h1,o,r;h2,o,r,h1,theta} !Z-matrix for geometry
r=1 ang, theta=104 !Geometry parameters
do i=1,#method
!Loop over all requested methods
$method(i);
!call program
e(i)=energy
!save energy for this method
enddo
escf=e(1)
!scf energy
efci=e(2)
!fci energy
table,method,e,e-escf,e-efci
!print a table with results
!Title for table:
title,Results for H2O, basis $basis, R=$r Ang, Theta=$theta degree
http://www.molpro.net/info/current/examples/h2o_manymethods.com
6.7 Branching (IF/ELSEIF/ENDIF)
IF blocks and IF/ELSEIF blocks can be constructed as in FORTRAN.