# Hydrogen diatomic molecule - comparative study
# of geometry optimizations with ionmov=2 or 3
ndtset 12 udtset 6 2
xcart:? -0.60 0 0 0.60 0 0
xcart+? -0.10 0 0 0.10 0 0
ionmov?1 2
ionmov?2 3
getwfk -1
acell 9 6 6
diemac 1.0d0
diemix 0.333333333333d0
ecut 4
enunit 2
intxc 1
ionmov 2
kptopt 0
kpt 3*0
natom 2 nband 1
nkpt 1
nstep 20
nsym 1
ntime 8
ntime61 2 # The Broyden algorithm leads to a divergence
# for larger ntime, specifically for dataset 61
# The ionmov=3 algorithm behaves perfectly, though.
ntypat 1
occopt 1
rprim 1 0 0 0 1 0 0 0 1
tolmxf 5.0d-4
toldff 1.0d-9 # Such an accuracy is not needed in production runs.
# However, for test portability, it was to be used here
typat 2*1
wtk 1
znucl 1.0
#%%
#%% [setup]
#%% executable = abinit
#%% [files]
#%% files_to_test =
#%% t48.out, tolnlines = 0, tolabs = 5.303e-10, tolrel = 8.000e-03, fld_options = -easy
#%% psp_files = 1h.pspnc
#%% [paral_info]
#%% max_nprocs = 1
#%% [extra_info]
#%% keywords =
#%% authors = Unknown
#%% description =
#%% H2 molecule in a big box.
#%% Comparison of the modified Broyden algorithm (ionmov=3) with the
#%% original one (ionmov=2). Start with different values
#%% of xcart, from 0.6 to 1.1, by step of 0.1 . The number of Broyden
#%% steps needed to reach acceptable residual forces
#%% with the ionmov=3 algorithm are : 3, 2, 2, 3, 3, 4, while
#%% with the ionmov=2 algorithms, one get : 4, 3, 2, 5, and then,
#%% either the algorithm does not converge within 8 steps, or it
#%% converges to a saddle point of the energy !
#%% This test was hard to make portable. This is why the tolerance
#%% for fldiff is very large.
#%% topics = GeoOpt
#%%