# 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

 pp_dirpath "$ABI_PSPDIR"
 pseudos "PseudosTM_pwteter/1h.pspnc"

#%%<BEGIN TEST_INFO>
#%% [setup]
#%% executable = abinit
#%% [files]
#%% files_to_test = 
#%%  t48.out, tolnlines = 0, tolabs = 5.303e-10, tolrel = 8.000e-03, fld_options = -easy
#%% [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
#%%<END TEST_INFO>