structural optimisation
Posted: Sat Jan 27, 2018 10:49 am
Hi abinit user,
I am working on structural optimization . but every time I am getting boxcut error. even though I am reducing ecut is not working for me. Please help. here is the content of input file.
#Define the methodology to find the minimum
ionmov 2 # Use the modified Broyden algorithm
ntime 150 # Maximum number of Broyden "timesteps"
tolmxf 5.0d-4 # Stopping criterion for the geometry optimization : when
# the residual forces are less than tolmxf, the Broyden
# algorithm can stop
toldff 5.0d-5 # Will stop the SCF cycle when, twice in a row,
optcell 2
#Definition of the unit cell
acell 12.237 8.255 8.508 angstrom
#rprim 1 0 0 0 1 0 0 0 1 # This line, defining orthogonal primitive vectors,
# is commented, because it is precisely the default value of rprim
#Definition of the atom types
#Definition of the atoms
natom 78
#Definition of the k-point grid
kptopt 1 # Enter the k points manually
ngkpt 2 4 4 # Only one k point is needed for isolated system,
# taken by default to be 0.0 0.0 0.0
shiftk 0.5 0.5 0.5
#Definition of the SCF procedure
nstep 100 # Maximal number of SCF cycles
#toldfe 1.0d-6 # Will stop when, twice in a row, the difference
# between two consecutive evaluations of total energy
# differ by less than toldfe (in Hartree)
# This value is way too large for most realistic studies of materials
diemac 2.0 # Although this is not mandatory, it is worth to
# precondition the SCF cycle. The model dielectric
# function used as the standard preconditioner
# is described in the "dielng" input variable section.
dilatmx 0.925
# Here, we follow the prescriptions for molecules
# in a big box
#Definition of the planewave basis set
ecut 500 eV
ecutsm 1 Hartree
# add to conserve old < 6.7.2 behavior for calculating forces at each SCF step
optforces 1
and here is the error which I am getting:
ERROR
src_file: getcut.F90
src_line: 157
mpi_rank: 0
message: |
Choice of acell, ngfft, and ecut
===> basis sphere extends BEYOND fft box !
Recall that boxcut=Gcut(box)/Gcut(sphere) must be > 1.
Action : try larger ngfft or smaller ecut.
Note that ecut=effcut/boxcut**2 and effcut= 0.517851
I am working on structural optimization . but every time I am getting boxcut error. even though I am reducing ecut is not working for me. Please help. here is the content of input file.
#Define the methodology to find the minimum
ionmov 2 # Use the modified Broyden algorithm
ntime 150 # Maximum number of Broyden "timesteps"
tolmxf 5.0d-4 # Stopping criterion for the geometry optimization : when
# the residual forces are less than tolmxf, the Broyden
# algorithm can stop
toldff 5.0d-5 # Will stop the SCF cycle when, twice in a row,
optcell 2
#Definition of the unit cell
acell 12.237 8.255 8.508 angstrom
#rprim 1 0 0 0 1 0 0 0 1 # This line, defining orthogonal primitive vectors,
# is commented, because it is precisely the default value of rprim
#Definition of the atom types
#Definition of the atoms
natom 78
#Definition of the k-point grid
kptopt 1 # Enter the k points manually
ngkpt 2 4 4 # Only one k point is needed for isolated system,
# taken by default to be 0.0 0.0 0.0
shiftk 0.5 0.5 0.5
#Definition of the SCF procedure
nstep 100 # Maximal number of SCF cycles
#toldfe 1.0d-6 # Will stop when, twice in a row, the difference
# between two consecutive evaluations of total energy
# differ by less than toldfe (in Hartree)
# This value is way too large for most realistic studies of materials
diemac 2.0 # Although this is not mandatory, it is worth to
# precondition the SCF cycle. The model dielectric
# function used as the standard preconditioner
# is described in the "dielng" input variable section.
dilatmx 0.925
# Here, we follow the prescriptions for molecules
# in a big box
#Definition of the planewave basis set
ecut 500 eV
ecutsm 1 Hartree
# add to conserve old < 6.7.2 behavior for calculating forces at each SCF step
optforces 1
and here is the error which I am getting:
ERROR
src_file: getcut.F90
src_line: 157
mpi_rank: 0
message: |
Choice of acell, ngfft, and ecut
===> basis sphere extends BEYOND fft box !
Recall that boxcut=Gcut(box)/Gcut(sphere) must be > 1.
Action : try larger ngfft or smaller ecut.
Note that ecut=effcut/boxcut**2 and effcut= 0.517851