TABLE OF CONTENTS
INTRODUCTION
&INPUTHP
prefix  outdir  iverbosity  max_seconds  nq1  nq2  nq3  skip_equivalence_q  determine_num_pert_only  find_atpert  docc_thr  skip_type  equiv_type  perturb_only_atom  start_q  last_q  sum_pertq  compute_hp  conv_thr_chi  thresh_init  ethr_nscf  niter_max  alpha_mix(i)  nmix  num_neigh  lmin  rmax  dist_thr
INTRODUCTION
Input data format: { } = optional, [ ] = it depends, # = comment
Structure of the input data:
===============================================================================
&INPUTHP
...
/
Namelist: &INPUTHP

prefix 
CHARACTER 
Default: 
'pwscf'

Prepended to input/output filenames; must be the same
used in the calculation of unperturbed system.

outdir 
CHARACTER 
Default: 
value of the ESPRESSO_TMPDIR environment variable if set;
current directory ('./') otherwise

Directory containing input, output, and scratch files;
must be the same as specified in the calculation of
the unperturbed system.

iverbosity 
INTEGER 
Default: 
1

= 1 : minimal output
= 2 : as above + symmetry matrices, final response
matrices chi0 and chi1 and their inverse matrices,
full U matrix
= 3 : as above + various detailed info about the NSCF
calculation at k and k+q
= 4 : as above + response occupation matrices at every
iteration and for every q point in the star

max_seconds 
REAL 
Default: 
1.d7

Maximum allowed run time before the job stops smoothly.

nq1, nq2, nq3 
INTEGER 
Default: 
1,1,1

Parameters of the MonkhorstPack grid (no offset).
Same meaning as for nk1, nk2, nk3 in the input of pw.x.

skip_equivalence_q 
LOGICAL 
Default: 
.false.

If .true. then the HP code will skip the equivalence
analysis of q points, and thus the full grid of q points
will be used. Otherwise the symmetry is used to determine
equivalent q points (star of q), and then perform
calculations only for inequivalent q points.

determine_num_pert_only 
LOGICAL 
Default: 
.false.

See: 
find_atpert 
If .true. determines the number of perturbations
(i.e. which atoms will be perturbed) and exits smoothly
without performing any calculation. For DFT+U+V, it also
determines the indices of intersite couples.

find_atpert 
INTEGER 
Default: 
1

Method for searching of atoms which must be perturbed.
1 = Find how many inequivalent Hubbard atoms there are
by analyzing unperturbed occupations.
2 = Find how many Hubbard atoms to perturb based on
how many different Hubbard atomic types there are.
Warning: atoms which have the same type but which
are inequivalent by symmetry or which have different
occupations will not be distinguished in this case
(use option 1 or 3 instead).
3 = Find how many inequivalent Hubbard atoms
there are using symmetry. Atoms which have the
same type but are not equivalent by symmetry will
be distinguished in this case.

docc_thr 
REAL 
Default: 
5.D5

Threshold for a comparison of unperturbed occupations
which is needed for the selection of atoms which must
be perturbed. Can be used only when find_atpert = 1.

skip_type(i), i=1,ntyp 
LOGICAL 
Default: 
skip_type(i) = .false.

See: 
equiv_type 
skip_type(i), where i runs over types of atoms.
If skip_type(i)=.true. then no linearresponse
calculation will be performed for the ith atomic type:
in this case equiv_type(i) must be specified, otherwise
the HP code will stop. This option is useful if the
system has atoms of the same type but opposite spin
pollarizations (antiferromagnetic case).
This keyword cannot be used when find_atpert = 1.

equiv_type(i), i=1,ntyp 
INTEGER 
Default: 
equiv_type(i) = 0

See: 
skip_type 
equiv_type(i), where i runs over types of atoms.
equiv_type(i)=j, will make type i equivalent to type j
(useful when nspin=2). Such a merging of types is done
only at the postprocessing stage.
This keyword cannot be used when find_atpert = 1.

perturb_only_atom(i), i=1,ntyp 
LOGICAL 
Default: 
perturb_only_atom(i) = .false.

See: 
compute_hp 
If perturb_only_atom(i)=.true. then only the ith
atom will be perturbed and considered in the run.
This variable is useful when one wants to split
the whole calculation on parts.
Note: this variable has a higher priority than skip_type.

start_q 
INTEGER 
Default: 
1

See: 
last_q, sum_pertq

Computes only the q points from start_q to last_q.
IMPORTANT: start_q must be smaller or equal to
the total number of q points found.

last_q 
INTEGER 
Default: 
number of q points

See: 
start_q, sum_pertq

Computes only the q points from start_q to last_q.
IMPORTANT: last_q must be smaller or equal to
the total number of q points found.

compute_hp 
LOGICAL 
Default: 
.false.

See: 
perturb_only_atom 
If it is set to .true. then the HP code will collect
pieces of the chi0 and chi matrices (which must have
been produced in previous runs) and then compute
Hubbard parameters. The HP code will look for files
tmp_dir/HP/prefix.chi.i.dat. Note that all files
prefix.chi.i.dat (where i runs over all perturbed
atoms) must be placed in one folder tmp_dir/HP/.
compute_hp=.true. must be used only when the
calculation was parallelized over perturbations.

conv_thr_chi 
REAL 
Default: 
1.D5

Convergence threshold for the response function chi,
which is defined as a trace of the response
occupation matrix.

thresh_init 
REAL 
Default: 
1.D14

Initial threshold for the solution of the linear
system (first iteration). Needed to converge the
bare (noninteracting) response function chi0.
The specified value will be multiplied by the
number of electrons in the system.

ethr_nscf 
REAL 
Default: 
1.D11

Threshold for the convergence of eigenvalues during
the iterative diagonalization of the Hamiltonian in
the nonselfconsistentfield (NSCF) calculation at
k and k+q points. Note, this quantity is NOT extensive.

niter_max 
INTEGER 
Default: 
100

Maximum number of iterations in the iterative
solution of the linearresponse KohnSham equations.

alpha_mix(i) 
REAL 
Default: 
alpha_mix(1)=0.3

Mixing parameter (for the ith iteration) for updating
the response SCF potential using the modified Broyden
method. See: D.D. Johnson, PRB 38, 12807 (1988).

nmix 
INTEGER 
Default: 
4

Number of iterations used in potential mixing
using the modified Broyden method. See:
D.D. Johnson, PRB 38, 12807 (1988).

num_neigh 
INTEGER 
Default: 
6

Number of nearest neighbors of every Hubbard atom which
will be considered when writting Hubbard V parameters to
the file parameters.out, which can be used in the
subsequent DFT+U+V calculation. This keyword is used only
when lda_plus_u_kind = 2 (postprocessing stage).

lmin 
INTEGER 
Default: 
2

Minimum value of the orbital quantum number of the Hubbard
atoms starting from which (and up to the maximum l in the
system) Hubbard V will be written to the file parameters.out.
lmin refers to the orbital quantum number of the atom
corresponding to the first siteindex in Hubbard_V(:,:,:).
This keyword is used only when lda_plus_u_kind = 2 and only
in the postprocessing stage. Example: lmin=1 corresponds to
writing to file V between e.g. oxygen (with p states) and its
neighbors, and including V between transition metals (with d
states) and their neighbors. Instead, when lmin=2 only the
latter will be written to parameters.out.

rmax 
REAL 
Default: 
100.D0

Maximum distance (in Bohr) between two atoms to search
neighbors (used only at the postprocessing step when
lda_plus_u_kind = 2). This keyword is useful when there
are e.g. defects in the system.

dist_thr 
REAL 
Default: 
6.D4

Threshold (in Bohr) for comparing interatomic distances
when reconstructing the missing elements of the response
susceptibility in the postprocessing step.



