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input_cp2k_kpoints.F
Go to the documentation of this file.
1!--------------------------------------------------------------------------------------------------!
2! CP2K: A general program to perform molecular dynamics simulations !
3! Copyright 2000-2026 CP2K developers group <https://cp2k.org> !
4! !
5! SPDX-License-Identifier: GPL-2.0-or-later !
6!--------------------------------------------------------------------------------------------------!
7
8! **************************************************************************************************
9!> \brief function that build the kpoints section of the input
10!> \par History
11!> init [07.2014]
12!> \author JGH
13! **************************************************************************************************
15 USE bibliography, ONLY: macdonald1978,&
23 USE input_val_types, ONLY: char_t,&
24 enum_t,&
25 real_t
26 USE kinds, ONLY: default_path_length,&
27 dp
28 USE string_utilities, ONLY: newline,&
29 s2a
30#include "./base/base_uses.f90"
31
32 IMPLICIT NONE
33 PRIVATE
34
35 CHARACTER(len=*), PARAMETER, PRIVATE :: moduleN = 'input_cp2k_kpoints'
36
37 INTEGER, PARAMETER :: use_real_wfn = 101, &
38 use_complex_wfn = 100, &
43
49
50CONTAINS
51
52! **************************************************************************************************
53!> \brief Creates the Kpoints section
54!> SECTION: &kpoint... &end
55!> SCHEME [None, Gamma, Monkhorst-Pack, MacDonald, General]
56!> { nx ny nz }
57!> { nx ny nz sx sy sz }
58!> KPOINT x1 y1 z1 w1
59!> SYMMETRY [on, off]
60!> WAVEFUNCTION [real, complex]
61!> FULL_GRID [on, off]
62!> INVERSION_SYMMETRY_ONLY [on, off]
63!> SYMMETRY_BACKEND [K290, SPGLIB]
64!> SYMMETRY_REDUCTION_METHOD [K290, SPGLIB]
65!> VERBOSE [on, off]
66!> EPS_SYMMETRY value
67!> PARALLEL_GROUP_SIZE [-1,0,n]
68!>
69!> \param section the section to create
70!> \author JGH
71! **************************************************************************************************
72 SUBROUTINE create_kpoints_section(section)
73 TYPE(section_type), POINTER :: section
74
75 TYPE(keyword_type), POINTER :: keyword
76
77 cpassert(.NOT. ASSOCIATED(section))
78 CALL section_create(section, __location__, name="KPOINTS", &
79 description="Controls Brillouin-zone sampling with k-points.", &
80 n_keywords=1, n_subsections=0, repeats=.false.)
81
82 NULLIFY (keyword)
83 CALL keyword_create(keyword, __location__, name="SCHEME", &
84 description="K-point generation scheme. Available options are:"//newline// &
85 "- `NONE`"//newline// &
86 "- `GAMMA`"//newline// &
87 "- `MONKHORST-PACK`"//newline// &
88 "- `MACDONALD`"//newline// &
89 "- `GENERAL`"//newline// &
90 newline// &
91 "For `MONKHORST-PACK` the number of k points in all 3 dimensions has to"// &
92 " be supplied along with the keyword. For `MACDONALD` also the list of shifts."// &
93 " E.g. `MONKHORST-PACK 12 12 8`, `MACDONALD 4 4 4 0.25 0.25 0.25`."// &
94 " `GENERAL` uses the explicitly listed k-points as supplied and does not apply"// &
95 " SYMMETRY_BACKEND or SYMMETRY_REDUCTION_METHOD.", &
96 usage="SCHEME {KPMETHOD} {integer} {integer} ..", &
97 citations=[monkhorst1976, macdonald1978], &
98 n_var=-1, type_of_var=char_t)
99 CALL section_add_keyword(section, keyword)
100 CALL keyword_release(keyword)
101
102 CALL keyword_create(keyword, __location__, name="KPOINT", &
103 description="Specify kpoint coordinates and weight. ", &
104 usage="KPOINT x y z w", repeats=.true., &
105 n_var=4, type_of_var=real_t)
106 CALL section_add_keyword(section, keyword)
107 CALL keyword_release(keyword)
108
109 CALL keyword_create(keyword, __location__, name="UNITS", &
110 description="Special k-points are defined either in units"// &
111 " of reciprocal lattice vectors or in Cartesian coordinates in units of 2Pi/len."// &
112 " B_VECTOR: in multiples of the reciprocal lattice vectors (b)."// &
113 " CART_ANGSTROM: In units of 2*Pi/Angstrom."// &
114 " CART_BOHR: In units of 2*Pi/Bohr.", &
115 usage="UNITS <value>", type_of_var=char_t, default_c_val="B_VECTOR")
116 CALL section_add_keyword(section, keyword)
117 CALL keyword_release(keyword)
118
119 CALL keyword_create(keyword, __location__, name="SYMMETRY", &
120 description="Use symmetry to reduce the number of kpoints.", &
121 usage="SYMMETRY <LOGICAL>", &
122 default_l_val=.false., lone_keyword_l_val=.true.)
123 CALL section_add_keyword(section, keyword)
124 CALL keyword_release(keyword)
125
126 CALL keyword_create(keyword, __location__, name="FULL_GRID", &
127 description="Use the full, non-symmetry-reduced k-point grid.", &
128 usage="FULL_GRID <LOGICAL>", &
129 default_l_val=.false., lone_keyword_l_val=.true.)
130 CALL section_add_keyword(section, keyword)
131 CALL keyword_release(keyword)
132
133 CALL keyword_create(keyword, __location__, name="INVERSION_SYMMETRY_ONLY", &
134 description="Restrict k-point reduction to k-space inversion "// &
135 "(time-reversal) symmetry.", &
136 usage="INVERSION_SYMMETRY_ONLY <LOGICAL>", &
137 default_l_val=.false., lone_keyword_l_val=.true.)
138 CALL section_add_keyword(section, keyword)
139 CALL keyword_release(keyword)
140
141 CALL keyword_create(keyword, __location__, name="SYMMETRY_BACKEND", &
142 description="Select the backend used to provide and apply atomic "// &
143 "k-point symmetry operations. K290 is the established default. "// &
144 "SPGLIB uses the symmetry operations returned by SPGLIB, including "// &
145 "their fractional translations. This applies to Monkhorst-Pack and MacDonald "// &
146 "meshes. For GENERAL, the explicit k-point list is used as supplied. If "// &
147 "SYMMETRY_REDUCTION_METHOD is not specified, it follows the selected backend.", &
148 usage="SYMMETRY_BACKEND K290", type_of_var=enum_t, &
149 enum_c_vals=s2a("K290", "SPGLIB"), &
151 enum_desc=s2a("Use the existing K290 k-point symmetry backend.", &
152 "Use SPGLIB symmetry operations as k-point symmetry backend."), &
153 default_i_val=use_k290_kpoint_backend)
154 CALL section_add_keyword(section, keyword)
155 CALL keyword_release(keyword)
156
157 CALL keyword_create(keyword, __location__, name="SYMMETRY_REDUCTION_METHOD", &
158 description="Select the method used to reduce Monkhorst-Pack and MacDonald "// &
159 "k-point meshes when atomic symmetry is enabled. K290 is the established "// &
160 "default. SPGLIB uses the symmetry operations returned by SPGLIB for the "// &
161 "k-point reduction. GENERAL k-point lists are not reduced. With "// &
162 "SYMMETRY_BACKEND K290 this can be used as a comparison mode using K290 "// &
163 "operations for SPGLIB-generated mappings.", &
164 usage="SYMMETRY_REDUCTION_METHOD K290", type_of_var=enum_t, &
165 enum_c_vals=s2a("K290", "SPGLIB"), &
167 enum_desc=s2a("Use the existing K290 k-point symmetry reduction method.", &
168 "Use SPGLIB symmetry operations for k-point reduction."), &
169 default_i_val=use_k290_kpoint_symmetry)
170 CALL section_add_keyword(section, keyword)
171 CALL keyword_release(keyword)
172
173 CALL keyword_create(keyword, __location__, name="VERBOSE", &
174 description="Verbose output information.", &
175 usage="VERBOSE <LOGICAL>", &
176 default_l_val=.false., lone_keyword_l_val=.true.)
177 CALL section_add_keyword(section, keyword)
178 CALL keyword_release(keyword)
179
180 CALL keyword_create(keyword, __location__, name="EPS_SYMMETRY", variants=["EPS_GEO"], &
181 description="Accuracy in k-point symmetry determination."//newline// &
182 "EPS_GEO is accepted as an alias.", &
183 usage="EPS_SYMMETRY <real>", &
184 default_r_val=1.0e-6_dp)
185 CALL section_add_keyword(section, keyword)
186 CALL keyword_release(keyword)
187
188 CALL keyword_create(keyword, __location__, name="PARALLEL_GROUP_SIZE", &
189 description="Number of MPI processes to be used for a single k-point."// &
190 " This number must divide the total number of processes."// &
191 " The number of groups must divide the total number of kpoints."// &
192 " Value=-1 (smallest possible number of processes per group, satisfying the constraints)."// &
193 " Value=0 (all processes)."// &
194 " Value=n (exactly n processes).", &
195 usage="PARALLEL_GROUP_SIZE <integer>", &
196 default_i_val=-1)
197 CALL section_add_keyword(section, keyword)
198 CALL keyword_release(keyword)
199
200 CALL keyword_create(keyword, __location__, name="WAVEFUNCTIONS", &
201 description="Select whether real or complex wavefunctions should be used "// &
202 "when allowed by the k-point set. REAL wavefunctions can only represent "// &
203 "Gamma or special k-points and symmetry operations with real Bloch phases. "// &
204 "Use COMPLEX for general atomic k-point symmetries with nontrivial phases.", &
205 usage="WAVEFUNCTIONS REAL", &
206 default_i_val=use_complex_wfn, &
207 enum_c_vals=s2a("REAL", "COMPLEX"), &
208 enum_desc=s2a("Use real wavefunctions (if possible by kpoints specified).", &
209 "Use complex wavefunctions (default)."), &
210 enum_i_vals=[use_real_wfn, use_complex_wfn])
211 CALL section_add_keyword(section, keyword)
212 CALL keyword_release(keyword)
213
214 END SUBROUTINE create_kpoints_section
215
216! **************************************************************************************************
217!> \brief ...
218!> \param section ...
219!> \param section_name ...
220!> \author JGH
221! **************************************************************************************************
222 SUBROUTINE create_kpoint_set_section(section, section_name)
223 TYPE(section_type), POINTER :: section
224 CHARACTER(LEN=*), OPTIONAL :: section_name
225
226 CHARACTER(len=default_path_length) :: my_section_name
227 TYPE(keyword_type), POINTER :: keyword
228
229 IF (PRESENT(section_name)) THEN
230 my_section_name = section_name
231 ELSE
232 my_section_name = "KPOINT_SET"
233 END IF
234
235 cpassert(.NOT. ASSOCIATED(section))
236 CALL section_create(section, __location__, name=my_section_name, &
237 description="Specifies a k-point line to be calculated.", &
238 n_keywords=0, n_subsections=0, repeats=.true.)
239 ! keywords
240 NULLIFY (keyword)
241 CALL keyword_create(keyword, __location__, name="SPECIAL_POINT", &
242 description="Name and coordinates of a special k-point", &
243 usage="SPECIAL_POINT GAMMA 0.0 0.0 0.0", n_var=-1, type_of_var=char_t, repeats=.true.)
244 CALL section_add_keyword(section, keyword)
245 CALL keyword_release(keyword)
246 !
247 CALL keyword_create(keyword, __location__, name="NPOINTS", &
248 description="Number of k-points along the line.", &
249 default_i_val=0)
250 CALL section_add_keyword(section, keyword)
251 CALL keyword_release(keyword)
252 !
253 CALL keyword_create(keyword, __location__, name="UNITS", &
254 description="Special k-points are defined either in units"// &
255 " of reciprocal lattice vectors or in Cartesian coordinates in units of 2Pi/len."// &
256 " B_VECTOR: in multiples of the reciprocal lattice vectors (b)."// &
257 " CART_ANGSTROM: In units of 2*Pi/Angstrom."// &
258 " CART_BOHR: In units of 2*Pi/Bohr.", &
259 usage="UNITS <value>", type_of_var=char_t, default_c_val="B_VECTOR")
260 CALL section_add_keyword(section, keyword)
261 CALL keyword_release(keyword)
262
263 END SUBROUTINE create_kpoint_set_section
264
265END MODULE input_cp2k_kpoints
collects all references to literature in CP2K as new algorithms / method are included from literature...
integer, save, public monkhorst1976
integer, save, public macdonald1978
function that build the kpoints section of the input
integer, parameter, public use_spglib_kpoint_symmetry
integer, parameter, public use_k290_kpoint_symmetry
subroutine, public create_kpoints_section(section)
Creates the Kpoints section SECTION: &kpoint... &end SCHEME [None, Gamma, Monkhorst-Pack,...
integer, parameter, public use_real_wfn
subroutine, public create_kpoint_set_section(section, section_name)
...
integer, parameter, public use_spglib_kpoint_backend
integer, parameter, public use_k290_kpoint_backend
integer, parameter, public use_complex_wfn
represents keywords in an input
subroutine, public keyword_release(keyword)
releases the given keyword (see doc/ReferenceCounting.html)
subroutine, public keyword_create(keyword, location, name, description, usage, type_of_var, n_var, repeats, variants, default_val, default_l_val, default_r_val, default_lc_val, default_c_val, default_i_val, default_l_vals, default_r_vals, default_c_vals, default_i_vals, lone_keyword_val, lone_keyword_l_val, lone_keyword_r_val, lone_keyword_c_val, lone_keyword_i_val, lone_keyword_l_vals, lone_keyword_r_vals, lone_keyword_c_vals, lone_keyword_i_vals, enum_c_vals, enum_i_vals, enum, enum_strict, enum_desc, unit_str, citations, deprecation_notice, removed)
creates a keyword object
objects that represent the structure of input sections and the data contained in an input section
subroutine, public section_create(section, location, name, description, n_keywords, n_subsections, repeats, citations, deprecation_notice)
creates a list of keywords
subroutine, public section_add_keyword(section, keyword)
adds a keyword to the given section
a wrapper for basic fortran types.
integer, parameter, public real_t
integer, parameter, public char_t
integer, parameter, public enum_t
Defines the basic variable types.
Definition kinds.F:23
integer, parameter, public dp
Definition kinds.F:34
integer, parameter, public default_path_length
Definition kinds.F:58
Utilities for string manipulations.
character(len=1), parameter, public newline
represent a keyword in the input
represent a section of the input file