Caffeinate

pymatgen/io/espresso/caffeinate.py

@@ -0,0 +1,168 @@
+"""
+Classes for converting VASP inputs to PWSCF inputs.
+
+Supported VASP inputs:
+    KPOINTS*
+    POSCAR
+Not (yet) supported:
+    INCAR
+    KPOINTS: generalized regular grids or
+             fully automatic (KSPACING) grids
+"""
+
+# TODO: imports need linting!
+# TODO: Gamma vs. M-P conversion should be tested with an actual VASP/QE comp.
+
+from __future__ import annotations
+
+import contextlib
+import warnings
+
+import numpy as np
+
+from pymatgen.core.structure import Structure
+
+from pymatgen.io.vasp.inputs import Kpoints, Poscar
+from pymatgen.io.espresso.inputs import pwin
+
+# TODO
+# introduce class Caffeinator():
+    # TODO: define get_pwin method 
+    # which reads in a full set of VASP inputs 
+    # and returns a full pwin object
+
+# Functions for converting a specified VASP input file
+# to PWin format
+
+def caffeinate(vasp_in):
+    if isinstance(vasp_in, Kpoints):
+        return _caffeinate_kpoints(vasp_in)
+    elif isinstance(vasp_in, Poscar):
+        return _caffeinate_poscar(vasp_in)
+    else:
+        # TODO: Define a warning
+        return vasp_in
+
+def _caffeinate_kpoints(kpoints):
+    """
+    Convert a Kpoints object to a KPointsCard object.
+
+    NOTE: Cartesian coordinates are preserved in their original form, 
+    i.e. in units of 2*pi/a where a is defined in an accompanying Poscar object.
+    """
+    k_style = kpoints.style
+    k_num = kpoints.num_kpts
+    k_pts = kpoints.kpts
+    k_shift = kpoints.kpts_shift
+    k_wts = kpoints.kpts_weights
+    k_coord = kpoints.coord_type
+    k_lab = kpoints.labels
+
+    if k_style.name.lower()[0] in "gm":
+        if ( 
+            all(int(x) == 1 for x in k_pts[0]) and 
+            all(x == 0.0 for x in k_shift) 
+            ):
+            opt_str = "gamma"
+        else:
+            opt_str = "automatic"
+
+        # TODO: option assignment from string should be fixed in next version
+        option = pwin.KPointsCard.opts.from_string(opt_str)
+        grid = [ int(x) for x in k_pts[0] ]
+        shift = [ bool(x) for x in k_shift ]
+
+        # TODO: needs checking
+        # convert gamma-centered grids to Monkhorst-Pack grids, if necessary
+        # (i.e. for even subdivisions)
+        if k_style.name.lower()[0] == "g":
+            for i, x in enumerate(grid):
+                if not x % 2:
+                    shift[i] = not shift[i]
+
+        return pwin.KPointsCard(
+                option = option, 
+                grid = grid, 
+                shift = shift, 
+                k = [], 
+                weights = [], 
+                labels = [])
+
+    elif k_style.name.lower()[0] == "l":
+        if k_coord.lower()[0] == "r":
+            opt_str = "crystal_b"
+        else:
+            opt_str = "tpiba_b"
+
+        pw_k = [list(k_pts[0])]
+        pw_lbls = [k_lab[0]]
+        pw_wts = [k_num]
+        for i in range(1,len(k_lab)):
+            if k_lab[i] == k_lab[i - 1]:
+                pass
+            elif not i % 2:
+                pw_lbls.append(k_lab[i])
+                pw_wts[-1] = 1
+                pw_wts.append(k_num)
+                pw_k.append(list(k_pts[i]))
+            else:
+                pw_lbls.append(k_lab[i])
+                pw_wts.append(k_num)
+                pw_k.append(list(k_pts[i]))
+
+        pw_wts[-1] = 1
+        option = pwin.KPointsCard.opts.from_string(opt_str)
+
+        return pwin.KPointsCard(
+                option = option,
+                grid = [],
+                shift = [],
+                k = pw_k,
+                weights = pw_wts,
+                labels = pw_lbls)
+
+    elif k_style.name.lower()[0] in "rc" and k_num > 0:
+        if k_num == 1 and (
+                all(int(x) == 1 for x in k_pts[0]) and
+                all(x == 0.0 for x in k_shift)
+                ):
+            opt_str = "gamma"
+        elif k_style.name.lower()[0] == "c":
+            opt_str = "tpiba"
+        else:
+            opt_str = "crystal"
+
+        option = pwin.KPointsCard.opts.from_string(opt_str)
+        # TODO: finish parsing k-points 
+
+
+    else:
+        # In this case the style we have either a fully-automatic grid with a 
+        # defined spacing (officially deprecated by VASP) or a generalized 
+        # regular grid.
+        # Neither option has a direct PWSCF parallel and conversion has not
+        # been implemented yet.
+        # TODO: Define a warning 
+        return kpoints
+
+    if "tpiba" in option:
+        # TODO: Define a warning.
+        # Without an accompanying POSCAR, VASP's cartesian coordinates
+        # cannot properly be converted to PWSCF's tpiba coordinates.
+        # This warning can be ignored in pwin if a Poscar object is
+        # provided.
+        pass
+
+    # DEBUGGING (TODO)
+    return option
+
+# TODO:
+def _caffeinate_poscar(poscar):
+    """
+    Convert a Poscar object to the following three objects:
+        - AtomicPositionsCard
+        - AtomicSpeciesCard
+        - CellParametersCard
+    """
+    pass
+