Source code for psyclone.domain.lfric.lfric_cell_iterators

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# Authors R. W. Ford, A. R. Porter and S. Siso, STFC Daresbury Lab
# Modified I. Kavcic, A. Coughtrie, L. Turner and O. Brunt, Met Office
# Modified J. Henrichs, Bureau of Meteorology
# Modified A. B. G. Chalk and N. Nobre, STFC Daresbury Lab

''' This module implements the LFRicCellIterators collection which handles
    the requirements of kernels that operator on cells.'''

from psyclone.domain.lfric.lfric_collection import LFRicCollection
from psyclone.domain.lfric.lfric_kern import LFRicKern
from psyclone.domain.lfric.lfric_types import LFRicTypes
from psyclone.errors import GenerationError
from psyclone.psyir.nodes import Assignment, Reference
from psyclone.psyir.symbols import ArgumentInterface




class LFRicCellIterators(LFRicCollection):
    '''
    Handles all entities required by kernels that operate on cell-columns.

    :param kern_or_invoke: the Kernel or Invoke for which to manage cell
                           iterators.
    :type kern_or_invoke: :py:class:`psyclone.domain.lfric.LFRicKern` |
                          :py:class:`psyclone.lfric.LFRicInvoke`

    :raises GenerationError: if an Invoke has no field or operator arguments.

    '''
    def __init__(self, kern_or_invoke):
        super().__init__(kern_or_invoke)

        # Dictionary to hold the names of the various nlayers variables and
        # (for invokes) the kernel argument to which each corresponds.
        self._nlayers_names = {}

        if self._invoke:
            # Each kernel that operates on either the domain or cell-columns
            # needs an 'nlayers' obtained from the first field/operator
            # argument.
            for kern in self._invoke.schedule.walk(LFRicKern):
                if kern.iterates_over != "dof":
                    arg = kern.arguments.first_field_or_operator
                    sym = self.symtab.find_or_create_tag(
                        f"nlayers_{arg.name}",
                        symbol_type=LFRicTypes("MeshHeightDataSymbol"))
                    self._nlayers_names[sym.name] = arg

            first_var = None
            for var in self._invoke.psy_unique_vars:
                if not var.is_scalar:
                    first_var = var
                    break
            if not first_var:
                raise GenerationError(
                    "Cannot create an Invoke with no field/operator "
                    "arguments.")
            self._first_var = first_var



    def stub_declarations(self):
        '''
        Declare entities required for a kernel stub that operates on
        cell-columns.

        '''
        super().stub_declarations()
        if self._kernel.cma_operation not in ["apply", "matrix-matrix"]:
            nlayers = self.symtab.find_or_create_tag(
                "nlayers",
                symbol_type=LFRicTypes("MeshHeightDataSymbol")
            )
            nlayers.interface = ArgumentInterface(
                                        ArgumentInterface.Access.READ)
            self.symtab.append_argument(nlayers)




    def initialise(self, cursor):
        '''
        Look-up the number of vertical layers in the mesh in the PSy layer.

        :param int cursor: position where to add the next initialisation
            statements.

        :returns: Updated cursor value.
        :rtype: int

        '''
        if not self._nlayers_names or not self._invoke:
            return cursor

        # Sort for test reproducibility
        sorted_names = list(self._nlayers_names.keys())
        sorted_names.sort()
        init_cursor = cursor
        for name in sorted_names:
            symbol = self.symtab.lookup(name)
            var = self._nlayers_names[name]
            stmt = Assignment.create(
                    lhs=Reference(symbol),
                    rhs=var.generate_method_call("get_nlayers"))
            if cursor == init_cursor:
                stmt.preceding_comment = "Initialise number of layers"
            self._invoke.schedule.addchild(stmt, cursor)
            cursor += 1
        return cursor