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# Authors R. W. Ford, A. R. Porter, S. Siso and N. Nobre, STFC Daresbury Lab
# J. Henrichs, Bureau of Meteorology
# I. Kavcic, Met Office
'''This module contains the GOConstLoopBoundsTrans.'''
from psyclone.errors import InternalError
from psyclone.gocean1p0 import GOInvokeSchedule, GOLoop
from psyclone.psyGen import Transformation
from psyclone.psyir.frontend.fortran import FortranReader
from psyclone.psyir.nodes import Assignment, Reference, StructureReference
from psyclone.psyir.symbols import INTEGER_TYPE, DataSymbol, DataTypeSymbol
from psyclone.psyir.transformations import TransformationError
from psyclone.configuration import Config
[docs]class GOConstLoopBoundsTrans(Transformation):
''' Use of a common constant variable for each loop bound within
a GOInvokeSchedule. By deafault, PSyclone generates loops where
the bounds are obtained by de-referencing a field object, e.g.:
.. code-block:: fortran
DO j = my_field%grid%internal%ystart, my_field%grid%internal%ystop
Some compilers are able to produce more efficient code if they are
provided with information on the relative trip-counts of the loops
within an Invoke. With constant loop bounds, PSyclone generates code
like:
.. code-block:: fortran
ny = my_field%grid%subdomain%internal%ystop
...
DO j = 1, ny-1
In practice, the application of the constant loop bounds transformation
looks something like, e.g.:
>>> from psyclone.parse.algorithm import parse
>>> from psyclone.psyGen import PSyFactory
>>> import os
>>> TEST_API = "gocean1.0"
>>> _, info = parse(os.path.join("tests", "test_files", "gocean1p0",
... "single_invoke.f90"),
... api=TEST_API)
>>> psy = PSyFactory(TEST_API).create(info)
>>> invoke = psy.invokes.get('invoke_0_compute_cu')
>>> schedule = invoke.schedule
>>>
>>> from psyclone.transformations import GOConstLoopBoundsTrans
>>> clbtrans = GOConstLoopBoundsTrans()
>>>
>>> clbtrans.apply(schedule)
>>> print(schedule.view())
'''
def __str__(self):
return "Use constant loop bounds for all loops in a GOInvokeSchedule"
@property
def name(self):
'''
:returns: the name of the Transformation as a string.
:rtype: str
'''
return "GOConstLoopBoundsTrans"
[docs] def validate(self, node, options=None):
'''Checks if it is valid to apply the GOConstLoopBoundsTrans
transform.
:param node: the GOInvokeSchedule to transform.
:type node: :py:class:`psyclone.gocean1p0.GOInvokeSchedule`
:param options: a dictionary with options for transformations.
:type options: Optional[Dict[str, Any]]
:raises TransformationError: if the supplied node is not a \
GOInvokeSchedule.
:raises TransformationError: if the supplied schedule has loops with \
a loop with loop_type different than 'inner' or 'outer'.
:raises TransformationError: if the supplied schedule has loops with \
attributes for index_offsets, field_space, iteration_space and \
loop_type that don't appear in the GOLoop.bounds_lookup table.
:raises TransformationError: if the supplied schedule doesn't have a \
field argument.
'''
if not isinstance(node, GOInvokeSchedule):
raise TransformationError(
f"GOConstLoopBoundsTrans can only be applied to "
f"'GOInvokeSchedule' but found '{type(node).__name__}'.")
for loop in node.walk(GOLoop):
if loop.loop_type not in ["inner", "outer"]:
raise TransformationError(
f"GOConstLoopBoundsTrans can not transform a loop with "
f"loop_type '{loop.loop_type}', only 'inner' or 'outer' "
f"loop_type values are expected.")
if loop.index_offset not in loop.bounds_lookup:
raise TransformationError(
f"GOConstLoopBoundsTrans can not transform a loop with "
f"index_offset '{loop.index_offset}' because it is not in "
f"the bounds lookup table, the available index_offset "
f"values are {list(loop.bounds_lookup.keys())}.")
table = loop.bounds_lookup[loop.index_offset]
if loop.field_space not in table:
raise TransformationError(
f"GOConstLoopBoundsTrans can not transform a loop with "
f"field_space '{loop.field_space}' because it is not in "
f"the bounds lookup table, the available field_space "
f"values are {list(table.keys())}.")
table = table[loop.field_space]
if loop.iteration_space not in table:
raise TransformationError(
f"GOConstLoopBoundsTrans can not transform a loop with "
f"iteration_space '{loop.iteration_space}' because it is "
f"not in the bounds lookup table, the available "
f"iteration_space values are {list(table.keys())}.")
table = table[loop.iteration_space]
if loop.loop_type not in table:
raise TransformationError(
f"GOConstLoopBoundsTrans can not transform a loop with "
f"loop_type '{loop.loop_type}' because it is not in the "
f"bounds lookup table, the available loop_type values are "
f"{list(table.keys())}.")
# Make sure the Invoke has at least one field argument
for arg in node.symbol_table.argument_list:
if isinstance(arg.datatype, DataTypeSymbol):
if arg.datatype.name == "r2d_field":
break
else:
raise TransformationError(
f"GOConstLoopBoundsTrans can not transform invoke "
f"'{node.name}' because it does not have any field arguments.")
[docs] def apply(self, node, options=None):
''' Modify the GOcean kernel loops in a GOInvokeSchedule to use
common constant loop bound variables.
:param node: the GOInvokeSchedule of which all loops will get the \
constant loop bounds.
:type node: :py:class:`psyclone.gocean1p0.GOInvokeSchedule`
:param options: a dictionary with options for transformations.
:type options: Optional[Dict[str, Any]]
'''
self.validate(node, options=options)
i_stop = node.symbol_table.new_symbol(
"istop", symbol_type=DataSymbol, datatype=INTEGER_TYPE)
j_stop = node.symbol_table.new_symbol(
"jstop", symbol_type=DataSymbol, datatype=INTEGER_TYPE)
# Get a field argument from the argument list (we checked there
# is at least one on the validation method)
for arg in node.symbol_table.argument_list:
if isinstance(arg.datatype, DataTypeSymbol):
if arg.datatype.name == "r2d_field":
field = arg
break
# Look-up the loop bounds using the first field object in the
# list
api_config = Config.get().api_conf("gocean1.0")
xstop = api_config.grid_properties["go_grid_xstop"].fortran \
.format(field)
ystop = api_config.grid_properties["go_grid_ystop"].fortran \
.format(field)
# Add the assignments of the bounds to their variables at the
# beginning of the invoke.
assign1 = Assignment.create(
Reference(i_stop),
StructureReference.create(
field, xstop.split('%')[1:]))
assign1.preceding_comment = "Look-up loop bounds"
assign2 = Assignment.create(
Reference(j_stop),
StructureReference.create(
field, ystop.split('%')[1:]))
node.children.insert(0, assign1)
node.children.insert(1, assign2)
# Fortran reader needed to parse constructed bound expressions
fortran_reader = FortranReader()
# Update all GOLoop bounds with the new variables
for loop in node.walk(GOLoop):
# Chose the variable depending if it is an inner or outer loop
if loop.loop_type == "inner":
stop = i_stop.name
elif loop.loop_type == "outer":
stop = j_stop.name
else:
raise InternalError(
f"Found a loop with loop_type '{loop.loop_type}' but the "
f"only expected values are 'inner' or 'outer'.")
# Get the bounds map
bounds = loop.bounds_lookup[loop.index_offset][loop.field_space][
loop.iteration_space][loop.loop_type]
# Set the lower bound
start_expr = bounds["start"].format(start='2', stop=stop)
start_expr = "".join(start_expr.split()) # Remove white spaces
# This common case is a bit of compile-time computation
# but it helps with fixing all of the test cases.
if start_expr == "2-1":
start_expr = "1"
psyir = fortran_reader.psyir_from_expression(
start_expr, node.symbol_table)
loop.children[0].replace_with(psyir)
# Set the upper bound
stop_expr = bounds["stop"].format(start='2', stop=stop)
stop_expr = "".join(stop_expr.split()) # Remove white spaces
if stop_expr == "2-1":
stop_expr = "1"
psyir = fortran_reader.psyir_from_expression(
stop_expr, node.symbol_table)
loop.children[1].replace_with(psyir)