psyclone.domain.lfric.transformations.lfric_redundant_computation_trans

This module provides the LFRic redundant-computation transformation.

Classes

• LFRicRedundantComputationTrans: This transformation allows the user to modify a loop’s bounds so

class psyclone.domain.lfric.transformations.lfric_redundant_computation_trans.LFRicRedundantComputationTrans

This transformation allows the user to modify a loop’s bounds so that redundant computation will be performed. Redundant computation can result in halo exchanges being modified, new halo exchanges being added or existing halo exchanges being removed.

• This transformation should be performed before any parallelisation transformations (e.g. for OpenMP) to the loop in question and will raise an exception if this is not the case.

• This transformation can not be applied to a loop containing a reduction and will again raise an exception if this is the case.

• This transformation can only be used to add redundant computation to a loop, not to remove it.

• This transformation allows a loop that is already performing redundant computation to be modified, but only if the depth is increased.

Inheritance

apply(node, options=None, depth=None, **kwargs)

Apply the redundant computation transformation to the loop node. This transformation can be applied to loops iterating over ‘cells or ‘dofs’. if depth is set to a value then the value will be the depth of the field’s halo over which redundant computation will be performed. If depth is not set to a value then redundant computation will be performed to the full depth of the field’s halo.

Parameters:

• node (Loop) – the loop to transform.

• options (Optional[dict[str, Any]]) – a dictionary with options for transformations.

• depth (Union[int, DataNode, None]) – the depth to which to perform redundant computation. Default is None in which case the full halo depth is used.

• node_type_check (bool) – If the type of nodes enclosed in the loop should be tested to avoid including unsupported nodes in the transformation.

• verbose (bool) – whether to log the reason the validation failed, at the moment with a comment in the provided PSyIR node.

validate(node, options=None, **kwargs)

Perform various checks to ensure that it is valid to apply the RedundantComputation transformation to the supplied node

Parameters:

• node (Loop) – the supplied node on which we are performing validity checks.

• options (dict[str, Any] | None) – a dictionary with options for transformations.

• depth (int | psyclone.psyir.nodes.datanode.DataNode | None) – the depth to which to perform redundant computation. Default is None in which case the full halo depth is used.

• node_type_check (bool) – If the type of nodes enclosed in the loop should be tested to avoid including unsupported nodes in the transformation.

• verbose (bool) – whether to log the reason the validation failed, at the moment with a comment in the provided PSyIR node.

Raises:

• TransformationError – if the parent of the loop is a psyclone.psyir.nodes.Directive.

• TransformationError – if the parent of the loop is not a psyclone.psyir.nodes.Loop or a psyclone.psyGen.LFRicInvokeSchedule.

• TransformationError – if the parent of the loop is psyclone.psyir.nodes.Loop but the original loop does not iterate over ‘cells_in_colour’.

• TransformationError – if the parent of the loop is a psyclone.psyir.nodes.Loop but the parent does not iterate over ‘colours’.

• TransformationError – if the parent of the loop is a psyclone.psyir.nodes.Loop but the parent’s parent is not a psyclone.psyGen.LFRicInvokeSchedule.

• TransformationError – if this transformation is applied when distributed memory is not switched on.

• TransformationError – if the loop does not iterate over cells, dofs or colour.

• TransformationError – if the loop contains a kernel that operates on halo cells or only on owned cells/dofs.

• TransformationError – if the transformation is setting the loop to the maximum halo depth but the loop already computes to the maximum halo depth.

• TransformationError – if the transformation is setting the loop to the maximum halo depth but the loop contains a stencil access (as this would result in the field being accessed beyond the halo depth).

• TypeError – if the supplied depth value is of the wrong type.

• TransformationError – if the supplied depth value is less than 1.

• TransformationError – if the supplied depth value is not greater than 1 when a continuous loop is modified as this is the minimum valid value.

• TransformationError – if the supplied depth value is not greater than the existing depth value, as we should not need to undo existing transformations.

• TransformationError – if a depth value has been supplied but the loop has already been set to the maximum halo depth.