loki.transform.transform_loop

Collection of utility routines that provide loop transformations.

Functions

eliminate_variable(polyhedron, index_or_variable)

Eliminate a variable from the polyhedron.

generate_loop_bounds(iteration_space, ...)

Generate loop bounds according to a changed iteration order.

get_loop_components(loops)

Helper routine to extract loop variables, ranges and bodies of list of loops.

get_nested_loops(loop, depth)

Helper routine to extract all loops in a loop nest.

loop_fission(routine[, promote, ...])

Search for !$loki loop-fission pragmas in loops and split them.

loop_fusion(routine)

Search for loops annotated with the loki loop-fusion pragma and attempt to fuse them into a single loop.

loop_interchange(routine[, project_bounds])

Search for loops annotated with the loki loop-interchange pragma and attempt to reorder them.

pragma_ranges_to_loop_ranges(parameters, scope)

Convert loop ranges given in the pragma parameters from string to a tuple of LoopRange objects.

Classes

FissionTransformer(loop_pragmas[, active])

Bespoke transformer that splits loops or loop nests at !$loki loop-fission pragmas.

loop_interchange(routine, project_bounds=False)

Search for loops annotated with the loki loop-interchange pragma and attempt to reorder them.

Note that this effectively just exchanges variable and bounds for each of the loops, leaving the rest (including bodies, pragmas, etc.) intact.

loop_fusion(routine)

Search for loops annotated with the loki loop-fusion pragma and attempt to fuse them into a single loop.

loop_fission(routine, promote=True, warn_loop_carries=True)

Search for !$loki loop-fission pragmas in loops and split them.

The expected pragma syntax is !$loki loop-fission [collapse(n)] [promote(var-name, var-name, ...)] where collapse(n) gives the loop nest depth to be split (defaults to n=1) and promote optionally specifies a list of variable names to be promoted by the split iteration space dimensions.

Parameters:
  • routine (Subroutine) – The subroutine in which loop fission is to be applied.

  • promote (bool, optional) – Try to automatically detect read-after-write across fission points and promote corresponding variables. Note that this does not affect promotion of variables listed directly in the pragma’s promote option.

  • warn_loop_carries (bool, optional) – Try to automatically detect loop-carried dependencies and warn when the fission point sits after the initial read and before the final write.