parquet_debug_sort_sweep_less Interface

interface
public module function parquet_debug_sort_sweep_less(keys, nrows, nreps) result(count)

Arguments

Type IntentOptional Attributes Name
type(pf_sort_keys), intent(in) :: keys

the built key set.
integer(kind=int64), intent(in) :: nrows

rows to walk per pass.
integer(kind=int64), intent(in) :: nreps

passes.

Return Value integer(kind=int64)

how many pairs compared less; -1 if unusable.

Description

Test-only sweep of nreps passes of nrows comparisons, returning a checksum.

For bench/benchmark_sort_comparator.f90, which needs the comparator's own cost rather than the cost of reaching it: at ~5 ns per comparison a per-call harness measures its own overhead. The C++ twin is parquet_debug_sort_sweep_less_cpp in src/parquet_wrapper.cpp and the two loops are deliberately identical, down to the stride walk — their checksums must agree, which is what proves they did the same work. Neither uses mod on a runtime divisor: that is an integer division, and it would cost more than the comparison being timed.