chksum_stats_t Derived Type

type, public :: chksum_stats_t

One field’s reduction bundle.


Components

Type Visibility Attributes Name Initial
integer(kind=int64), public :: bits = 0_int64

Decomposition-invariant bitcount: the wrapped int64 sum of POPCNT over the IEEE-754 bit pattern of every reduced element. Unlike the FP total (only stable within one binary), integer addition is EXACTLY associative + commutative, so this is identical across rank counts and loop orders — the authoritative log-diff signal for a decomposition / halo bug.
real(kind=wp), public :: maxv = 0.0_wp

NaN-blind extrema (see module docstring).
real(kind=wp), public :: minv = 0.0_wp
integer, public :: nonfin = 0

Count of non-finite entries — the corruption signal.
real(kind=wp), public :: total = 0.0_wp

Plain (non-compensated) sum — bitwise-stable per build, so log-diffable between two runs of the SAME binary; NaN when the field is contaminated.

Source Code

   type :: chksum_stats_t
      !! One field's reduction bundle.
      real(wp) :: total = 0.0_wp
         !! Plain (non-compensated) sum — bitwise-stable per build, so
         !! log-diffable between two runs of the SAME binary; NaN when
         !! the field is contaminated.
      real(wp) :: minv = 0.0_wp
      real(wp) :: maxv = 0.0_wp
         !! NaN-blind extrema (see module docstring).
      integer :: nonfin = 0
         !! Count of non-finite entries — the corruption signal.
      integer(int64) :: bits = 0_int64
         !! Decomposition-invariant bitcount: the wrapped int64 sum of
         !! POPCNT over the IEEE-754 bit pattern of every reduced element.
         !! Unlike the FP `total` (only stable within one binary),
         !! integer addition is EXACTLY associative + commutative, so this
         !! is identical across rank counts and loop orders — the
         !! authoritative log-diff signal for a decomposition / halo bug.
   end type chksum_stats_t