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ndelta.md

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Motivation

Often one runs a program twice - one way and the other way - to see how some parameter/input/mode/.. changes things. One then wants to compare the output of something reported - maybe resource consumption like time/space or success amounts or other accuracy parameters or other numeric outputs. So, the output is "largely" identical (or can be made so with sorting) except for "numbers" in different areas of the report. This situation is what ndelta is for.

Usage

  ndelta [optional-params] [paths: string...]

Replace numbers in token-compatible spots of paths[0] & paths[1] with (absolute
| ratio | relative | perCent) deltas.  To trap out-of-order data, differences in
context are highlighted unless sloppy is true.

  -k=, --kind=   DKind  ratio   DiffKind: absolute, ratio, relative, perCent
  -d=, --delims= string "white" repeatable delim chars
  -n=, --n=      int    3       FP digits to keep
  -s, --sloppy   bool   false   allow non-numerical context to vary silently

A relative difference here is the ratio - 1.0 while perCent is that multiplied by 100.

Presently, ndelta has some sanity checks (total token count equality) to help the report be meaningful in the way intended and a sloppy mode to let context/delimiters vary but be reported in the output.

Related Work

There is, of course, the ever-present diff possibly combined with my hldiff to highlight sections, but this only presents textual differences while one often wants numeric (one of the 4 kinds currently supported by ndelta). ndelta is a very simple program. Variants of it have surely been done many times. If me not mentioning one here bugs you, bug me and I'll mention it. :)