[PATCH 0/5] Fix histogram for some (corner) cases

[Laurent Pinchart]

On Tue, Apr 01, 2025 at 12:30:04AM +0300, Laurent Pinchart wrote:
> On Mon, Mar 24, 2025 at 06:07:35PM +0100, Stefan Klug wrote:
> > Hi all,
> > 
> > during my work on WDR I stumbled over a few non-linearities when dealing
> > with small inter quantile mean ranges. These led to hard to handle
> > oscillations. This series adds a testcase for the histogram class and
> > fixes the related issues.
> > 
> > Patch 1 adds the basic tests that pass with the current implementation.
> > 
> > Patch 2-3 fix issues in the quantile() implementation and add
> > corresponding tests.
> > 
> > Patch 4-5 fix issues in the interQuantileMean() implementation and also
> > add tests.
> > 
> > I added the tests after the fixes, so that I don't have to toggle should_fail
> > in the meson.build file all the time (And CI doesn't test every commit anyways).
> 
> Doesn't it ? The build-history test is supposed to do just that.

Ah, you meant that CI doesn't run unit tests for every commit. That's
true.

> > To test that in review, I believe the easiest is to temporarily revert the
> > corresponding fix and see the test fail.
> 
> should_fail is meant exactly for this :-)

should_fail isn't meant for CI. Adding tests first ensures that the test
fails. This is meant to avoid adding a buggy test that doesn't actually
catch the issue it's supposed to catch. I would much prefer having the
tests added first.

> > Stefan Klug (5):
> >   test: ipa: libipa: Add histogram tests
> >   libipa: histogram: Fix quantile() calculation for fractional results
> >   test: ipa: libipa: histogram: Add tests for quantile() returning a
> >     fraction
> >   libipa: histogram: Fix interQuantileMean() for small ranges
> >   test: ipa: libipa: histogram: Add tests for small inter quantile mean
> >     ranges
> > 
> >  src/ipa/libipa/histogram.cpp  | 23 ++++++------
> >  test/ipa/libipa/histogram.cpp | 66 +++++++++++++++++++++++++++++++++++
> >  test/ipa/libipa/meson.build   |  1 +
> >  3 files changed, 80 insertions(+), 10 deletions(-)
> >  create mode 100644 test/ipa/libipa/histogram.cpp

-- 
Regards,

Laurent Pinchart