stats: Add support for the interquartile range (IQR)

IQR is a good measure of dispersion.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/tests/igt_stats.c b/lib/tests/igt_stats.c
index c4c67760..c0649f33 100644
--- a/lib/tests/igt_stats.c
+++ b/lib/tests/igt_stats.c
@@ -102,6 +102,7 @@ static void test_quartiles(void)
 	igt_assert_eq_double(q2, 40);
 	igt_assert_eq_double(q3, 42.5);
 	igt_assert_eq_double(igt_stats_get_median(&stats), 40);
+	igt_assert_eq_double(igt_stats_get_iqr(&stats), 42.5 - 25.5);
 
 	igt_stats_fini(&stats);
 
@@ -114,6 +115,7 @@ static void test_quartiles(void)
 	igt_assert_eq_double(q2, 37.5);
 	igt_assert_eq_double(q3, 40);
 	igt_assert_eq_double(igt_stats_get_median(&stats), 37.5);
+	igt_assert_eq_double(igt_stats_get_iqr(&stats), 40 - 15);
 
 	igt_stats_fini(&stats);
 }