diff options
| author | Damien Lespiau <damien.lespiau@intel.com> | 2015-06-25 23:59:21 +0100 |
|---|---|---|
| committer | Damien Lespiau <damien.lespiau@intel.com> | 2015-06-27 16:03:27 +0100 |
| commit | 515cec1210764241153f5d46d70ba5e943201b14 (patch) | |
| tree | 4b7866c6de7bfbf32423bbbe30dde0af78bcefb8 /lib/tests | |
| parent | 05c10f940f9df3a5b24e2a0b476052fbe5a22282 (diff) | |
stats: Add a way to retrieve the standard deviation
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Diffstat (limited to 'lib/tests')
| -rw-r--r-- | lib/tests/Makefile.am | 2 | ||||
| -rw-r--r-- | lib/tests/igt_stats.c | 33 |
2 files changed, 34 insertions, 1 deletions
diff --git a/lib/tests/Makefile.am b/lib/tests/Makefile.am index e59065bb..938d2ab0 100644 --- a/lib/tests/Makefile.am +++ b/lib/tests/Makefile.am @@ -15,5 +15,5 @@ AM_CFLAGS = $(DRM_CFLAGS) $(CWARNFLAGS) \ LDADD = ../libintel_tools.la $(PCIACCESS_LIBS) $(DRM_LIBS) $(LIBUNWIND_LIBS) -LDADD += $(CAIRO_LIBS) $(LIBUDEV_LIBS) $(GLIB_LIBS) +LDADD += $(CAIRO_LIBS) $(LIBUDEV_LIBS) $(GLIB_LIBS) -lm AM_CFLAGS += $(CAIRO_CFLAGS) $(LIBUDEV_CFLAGS) $(GLIB_CFLAGS) diff --git a/lib/tests/igt_stats.c b/lib/tests/igt_stats.c index c20b4537..172e4b32 100644 --- a/lib/tests/igt_stats.c +++ b/lib/tests/igt_stats.c @@ -45,7 +45,40 @@ static void test_mean(void) igt_stats_fini(&stats); } +/* + * Taken from the "Basic examples" section of: + * https://en.wikipedia.org/wiki/Standard_deviation + */ +static void test_std_deviation(void) +{ + igt_stats_t stats; + double mean, variance, std_deviation; + + igt_stats_init(&stats, 8); + + igt_stats_push(&stats, 2); + igt_stats_push(&stats, 4); + igt_stats_push(&stats, 4); + igt_stats_push(&stats, 4); + igt_stats_push(&stats, 5); + igt_stats_push(&stats, 5); + igt_stats_push(&stats, 7); + igt_stats_push(&stats, 9); + + mean = igt_stats_get_mean(&stats); + igt_assert(mean == (2 + 3 * 4 + 2 * 5 + 7 + 9) / 8.); + + variance = igt_stats_get_variance(&stats); + igt_assert(variance == 4); + + std_deviation = igt_stats_get_std_deviation(&stats); + igt_assert(std_deviation == 2); + + igt_stats_fini(&stats); +} + igt_simple_main { test_mean(); + test_std_deviation(); } |