tests: Mention binomial coefficient in hash tests.

This just makes it a bit easier for someone coming in fresh to do some searches and figure out what the description means. Signed-off-by: Joe Stringer <[email protected]> Acked-by: Ben Pfaff <[email protected]>
subashd · Sep 30, 2014 · a2b59fd · a2b59fd
1 parent ec47af5
commit a2b59fd
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/tests/test-hash.c b/tests/test-hash.c
@@ -129,7 +129,9 @@ test_hash_main(int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
      * Given a random distribution, the probability of at least one collision
      * in any set of 11 bits is approximately
      *
-     *                      1 - ((2**11 - 1)/2**11)**C(33,2)
+     *                      1 - (proportion of same_bits)
+     *                          **(binomial_coefficient(n_bits_in_data + 1, 2))
+     *                   == 1 - ((2**11 - 1)/2**11)**C(33,2)
      *                   == 1 - (2047/2048)**528
      *                   =~ 0.22
      *