Stat overflow

[jmid]

This fixes a rare overflow in the histogram labels (and simplifies a couple of other things).

Before (notice the negative labels on the last bucket):

utop # #require"qcheck";;
utop # openQCheck;;
utop # let t =Test.make ~count:1_000 (add_stat ("dist",fun x -> x) (oneof [small_int_corners ();int])) (fun_ -> true);;
valt : Test.t=QCheck.Test.Test<abstr>
utop # QCheck_runner.run_tests~verbose:true [t];;
random seed: 153870556
generated errorfailpass/totaltimetestname
[✓] 1000001000/10000.0s anon_test_1+++Statsfor anon_test_1 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
stats dist:
num: 1000, avg: -55083208105414400.00, stddev: 1847115855773139200.00, median 9, min -4590718933436425025, max 4611686018427387903-4590718933436425025..-4130598685843234370: ## 26-4130598685843234369..-3670478438250043714: # 13-3670478438250043713..-3210358190656853058: ### 37-3210358190656853057..-2750237943063662402: ### 30-2750237943063662401..-2290117695470471746: ## 27-2290117695470471745..-1829997447877281090: ## 24-1829997447877281089..-1369877200284090434: ## 27-1369877200284090433.. -909756952690899778: ## 27-909756952690899777.. -449636705097709122: ## 21-449636705097709121.. 10483542495481534: ####################################################### 53110483542495481535.. 470603790088672190: ## 21470603790088672191.. 930724037681862846: ## 27930724037681862847.. 1390844285275053502: ## 241390844285275053503.. 1850964532868244158: ## 251850964532868244159.. 2311084780461434814: ## 282311084780461434815.. 2771205028054625470: ## 232771205028054625471.. 3231325275647816126: ## 233231325275647816127.. 3691445523241006782: ## 253691445523241006783.. 4151565770834197438: # 174151565770834197439.. 4611686018427387903: ## 24-4611686018427387713..-4151565770834197058: 0================================================================================
success (ran 1 tests)
- : int=0

After the change it behaves better:

utop # openQCheck;;
utop # QCheck_runner.set_seed 153870556;;
random seed: 153870556- : unit=()
utop # let t =Test.make ~count:1_000 (add_stat ("dist",fun x -> x) (oneof [small_int_corners ();int])) (fun_ -> true);;
valt : Test.t=QCheck2.Test.Test<abstr>
utop # QCheck_runner.run_tests~verbose:true [t];;
generated errorfailpass/totaltimetestname
[✓] 1000001000/10000.0s anon_test_1+++Statsfor anon_test_1 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
stats dist:
num: 1000, avg: -55083208105414400.00, stddev: 1847115855773139200.00, median 9, min -4590718933436425025, max 4611686018427387903-4590718933436425025..-4130598685843234370: ## 26-4130598685843234369..-3670478438250043714: # 13-3670478438250043713..-3210358190656853058: ### 37-3210358190656853057..-2750237943063662402: ### 30-2750237943063662401..-2290117695470471746: ## 27-2290117695470471745..-1829997447877281090: ## 24-1829997447877281089..-1369877200284090434: ## 27-1369877200284090433.. -909756952690899778: ## 27-909756952690899777.. -449636705097709122: ## 21-449636705097709121.. 10483542495481534: ####################################################### 53110483542495481535.. 470603790088672190: ## 21470603790088672191.. 930724037681862846: ## 27930724037681862847.. 1390844285275053502: ## 241390844285275053503.. 1850964532868244158: ## 251850964532868244159.. 2311084780461434814: ## 282311084780461434815.. 2771205028054625470: ## 232771205028054625471.. 3231325275647816126: ## 233231325275647816127.. 3691445523241006782: ## 253691445523241006783.. 4151565770834197438: # 174151565770834197439.. 4611686018427387903: ## 24================================================================================
success (ran 1 tests)
- : int=0

I'm still not too happy about the statistics code, but this is at least a step in the right direction.

[c-cube]

Good catch, thank you. I don't like the stats code either, but it has never been clean and it's the best we have right now :)