[Haskell-beginners] maybe this could be improved?

[Patrick LeBoutillier]

On Thu, Nov 12, 2009 at 5:31 PM, Michael Mossey <mpm at alumni.caltech.edu> wrote:
> Hi, Thanks for your help and it looks like you identified some conditions
> that could be removed. There is one change necessary, I think.
>
> closest a b = if (inPitch - a) < (b - inPitch) then a else b

Yes, of course. I just happens that in the test code (testMap2) it
gives the same answer...

Patrick



>
> Patrick LeBoutillier wrote:
>>
>> Michael,
>>
>> Here's my stab at it, not sure if it's really better though:
>>
>>
>> findClosestPitch :: SampleMap -> Pitch -> ErrorT String Identity Pitch
>> findClosestPitch samples inPitch = do
>>  when (M.null samples) $ throwError "Was given empty sample table."
>>  case M.splitLookup inPitch samples of
>>    (_, Just _, _) -> return inPitch
>>    (ml, _, mh)    -> return $ approxPitch ml mh
>>    where
>>      approxPitch ml mh | M.null ml = fst . M.findMin $ mh
>>      approxPitch ml mh | M.null mh = fst . M.findMax $ ml
>>      approxPitch ml mh             = closest (fst . M.findMax $ ml)
>> (fst . M.findMin $ mh)
>>        where closest a b = min (inPitch - a) (b - inPitch)
>>
>>
>> I tried to separate the approximation part from the rest of the code,
>> and used a bit of deduction to eliminate (hopefully correctly...) some
>> of the testing conditions.
>> Anyways, I had fun doing working on this, and I learned a bit about
>> computerized music as well!
>>
>>
>> Thanks,
>>
>> Patrick
>>
>>
>>
>



-- 
=====================
Patrick LeBoutillier
Rosemère, Québec, Canada