thank you. I will try to keep this last sentence in mind.


----- Original Message ----- 
From: "John ff" 
To: 
Sent: Monday, December 24, 2018 1:18 PM
Subject: Re: [Csnd] table opcodes


=frac(ipch)*100 is only an integer if ipch has no part in the thousandths. 
Rounding errors are all too easy to get.

⁣Sent from TypeApp

On Dec 24, 2018, 11:02, at 11:02, Andrea Strappa  wrote:
>yet from this formula:
>itabndx =frac(ipch)*100
>whole numbers should come out...
>
>----- Original Message ----- 
>From: "Andrea Strappa" 
>To: 
>Sent: Monday, December 24, 2018 11:48 AM
>Subject: Re: [Csnd] table opcodes
>
>
>yes, in my gen02 example
>itabndx =frac(ipch)*100
>don't work, it give unexpected results, but
>itabndx = round(frac(ipch)*100)
>work well.
>Maybe it is enough to add a note in the manual.
>
>----- Original Message ----- 
>From: "Victor Lazzarini" 
>To: 
>Sent: Sunday, December 23, 2018 9:36 PM
>Subject: Re: [Csnd] table opcodes
>
>
>But that's surely user error, is it not? If floor is not wanted, then
>interpolation is what is
>needed. Truncating table lookup uses floor not round.
>
>Victor Lazzarini
>Dean of Arts, Celtic Studies, and Philosophy
>Maynooth University
>Ireland
>
>> On 23 Dec 2018, at 20:20, jpff  wrote:
>>
>> The trouble with floor is rounding error as in the original message
>of
>> this thread.
>>
>> At least we should correct the manual and give a warning.
>>
>>> On Sun, 23 Dec 2018, Victor Lazzarini wrote:
>>>
>>> yes, I rewrote these for 6 to remove the need for power of two. I
>think
>>> floor is the correct operation; in any case, if we change it, we
>will
>>> change behaviour.
>>>
>>> Victor Lazzarini
>>> Dean of Arts, Celtic Studies, and Philosophy
>>> Maynooth University
>>> Ireland
>>>
>>>> On 23 Dec 2018, at 20:11, John  wrote:
>>>>
>>>> More code study shows that if we have a power-of-two table it uses
>the
>>>> fact, but if not resorts to more expensive ways.  So despite the
>>>> manual the opcodes are save for any table.  What they do is use
>floor
>>>> operation on the index so small rounding error as in the example in
>>>> question give unexpected results.
>>>>
>>
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