[PD] more about float limitation (was: weird float/add limitation)

Alexandre Torres Porres porres at gmail.com
Thu Jan 29 17:40:51 CET 2015


6 significant digits also allow a number like  0.000123456

2015-01-29 14:17 GMT-02:00 Alexandre Torres Porres <porres at gmail.com>:

> Well, thanks everyone.
>
> And now for some related issues.
>
> Pd can only represent up to 6 significant digits, so they say. For
> example, in a message, you can have a number with up to 5 decimal places,
> like: -5.29314e+12
>
> but it does have a better internal resolution, if you compare 4 / 3 to
> 1.33333 you'll see 4 / 3 is higher ( try [expr 4./3 > 1.33333] and check).
>
> So, what's this internal resolution? And why can't you have the same
> resolution in a message?
>
> thanks
>
> 2015-01-28 16:06 GMT-02:00 Martin Peach <chakekatzil at gmail.com>:
>
>> On Wed, Jan 28, 2015 at 12:00 PM, Cyrille Henry <ch at chnry.net> wrote:
>>
>>>
>>>
>>> Le 28/01/2015 17:47, Alexandre Torres Porres a écrit :
>>>
>>>>  > it's a limitation of 32 bit float
>>>>
>>>> I thought so, but same happens when I use the new Pd Vanilla 64 bits...
>>>>
>>> this mean that it's compiled for 64 bit CPU, not that float are store on
>>> 64 bits
>>>
>> Also last time I checked, Pd saves floats by first printing them to 6
>> digit precision, so they have even less range than a 'float' type.
>> You could use an object made with pdlua to manipulate large
>> floating-point numbers, as there is no(?) limit to the size of a float in
>> lua.
>>
>> Martin
>>
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>
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