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Has someone written a macro that rounds a float to the nearest integer?
Thanks!
Mike
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On 5/27/2021 7:20 AM, Mike Horvath wrote:
> Has someone written a macro that rounds a float to the nearest integer?
> Thanks!
>
>
> Mike
Or, to the nearest multiple of n, where n is any number.
Mike
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Am 27.05.2021 um 13:20 schrieb Mike Horvath:
> Has someone written a macro that rounds a float to the nearest integer?
`floor(FOO + 0.5)` should do the trick.
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Am 27.05.2021 um 13:31 schrieb Mike Horvath:
>> Has someone written a macro that rounds a float to the nearest
>> integer? Thanks!
...
> Or, to the nearest multiple of n, where n is any number.
try `floor(FOO / N + 0.5) * N`.
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On 5/27/2021 9:17 AM, clipka wrote:
> Am 27.05.2021 um 13:31 schrieb Mike Horvath:
>>> Has someone written a macro that rounds a float to the nearest
>>> integer? Thanks!
> ...
>> Or, to the nearest multiple of n, where n is any number.
>
> try `floor(FOO / N + 0.5) * N`.
I found this on web and adapted it to POV:
#macro round(number, base)
(((number + base/2) / base) * base)
#end
Not sure which of the two is preferable.
Mike
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Am 27.05.2021 um 15:32 schrieb Mike Horvath:
>>> Or, to the nearest multiple of n, where n is any number.
>>
>> try `floor(FOO / N + 0.5) * N`.
>
> I found this on web and adapted it to POV:
>
> #macro round(number, base)
> (((number + base/2) / base) * base)
> #end
>
> Not sure which of the two is preferable.
You mean, aside from the fact that yours won't work, unless you put a
`floor` between the first and second opening parentheses? ;)
Mine, I'd guess. It is comprised of only 10 tokens as opposed to 16
(including the missing `floor`), and only 3 variable references as
opposed to 4, so it will parse faster. The expression tree is also a bit
simpler, so it will also execute faster, even if written as a function
rather than a macro. (Remember, macros are parsed over and over again
every time they are called. In general, functions are faster.)
Yours - especially with the lack of `floor` - looks like it was
specifically designed for operating on purely integer values (i.e. not
only is `number` expected to be an integer, but each operation
automatically rounds down to an integer). In such a setting, it would be
spot-on, to the point that you couldn't come up with a more efficient
solution than that.
POV-Ray doesn't even know what an integer is.
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Le 2021-05-27 à 09:14, clipka a écrit :
> Am 27.05.2021 um 13:20 schrieb Mike Horvath:
>> Has someone written a macro that rounds a float to the nearest integer?
>
> `floor(FOO + 0.5)` should do the trick.
«ceil(FOO - 0.5)» should also work.
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Am 27.05.2021 um 20:50 schrieb Alain Martel:
> Le 2021-05-27 à 09:14, clipka a écrit :
>> Am 27.05.2021 um 13:20 schrieb Mike Horvath:
>>> Has someone written a macro that rounds a float to the nearest integer?
>>
>> `floor(FOO + 0.5)` should do the trick.
>
> «ceil(FOO - 0.5)» should also work.
In a technical sense, yes. However, values exactly halfway between would
be rounded down, rather than up as per the common convention(*).
(For positive values, that is. For negative values, the common
convention is to round such numbers towards negative infinity, making
the `ceil`-based formula more true to conventional rounding in the
negative domain.)
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