[PD] help cloning max's scale

Sat Jun 20 05:06:09 CEST 2015

> To be honest, I don't think the non classic mode is that much
> sensible. It'd make much more sense to me to specify a power
> exponential.

I take this back, because that what it does after all, you specify the
power exponential :)

I still think we need to clone the classic mode behavior, but I'm surely
including this non classic feature from Max7, cause it is as sensible as it
gets.

cheers

2015-06-19 23:36 GMT-03:00 Alexandre Torres Porres <porres at gmail.com>:

> > There's no way mapping 13.3 from 0-127 to -1 to 1
> > should result in something so close to -1
>
> well, there wouldn't be a way if it were a linear scaling... but it's a
> logarithmic scale, so it'll do what it does.
>
> > Just try a few different exponents and
> > you'll see that there's a bug in the Max code.
>
> which bug exactly? I tried other values close to the "typical value" they
> mention (1.06) and it doesn't seem weird to me. Not typical values will
> given untypical and not so useful results, but they warn you about it.
>
> > there are lots of bug reports out there about it.
>
> About the object or the conversion formula? cause if it is about the
> object, it could be anything. Now, if the object does not convert according
> to the supposed math, it'd be reasonable that they'd have it fixed
> eventually. Is this really the case? I hope you could be more specific
> about the issue. I'd like to know that please, now that I'm working with
> this.
>
> > Switch off classic mode in the inspector in Max7, and you
> > get the same result as expr above, the very sensible -0.817072.
>
> To be honest, I don't think the non classic mode is that much sensible.
> It'd make much more sense to me to specify a power exponential.
>
> Anyway, it may be more sensible after all, but this fact alone is not
> enough to say the other one is "wrong" or "broken" - you can just say it
> isn't "sensible"... which is true.
>
> What we know is that the given formula in the reference for the non
> classic mode is in accordance to what the object outputs. I had tested that
> by the way, and saw it was accurate.
>
> I'm just asking to make sure if the other given formula given in the
> reference is actually wrong, or if I made a mistake. It seems clear for us
> that it is not outputting what the object is, so the reference seems just
> wrong.
>
> If the reference is wrong, it doesn't mean the object is "broken" or
> "wrong". And talking about being sensible, the output of the given formula
> is even crazier and all... so it's not like the object should output that,
> it's more like "hey, the reference is wrong, and we don't know the formula
> to clone it!"
>
> About the other inquiry on what would I want to clone an object that
> behaves arguably insensibly, the answer is just that I'd like to clone it
> for the purpose of cloning it. Whatever it is, I'd like to make an exact
> copy of it. That's the purpose of cyclone after all.
>
> cheers
>
>
> 2015-06-19 22:25 GMT-03:00 Joel Matthys <jwmatthys at gmail.com>:
>
>>  You're using the [scale] formula from @classic_mode in Max7, which
>> exists for compatibility with IRCAM, but it's clearly wrong. (There's no
>> way mapping 13.3 from 0-127 to -1 to 1 should result in something so close
>> to -1. Just try a few different exponents and you'll see that there's a bug
>> in the Max code. And there are lots of bug reports out there about it.)
>>
>> That's why they introduced an alternate mode for [scale] in Max, which
>> can be switch in the Inspector.
>>
>> For non-classic (modern) mode, the documentation gives you this equation:
>>
>> ((x-in_low)/(in_high-in_low) == 0) ? out_low :
>> (((x-in_low)/(in_high-in_low)) > 0) ? (out_low + (out_high-out_low) *
>> ((x-in_low)/(in_high-in_low))^exp) : ( out_low + (out_high-out_low) *
>> -((((-x+in_low)/(in_high-in_low)))^(exp)))
>>
>> Translated to expr as:
>>
>> [expr if ((($f1-in_low)/(in_high-in_low)==0), out_low, if
>> ((($f1-in_low)/(in_high-in_low)>0),
>> out_low+(out_high-out_low)*pow(($f1-in_low)/(in_high-in_low), power),
>> out_low+(out_high-out_low)*-1*pow((-1*$f1+in_low)/(in_high-in_low),
>> power)))]
>>
>> Switch off classic mode in the inspector in Max7, and you get the same
>> result as expr above, the very sensible -0.817072.
>>
>> Joel
>>
>>
>> On 06/19/2015 05:39 PM, Alexandre Torres Porres wrote:
>>
>>  Howdy, so I'm cloning the scale object from Max, to make an object and
>> include in the cyclone library. It converts range input (low_in / high_in)
>> to a range output (low_out / high_out). It has a logarithmic curve for
>> rescaling according to a fifth argument/inlet. I did copy into expr the
>> formula described in the reference of Max6/7 (max's 5 was just wrong,
>> copied from [linedrive]) - well, it didn't work! Would anyone know if I'm
>> doing something wrong or if the reference is not telling the truth?
>>
>> The formula, as described in the reference is: (out_low + (out_high-out_low)
>> * ( (out_high - out_low) * exp(-1 * (in_high-in_low) * log(power)) * exp(x
>> * log(power)) ))
>>
>>
>>  Here's my patch with that formula into expr. The output with the
>> parameters I have should be -0.997347 - as that's the output I get in Max.
>> But instead, it's giving -0.994694...
>>
>>
>>  thanks
>>
>>
>>
>>
>>  =================
>>
>>
>>  #N canvas 24 23 488 340 10;
>>
>> #X obj 215 154 v out_low;
>>
>> #X obj 233 132 v out_high;
>>
>> #X obj 288 110 v power;
>>
>> #X obj 152 130 v in_high;
>>
>> #X obj 115 153 v in_low;
>>
>> #X floatatom 58 248 0 0 0 0 - - -;
>>
>> #X obj 58 197 expr (out_low + (out_high-out_low) * ( (out_high - out_low)
>>
>> * exp(-1*(in_high-in_low)*log(power)) * exp($f1*log(power)) ));
>>
>> #X msg 115 102 0;
>>
>> #X msg 152 102 127;
>>
>> #X msg 215 99 -1;
>>
>> #X msg 249 97 1;
>>
>> #X msg 288 86 1.06;
>>
>> #X obj 90 31 loadbang;
>>
>> #X obj 90 60 t b b;
>>
>> #X msg 58 107 13.3;
>>
>> #X connect 6 0 5 0;
>>
>> #X connect 7 0 4 0;
>>
>> #X connect 8 0 3 0;
>>
>> #X connect 9 0 0 0;
>>
>> #X connect 10 0 1 0;
>>
>> #X connect 11 0 2 0;
>>
>> #X connect 12 0 13 0;
>>
>> #X connect 13 0 14 0;
>>
>> #X connect 13 1 11 0;
>>
>> #X connect 13 1 10 0;
>>
>> #X connect 13 1 9 0;
>>
>> #X connect 13 1 8 0;
>>
>> #X connect 13 1 7 0;
>>
>> #X connect 14 0 6 0;
>>
>>
>>
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>
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