Well, I'm trying to point out that it ain't "broken", the object works... whatever its code is. I'm just trying to figure out the code to clone it.
2015-06-19 22:55 GMT-03:00 Joel Matthys <[email protected]>: > I just don't see the value of trying to make it compatible with broken > code in Max. > > Joel > > > On 06/19/2015 08:47 PM, Alexandre Torres Porres wrote: > > yeah, I see all that, but the problem is trying to clone it as it is in > Max for the sake of compatibility. > > I wouldn't say that the classic mode is "wrong", it may be not good for > the purpose, but it's an arbitrary mathematical formula, so it is what it > is. > > The problem is that I'm not being able to get the result the object > spits out with the formula given in the reference. > > So my question is just making it sure that the given formula is wrong, > and that it doesn't give what the object actually does. > > moreover, the idea is to keep compatibility, at first, with Max5. In > Max7 the scale object will still give the same results (as default, by the > way), so even if it was for the sake of making it compatible with Max7, > we'd still need to make it work. But the thing is that the new "not > classic" mode was introduced only in Max6. So, for the actual purpose, > we're only caring about the classic mode compatibility. > > did you check if the formula in the reference is actually wrong, in the > sense it won't give the results given by the object? Were you able to spot > a parenthesis out of place or something that, if changed, would give the > expected result? > > thanks > > cheers > > 2015-06-19 22:25 GMT-03:00 Joel Matthys <[email protected]>: > >> 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; >> >> >> >> _______________________________________________pd-l...@lists.iem.at >> mailing list >> UNSUBSCRIBE and account-management -> >> http://lists.puredata.info/listinfo/pd-list >> >> >> > >
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