in this situation, i use a "slow" metro, trigering a random with the correct scale, and filter the value with a line3 object (the time of the line is the same than the metro time) change "smoothness" with the metro tempo.
cyrille Le 22/08/2010 21:17, Matteo Sisti Sette a écrit :
Hi, In my patches (especially in visual ones) I often need some value to randomly "oscillate", or change smoothly, between two extremes, at regular intervals (e.g. change every frame). For this purpose I often use filtered noise: [random] followed by a filter of the kind y[n]=a*y[n-1]+(1-a)*x[n] with 0<a<1 This is fine when I don't need to have a very precise control over the range and especially when it doesn't have to be controlled dinamically, so I just adjust the "smoothness" and compensate the gain by trial and error. But when I need to easily control the minimum and maximum and have a parameter that controls "smoothness" in a natural way, I am not very satisfied with this approach. Another technique I use is to have a random increment (which can be positive or negative) added to the current value; then I can force it to "bounce" when it reaches either extreme. Same as above: it works but is often unsatisfying. What do you usually use in these situations? I'd prefer a roughly uniform distribution of the final result over a gaussian one, or at least one that would have a minimum and a maximum without clipping (the problem with a gaussian is that you either get a peak in probability of the extreme values, or in order to avoid them, you get very low density for any value near them).... I know this is not a well-defined problem, that there are hundreds of answers with advantages and disadvantages depending on the application; but I guess many of you have often needed something similar and I'd like to hear what are your favourite solutions. thanks m. _______________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
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