JMSL Tutorial: MusicShape

One of the great joys of hacking JMSL is developing algorithms that generate interesting MusicShapes. So let's spend a little time doing just that.

We will build a MusicShape which displays an increasing random variation from a central value. So the algorithm to generate element[i] will depend partially on the index i itself (ie the value is a function of the index).

The key to this algorithm is the ChoosePlusMinus(int arg) method in the JMSLRandom class. This method chooses a random int between +arg and -arg (there is also a version for double). A fragment illustrates:

for (int i=0; i < numberOfElements; i++){
    double value = centralValue + JMSLRandom.choosePlusMinus(i);
    myShape.add(value);
}

You see that for example, the 50th value generated will be the result of adding centralValue to a random number between -50 and 50, as the screen shot below shows.



View the source of this example here.

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  (C) Phil Burk and Nick Didkovsky, All Rights Reserved
  JMSL is based upon HMSL (C) Phil Burk, Larry Polansky and David Rosenboom.