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Follow the directions under "contributing" in the [Commons Math Developers Guide|http://jakarta.apache.org/commons/math/developers.html Commons Math Developers Guide]. Feedback and contributions from all interested parties are welcome. Extensive Java or mathematical knowledge is not required to participate (though some knowledge of one or the other is certainly helpful 
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2. Can code derived from "Numerical Recipes" routines be included in commons-math?
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Algorithms implemented in "Numerical Recipes" are \[http://www.numerical-recipes.com/infotop.html#distinfo licensed under terms\] that are incompatible with the Apache license. As such, commons-math can not contain any code derived from these routines. The precedent we have established is to not allow any code developed using NR as a source and instead find alternate citations for the algorithms detailed in NR.