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https://issues.apache.org/jira/browse/MATH-1143?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14520131#comment-14520131
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Thomas Neidhart commented on MATH-1143:
---------------------------------------
Examples:
evaluation
{code}
public static double derivative(UnivariateDifferentiableFunction f, double
x, int order) {
DerivativeStructure ds = f.value(new DerivativeStructure(1, order, 0,
x));
return ds.getPartialDerivative(order);
}
{code}
derivative function
{code}
public static UnivariateFunction derivative(final
UnivariateDifferentiableFunction f, final int order) {
return new UnivariateFunction() {
@Override
public double value(double x) {
DerivativeStructure ds = f.value(new DerivativeStructure(1,
order, 0, x));
return ds.getPartialDerivative(order);
}
};
}
{code}
> Helper methods to FiniteDifferencesDifferentiator
> -------------------------------------------------
>
> Key: MATH-1143
> URL: https://issues.apache.org/jira/browse/MATH-1143
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Alexander Nozik
> Priority: Trivial
>
> A DerivativeStructure and UnivariateDifferentiableFunction are great tools if
> one needs to investigate the whole function but are not convenient if one
> just needs derivative in a given point.
> Perhaps you could add some helper methods to FiniteDifferencesDifferentiator
> or to utility class like FunctionUtils. Also it would be good to have helper
> methods to get the derivatives of UnivariateDifferentiableFunction or
> MultivariateDifferentiableFunction as simple Univariate or Multivariate
> functions (or vector-functions).
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