How to get derivatives using apache lib

Question

I am using apache library to compute derivates. what I want to do is to get the derivates of the following equation

2+(2*x^2)+(3*x)+5

I followed the below posted code but I am a bit confused regarding the parameters stated below. Please help me to find out how to get the derivatives of the above equation.

code:

int params = 1;
int order = 2;
double xRealValue = 5;
DerivativeStructure x = new DerivativeStructure(params, order, 0,  
    xRealValue);
DerivativeStructure y = x.pow(2);                    //COMPILE ERROR
Log.i(TAG, "y = " + y.getValue());
Log.i(TAG, "y = " + y.getPartialDerivative(1));
Log.i(TAG, "y = " + y.getPartialDerivative(2));

Answer 1

commons-math3 version 3.6 does not give any compilation error, and your code works.

import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;

your equation can be written as below

int xValue = 5;

int howManyUnknowParamsHasFunction = 1;
int howManyDeriviationWillYouTake = 2;
int whatIsTheIndexOfThisParameterX = 0;

DerivativeStructure x = new DerivativeStructure(howManyUnknowParamsHasFunction, howManyDeriviationWillYouTake, whatIsTheIndexOfThisParameterX, xValue);

// x --> x^2.
DerivativeStructure x2 = x.pow(2);

//y = 2x^2 + 3x + 7
DerivativeStructure y = new DerivativeStructure(2.0, x2, 3.0, x).add(7);