Example usage for org.apache.commons.math3.dfp DfpField newDfp

Introduction

In this page you can find the example usage for org.apache.commons.math3.dfp DfpField newDfp.

Prototype

public Dfp newDfp(final String s) 

Source Link

Document

Create a Dfp given a String representation.

Usage

From source file:org.orekit.forces.gravity.AssociatedLegendreFunction.java

private Dfp[] getLegendrePolynomial(int n, DfpField dfpField) {

    // get (or create) the list of polynomials for the specified field
    List<Dfp[]> list = LEGENDRE_POLYNOMIALS.get(dfpField.getRadixDigits());
    if (list == null) {
        list = new ArrayList<Dfp[]>();
        list.add(new Dfp[] { dfpField.getOne() // P0(X) = 1
        });//w ww  . j a v a2 s.  c o m
        list.add(new Dfp[] { dfpField.getZero(), dfpField.getOne() // P1(X) = 0 + 1 * X
        });
    }

    while (list.size() <= n) {

        // build polynomial Pk+1 using recursion formula
        // (k+1) P<sub>k+1</sub>(X) = (2k+1) X P<sub>k</sub>(X) - k P<sub>k-1</sub>(X)
        int k = list.size() - 1;
        Dfp kDfp = dfpField.newDfp(k);
        Dfp kP1Dfp = kDfp.add(dfpField.getOne());
        Dfp ckDfp = kP1Dfp.add(kDfp).divide(kP1Dfp);
        Dfp[] pk = list.get(k);
        Dfp ckM1Dfp = kDfp.divide(kP1Dfp).negate();
        Dfp[] pkM1 = list.get(k - 1);

        Dfp[] pkP1 = new Dfp[k + 2];
        pkP1[0] = ckM1Dfp.multiply(pkM1[0]);
        for (int i = 0; i < k; ++i) {
            if ((k - i) % 2 == 1) {
                pkP1[i + 1] = dfpField.getZero();
            } else {
                pkP1[i + 1] = ckDfp.multiply(pk[i]).add(ckM1Dfp.multiply(pkM1[i + 1]));
            }
        }
        pkP1[k + 1] = ckDfp.multiply(pk[k]);

        list.add(pkP1);

    }

    // retrieve degree n polynomial
    return list.get(n);

}

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From source file:org.orekit.forces.gravity.AssociatedLegendreFunction.java

private Dfp[] differentiateLegendrePolynomial(Dfp[] p, int m, DfpField dfpField) {
    Dfp[] dp = new Dfp[p.length - m];
    for (int i = 0; i < dp.length; ++i) {
        dp[i] = p[i + m];/*from www  .jav  a  2s .c  o  m*/
        for (int j = m; j > 0; --j) {
            dp[i] = dp[i].multiply(dfpField.newDfp(i + j));
        }
    }
    return dp;
}

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From source file:org.orekit.forces.gravity.AssociatedLegendreFunction.java

public AssociatedLegendreFunction(boolean normalized, int n, int m, DfpField dfpField) {

    this.m = m;/*w  ww.  jav a  2s  .  c o m*/

    // store mth derivative of the degree n Legendre polynomial
    polynomial = differentiateLegendrePolynomial(getLegendrePolynomial(n, dfpField), m, dfpField);

    if (normalized) {
        // compute normalization coefficient
        Dfp c = dfpField.newDfp(((m == 0) ? 1.0 : 2.0) * (2 * n + 1));
        for (int k = 0; k < m; ++k) {
            c = c.divide(dfpField.newDfp((n + 1 + k) * (n - k)));
        }
        this.normalization = c.sqrt();
    } else {
        this.normalization = dfpField.getOne();
    }

}

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From source file:org.rhwlab.BHC.GammaTest.java

static public void main(String[] args) {
    int n = 1000;
    DfpField field = new DfpField(20);
    for (int i = 0; i < n; ++i) {
        Dfp G = field.newDfp(Gamma.logGamma(i)).exp();
        System.out.printf("%d: %e %e %s\n", i, Gamma.gamma(i), Gamma.logGamma(i), G.toString());
    }//from  w w w. j av  a2s  .  c  o m
}

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