Examples with OpenIntToDoubleHashMap org.hipparchus.util.OpenIntToDoubleHashMap used on opensource projects

Example 1 with OpenIntToDoubleHashMap

use of org.hipparchus.util.OpenIntToDoubleHashMap in project symja_android_library by axkr.

the class Expr2Object method toPolynomial.

public static double[] toPolynomial(IExpr expr, ISymbol sym) {
    OpenIntToDoubleHashMap map = toPolynomialMap(expr, sym);
    if (map == null) {
        return null;
    }
    int max = 5;
    int k;
    for (OpenIntToDoubleHashMap.Iterator iterator = map.iterator(); iterator.hasNext(); ) {
        iterator.advance();
        k = iterator.key();
        if (k > max) {
            max = k;
        }
    }
    double[] array = new double[max + 1];
    for (OpenIntToDoubleHashMap.Iterator iterator = map.iterator(); iterator.hasNext(); ) {
        iterator.advance();
        k = iterator.key();
        // if (k <= 4) {
        array[k] = iterator.value();
    // } else {
    // return null;
    // }
    }
    int n = array.length;
    while ((n > 1) && (array[n - 1] == 0.0)) {
        --n;
    }
    if (n < array.length) {
        double[] coefficients = new double[n];
        System.arraycopy(array, 0, coefficients, 0, n);
        return coefficients;
    }
    return array;
}

Example 2 with OpenIntToDoubleHashMap

use of org.hipparchus.util.OpenIntToDoubleHashMap in project symja_android_library by axkr.

the class Expr2Object method toPolynomialMap.

/**
	 * 
	 * @param expr
	 * @param sym
	 * @return <code>null</code> if the expression couldn't be converted to a
	 *         polynomial.
	 */
public static OpenIntToDoubleHashMap toPolynomialMap(IExpr expr, ISymbol sym) {
    try {
        OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
        if (expr.isPlus()) {
            IAST plus = (IAST) expr;
            for (int i = 1; i < plus.size(); i++) {
                if (plus.get(i).isTimes()) {
                    IAST times = (IAST) plus.get(i);
                    double coeff = 0;
                    int exp = -1;
                    for (int j = 1; j < times.size(); j++) {
                        if (times.get(j).isPower()) {
                            IAST power = (IAST) times.get(j);
                            if (power.arg1().equals(sym)) {
                                if (exp != (-1)) {
                                    return null;
                                }
                                IExpr res = F.evaln(power.arg2());
                                if (!(res instanceof INum)) {
                                    return null;
                                }
                                exp = DoubleMath.roundToInt(((INum) res).doubleValue(), RoundingMode.UNNECESSARY);
                                if (exp < 0) {
                                    return null;
                                }
                                continue;
                            }
                        } else if (times.get(j).isSymbol()) {
                            if (times.get(j).equals(sym)) {
                                if (exp != (-1)) {
                                    return null;
                                }
                                exp = 1;
                                continue;
                            }
                        }
                        if (times.get(j) instanceof INum) {
                            coeff += ((INum) times.get(j)).doubleValue();
                            continue;
                        }
                        IExpr res = F.evaln(times.get(j));
                        if (!(res instanceof INum)) {
                            return null;
                        }
                        coeff += ((INum) res).doubleValue();
                    }
                    if (exp == (-1)) {
                        exp = 0;
                    }
                    addCoefficient(map, coeff, exp);
                    continue;
                } else if (plus.get(i).isPower()) {
                    IAST power = (IAST) plus.get(i);
                    if (power.arg1().equals(sym)) {
                        IExpr res = F.evaln(power.arg2());
                        if (!(res instanceof INum)) {
                            return null;
                        }
                        int exp = DoubleMath.roundToInt(((INum) res).doubleValue(), RoundingMode.UNNECESSARY);
                        if (exp < 0) {
                            return null;
                        }
                        addCoefficient(map, 1.0, exp);
                        continue;
                    }
                    return null;
                } else if (plus.get(i).isSymbol()) {
                    if (plus.equalsAt(i, sym)) {
                        addCoefficient(map, 1.0, 1);
                        continue;
                    }
                    return null;
                }
                if (plus.get(i) instanceof INum) {
                    addCoefficient(map, ((INum) plus.get(i)).doubleValue(), 0);
                    continue;
                }
                IExpr res = F.evaln(plus.get(i));
                if (!(res instanceof INum)) {
                    return null;
                }
                addCoefficient(map, ((INum) res).doubleValue(), 0);
            }
            return map;
        }
    } catch (Exception ex) {
    }
    return null;
}