* By default, the value for deviation is set to 0.0000000001. However, the deviation value can be set t0 0.
* Computations are executed as described above, if the PRECISE flag is set to true (default = false). * If PRECISE = false, two values stored in other fields, namely DEVIATION_DOUBLE and DEVIATION_DOUBLE_MINUS are used. * These are double values which are used the same way as the deviation value above, but the computation is much faster. All critical computations * are executed as computations on doubles, then.
* There is only one double (numerator) field inside of this class which stores the Rational. The denominator is supposed to be 1 always. */ public class RationalDouble extends Rational implements Serializable{ /* * members */ static RationalDouble deviation = new RationalDouble(0.0000000001); //allowed deviation for comparisons to be equal; nine 0s static double DEVIATION_DOUBLE = 0.000001; //seven 0s static double DEVIATION_DOUBLE_NEG = -0.000001; //seven 0s static boolean PRECISE = false; private double d; //numerator /* * constructors */ /** * Constructs a new Rational from n. * * @param n the numerator */ public RationalDouble(int n) { this.d = (double)n; } /** * Constructs a new Rational from f. * * @param f the numerator */ public RationalDouble(double f) { this.d = f; } /** * Constructs a new Rational from r. * * @param r the numerator */ public RationalDouble(Rational r) { this.d = ((RationalDouble)r).d; } /** * Constructs a new Rational from numerator and denominator. * The numerator is set to num/den * @param num the numerator * @param den the denominator */ public RationalDouble(int num, int den) { this.d = ((double)num/den); } /* * methods */ /** * Returns the numerator of the Rational. * * @return the numerator as int */ public int getNumerator() { int dLength = String.valueOf((int)d).length(); int multiple = 0; if (dLength < 9) { multiple = 9-dLength; return (int)(d*Math.pow(10,multiple)); }//if else return (int)d; }//end method getNumerator /** * Returns the denominator of the Rational. * * @return the denominator as int */ public int getDenominator() { int dLength = String.valueOf((int)d).length(); int multiple = 0; if (dLength < 9) { multiple = 9-dLength; return (int)(Math.pow(10,multiple)); }//if else return 1; }//end method getDenominator /** * Sets this to r. * * @param r the new Rational value r */ public void assign (Rational r) { this.d = ((RationalDouble)r).d; } /** * Sets this to i. * * @param i the new Rational value i */ public void assign (int i) { this.d = i; } /** * Sets this to d. * * @param d the new Rational value d */ public void assign (double d) { this.d = d; } /** * Returns this * r. * * @param r the second factor * @return product of this and r */ public Rational times (Rational r) { return new RationalDouble(this.d * ((RationalDouble)r).d); } /** * Returns this * i. * * @param i the second factor */ public Rational times (int i) { return new RationalDouble(this.d * i); } /** * Returns this * r. * Stores the result in in. * * @param r the second factor * @param in the result is stored in this variable * @return this * r */ public Rational times (Rational r, Rational in) { ((RationalDouble)in).d = (this.d * ((RationalDouble)r).d); return in; }//end method times /** * Returns this : r. * * @param r the divisor * @return this : r */ public Rational dividedby (Rational r) { return new RationalDouble(this.d / ((RationalDouble)r).d); } /** * Returns this : i. * * @param i the divisor * @return this : i */ public Rational dividedby (int i) { return new RationalDouble(this.d / i); } /** * Returns this : r. * The result is stored in in. * * @param r the divisor * @param in the result is stored in this variable * @return this : r */ public Rational dividedby (Rational r, Rational in) { ((RationalDouble)in).d = (this.d / ((RationalDouble)r).d); return in; } /** * Returns this + r. * * @param r the summand * @return this + r */ public Rational plus (Rational r) { return new RationalDouble(this.d + ((RationalDouble)r).d); } /** * Returns this + i. * * @param i the summand * @return this + i */ public Rational plus (int i) { return new RationalDouble(this.d + i); } /** * Returns this + r. * The result is stored in in. * * @param r the summand * @param in the result is stored in this variable * @return this + r */ public Rational plus (Rational r, Rational in) { ((RationalDouble)in).d = (this.d + ((RationalDouble)r).d); return in; }//end method plus /** * Returns this - r. * * @param r the minuend * @return this - r */ public Rational minus (Rational r) { return new RationalDouble(this.d - ((RationalDouble)r).d); } /** * Returns this - i. * * @param i the minuend * @return this - i */ public Rational minus (int i) { return new RationalDouble(this.d - i); } /** * Returns this - r. * The result is stored in the variable in. * * @param r the minuend * @param in the result is stored in this variable * @return this - r */ public Rational minus (Rational r, Rational in) { ((RationalDouble)in).d = (this.d - ((RationalDouble)r).d); return in; }//end method minus /** * Returns true, if this is less than r. * * @param r the Rational to compare with * @return true, if this < r */ public boolean less (Rational r) { if (PRECISE) { if (this.equal(r)) return false; else return (this.d < ((RationalDouble)r).d); }//if else { if ((this.d - ((RationalDouble)r).d < DEVIATION_DOUBLE) && (this.d - ((RationalDouble)r).d > DEVIATION_DOUBLE_NEG)) return false; else return (this.d < ((RationalDouble)r).d); }//else }//end method less /** * Returns true, if this is less than i. * * @param i the int to compare with * @return true, if this < i */ public boolean less (int i) { if (PRECISE) { if (this.equal(i)) return false; return (this.d < i); }//if else { if ((this.d - i < DEVIATION_DOUBLE) && (this.d - i > DEVIATION_DOUBLE_NEG)) return false; else return (this.d < i); }//else }//end method less /** * Returns true, if this is equal to r. * * @param r the Rational to compare with * @return true, if this = r */ public boolean equal (Rational r) { if (PRECISE) { double erg = Math.abs(this.d - ((RationalDouble)r).d); if (erg < deviation.d) return true; else return false; }//if else { if ((this.d - ((RationalDouble)r).d < DEVIATION_DOUBLE) && (this.d - ((RationalDouble)r).d > DEVIATION_DOUBLE_NEG)) return true; else return false; }//else }//end method equal /** * Returns true, if this is equal to i. * * @param i the int to compare with * @return true, if this = i */ public boolean equal (int i) { if (PRECISE) { double erg = Math.abs(this.d - i); if (erg < deviation.d) return true; else return false; }//if else { if ((this.d - i < DEVIATION_DOUBLE) && (this.d - i > DEVIATION_DOUBLE_NEG)) return true; else return false; }//else }//end method equal /** * Returns true, if this is greater than r. * * @param r the Rational to compare with * @return true, if this > r */ public boolean greater (Rational r) { if (PRECISE) { if (this.equal(r)) return false; else return (this.d > ((RationalDouble)r).d); }//if else { if ((this.d - ((RationalDouble)r).d < DEVIATION_DOUBLE) && (this.d - ((RationalDouble)r).d > DEVIATION_DOUBLE_NEG)) return false; else return (this.d > ((RationalDouble)r).d); }//else }//end method greater /** * Returns true, if this is greater than i. * * @param i the int to compare with * @return true, if this > i */ public boolean greater (int i) { if (PRECISE) { if (this.equal(i)) return false; return (this.d > i); }//if else { if ((this.d - i < DEVIATION_DOUBLE) && (this.d - i > DEVIATION_DOUBLE_NEG)) return false; else return (this.d > i); }//else }//end method greater /** * Compares this and r and returns one of {0, 1, -1}.
* Returns 0, if this = r
* Returns -1, if this < r
* Returns 1 otherwise * * @param r the Rational to compare with * @return one of {0, 1, -1} as byte */ public byte comp (Rational r) { //System.out.println("RD.comp: dev: "+DEVIATION_DOUBLE+", this.d: "+this.d+", r.d: "+((RationalDouble)r).d); if (this.equal(r)) return 0; //if (this.d < ((RationalDouble)r).d) return -1; if (this.less(r)) return -1; else return 1; }//end method comp /** * Returns true, if this <= r. * * @param r the Rational to compare with * @return true if this <= r */ public boolean lessOrEqual (Rational r) { if (PRECISE) return (this.equal(r) || this.less(r)); else if (this.d - ((RationalDouble)r).d < DEVIATION_DOUBLE) return true; return false; }//end method lessOrEqual /** * Returns true, if this >= r. * * @param r the Rational to compare with * @return true if this >= r */ public boolean greaterOrEqual (Rational r) { if (PRECISE) return (this.equal(r) || this.greater(r)); else if (this.d - ((RationalDouble)r).d >= DEVIATION_DOUBLE_NEG) return true; return false; }//end method greaterOrEqual /** * Returns this as int. * * @return this as int */ public int getInt() { return (int)this.d; } /** * Returns this as double. * * @return this as double */ public double getDouble() { return this.d; } /** * Converts this to a String. * * @return this as String */ public String toString() { return String.valueOf(this.d); } /** * Returns a copy of this. * * @return the copy */ public Rational copy() {return new RationalDouble(this); } /** * Returns the absolute value of this. * * @return |this| */ public Rational abs() { if (this.d < 0) this.d = this.d * (-1); return this; }//end method abs /** * Rounds this to i digits. * * @param digits the number of digits * @throws WrongDigitValueException if 0 > digits > 9 */ public void round (int digits) throws WrongDigitValueException { if (digits<0 || digits>9) throw new WrongDigitValueException("RationalDouble: Wrong value for digits. Must lie in range (0..9)!"); int times = (int)Math.pow(10,digits); double temp = Math.round(this.d * times); this.d = temp/times; }//end method round /** * Sets an field of the class to b. * The implementor can decide, whether the class should have a 'precise' and a 'less precise' implementation. By using this method * a flag can be set to use the more or less precise version. PRECISE == true means, that the deviation value is automatically set to 0. * * @param precise PRECISE is set to this value */ public void setPrecision (Boolean precise) { PRECISE = precise.booleanValue(); }//end method setPrecision /** * Returns the deviation value for computations with deviation = true. * * @return the deviation value */ public Rational getDeviation() { return this.deviation; }//end method getDeviation /** * Sets the deviation value deviation. * This number is used for equality checks when PRECISE = true. * * @param r the new deviation value */ public void setDeviation(Rational r) { this.deviation = (RationalDouble)r; }//end method setDeviation /** * Sets the deviation values DEVIATION_DOUBLE and DEVIATION_DOUBLE_NEG. * This value is used for PRECISE = false. * DEVIATION_DOUBLE is set to d and DEVIATION_DOUBLE_NEG is set to -d. * * @param d the new deviation value */ public void setDeviationDouble(Double d) { this.DEVIATION_DOUBLE = d.doubleValue(); this.DEVIATION_DOUBLE_NEG = -1*d.doubleValue(); }//end method setDeviationDouble /** * Returns the DEVIATION_DOUBLE value. * * @return the deviation value */ public double getDeviationDouble() { return this.DEVIATION_DOUBLE; }//end method getDeviationDouble /** * Returns the DEVIATION_DOUBLE_NEG value. * * @return the deviation value. */ public double getDeviationDoubleNeg() { return this.DEVIATION_DOUBLE_NEG; }//end method getDeviationDoubleNeg }//end class RationalDouble