Exemplo n.º 1
0
        public BigInteger gcd(BigInteger val)
        {
            BigInteger val1 = this.abs();
            BigInteger val2 = val.abs();

            // To avoid a possible division by zero
            if (val1.signum() == 0)
            {
                return(val2);
            }
            else if (val2.signum() == 0)
            {
                return(val1);
            }

            // Optimization for small operands
            // (op2.bitLength() < 64) and (op1.bitLength() < 64)
            if (((val1.numberLength == 1) || ((val1.numberLength == 2) && (val1.digits[1] > 0))) &&
                (val2.numberLength == 1 || (val2.numberLength == 2 && val2.digits[1] > 0)))
            {
                return(BigInteger.valueOf(Division.gcdBinary(val1.longValue(), val2
                                                             .longValue())));
            }

            return(Division.gcdBinary(val1.copy(), val2.copy()));
        }
Exemplo n.º 2
0
        /** @see BigInteger#doubleValue() */
        internal static double bigInteger2Double(BigInteger val)
        {
            // val.bitLength() < 64
            if ((val.numberLength < 2)
                || ((val.numberLength == 2) && (val.digits[1] > 0))) {
                return val.longValue();
            }
            // val.bitLength() >= 33 * 32 > 1024
            if (val.numberLength > 32) {
                return ((val.sign > 0) ? double.PositiveInfinity
                        : double.NegativeInfinity);
            }

            return Convert.ToDouble(val.ToString());
        }
Exemplo n.º 3
0
        /** @see BigInteger#doubleValue() */
        internal static double bigInteger2Double(BigInteger val)
        {
            // val.bitLength() < 64
            if ((val.numberLength < 2) ||
                ((val.numberLength == 2) && (val.digits[1] > 0)))
            {
                return(val.longValue());
            }
            // val.bitLength() >= 33 * 32 > 1024
            if (val.numberLength > 32)
            {
                return((val.sign > 0) ? double.PositiveInfinity
                        : double.NegativeInfinity);
            }

            return(Convert.ToDouble(val.ToString()));
        }
Exemplo n.º 4
0
Arquivo: Division.cs Projeto: vic/ioke
        internal static BigInteger gcdBinary(BigInteger op1, BigInteger op2)
        {
            // PRE: (op1 > 0) and (op2 > 0)

            /*
             * Divide both number the maximal possible times by 2 without rounding
             * gcd(2*a, 2*b) = 2 * gcd(a,b)
             */
            int lsb1 = op1.getLowestSetBit();
            int lsb2 = op2.getLowestSetBit();
            int pow2Count = Math.Min(lsb1, lsb2);

            BitLevel.inplaceShiftRight(op1, lsb1);
            BitLevel.inplaceShiftRight(op2, lsb2);

            BigInteger swap;
            // I want op2 > op1
            if (op1.compareTo(op2) == BigInteger.GREATER) {
                swap = op1;
                op1 = op2;
                op2 = swap;
            }

            do { // INV: op2 >= op1 && both are odd unless op1 = 0

                // Optimization for small operands
                // (op2.bitLength() < 64) implies by INV (op1.bitLength() < 64)
                if (( op2.numberLength == 1 )
                    || ( ( op2.numberLength == 2 ) && ( op2.digits[1] > 0 ) )) {
                    op2 = BigInteger.valueOf(Division.gcdBinary(op1.longValue(),
                                                                op2.longValue()));
                    break;
                }

                // Implements one step of the Euclidean algorithm
                // To reduce one operand if it's much smaller than the other one
                if (op2.numberLength > op1.numberLength * 1.2) {
                    op2 = op2.remainder(op1);
                    if (op2.signum() != 0) {
                        BitLevel.inplaceShiftRight(op2, op2.getLowestSetBit());
                    }
                } else {

                    // Use Knuth's algorithm of successive subtract and shifting
                    do {
                        Elementary.inplaceSubtract(op2, op1); // both are odd
                        BitLevel.inplaceShiftRight(op2, op2.getLowestSetBit()); // op2 is even
                    } while (op2.compareTo(op1) >= BigInteger.EQUALS);
                }
                // now op1 >= op2
                swap = op2;
                op2 = op1;
                op1 = swap;
            } while (op1.sign != 0);
            return op2.shiftLeft(pow2Count);
        }
Exemplo n.º 5
0
        internal static BigInteger gcdBinary(BigInteger op1, BigInteger op2)
        {
            // PRE: (op1 > 0) and (op2 > 0)

            /*
             * Divide both number the maximal possible times by 2 without rounding
             * gcd(2*a, 2*b) = 2 * gcd(a,b)
             */
            int lsb1      = op1.getLowestSetBit();
            int lsb2      = op2.getLowestSetBit();
            int pow2Count = Math.Min(lsb1, lsb2);

            BitLevel.inplaceShiftRight(op1, lsb1);
            BitLevel.inplaceShiftRight(op2, lsb2);

            BigInteger swap;

            // I want op2 > op1
            if (op1.compareTo(op2) == BigInteger.GREATER)
            {
                swap = op1;
                op1  = op2;
                op2  = swap;
            }

            do   // INV: op2 >= op1 && both are odd unless op1 = 0

            // Optimization for small operands
            // (op2.bitLength() < 64) implies by INV (op1.bitLength() < 64)
            {
                if ((op2.numberLength == 1) ||
                    ((op2.numberLength == 2) && (op2.digits[1] > 0)))
                {
                    op2 = BigInteger.valueOf(Division.gcdBinary(op1.longValue(),
                                                                op2.longValue()));
                    break;
                }

                // Implements one step of the Euclidean algorithm
                // To reduce one operand if it's much smaller than the other one
                if (op2.numberLength > op1.numberLength * 1.2)
                {
                    op2 = op2.remainder(op1);
                    if (op2.signum() != 0)
                    {
                        BitLevel.inplaceShiftRight(op2, op2.getLowestSetBit());
                    }
                }
                else
                {
                    // Use Knuth's algorithm of successive subtract and shifting
                    do
                    {
                        Elementary.inplaceSubtract(op2, op1);                   // both are odd
                        BitLevel.inplaceShiftRight(op2, op2.getLowestSetBit()); // op2 is even
                    } while (op2.compareTo(op1) >= BigInteger.EQUALS);
                }
                // now op1 >= op2
                swap = op2;
                op2  = op1;
                op1  = swap;
            } while (op1.sign != 0);
            return(op2.shiftLeft(pow2Count));
        }
Exemplo n.º 6
0
 private void setUnscaledValue(BigInteger unscaledValue)
 {
     this.intVal = unscaledValue;
     this._bitLength = unscaledValue.bitLength();
     if(this._bitLength < 64) {
         this.smallValue = unscaledValue.longValue();
     }
 }
Exemplo n.º 7
0
        private static BigDecimal divideBigIntegers(BigInteger scaledDividend, BigInteger scaledDivisor, int scale, RoundingMode roundingMode)
        {
            BigInteger[] quotAndRem = scaledDividend.divideAndRemainder(scaledDivisor);  // quotient and remainder

            // If after division there is a remainder...
            BigInteger quotient = quotAndRem[0];
            BigInteger remainder = quotAndRem[1];
            if (remainder.signum() == 0) {
                return new BigDecimal(quotient, scale);
            }
            int sign = scaledDividend.signum() * scaledDivisor.signum();
            int compRem;                                      // 'compare to remainder'
            if(scaledDivisor.bitLength() < 63) { // 63 in order to avoid out of long after <<1
                long rem = remainder.longValue();
                long divisor = scaledDivisor.longValue();
                compRem = longCompareTo(Math.Abs(rem) << 1,Math.Abs(divisor));
                // To look if there is a carry
                compRem = roundingBehavior(quotient.testBit(0) ? 1 : 0,
                                           sign * (5 + compRem), roundingMode);

            } else {
                // Checking if:  remainder * 2 >= scaledDivisor
                compRem = remainder.abs().shiftLeftOneBit().compareTo(scaledDivisor.abs());
                compRem = roundingBehavior(quotient.testBit(0) ? 1 : 0,
                                           sign * (5 + compRem), roundingMode);
            }
            if (compRem != 0) {
                if(quotient.bitLength() < 63) {
                    return valueOf(quotient.longValue() + compRem,scale);
                }
                quotient = quotient.add(BigInteger.valueOf(compRem));
                return new BigDecimal(quotient, scale);
            }
            // Constructing the result with the appropriate unscaled value
            return new BigDecimal(quotient, scale);
        }