Java Code Examples for java.math.BigDecimal#pow()

public static BigDecimal pow(BigDecimal a, BigDecimal b, int scale) {
	if (a.signum() == -1) {
		throw new ArithmeticException("x < 0");
	}
	if (a.equals(BigDecimal.ZERO)) {
		return BigDecimal.ZERO;
	}
	scale = Math.max(Math.max(a.precision(), b.precision()), scale) + 1;
	MathContext mc = new MathContext(scale, RoundingMode.HALF_UP);
	BigDecimal remainer = b.remainder(BigDecimal.ONE, mc);
	if (remainer.equals(BigDecimal.ZERO)) {
		return a.pow(b.intValue(), mc);
	}
	// else we have to do the more expansive route:
	// a^b=exp(b*ln(a)) 
	return exp(b.multiply(ln(a, scale), mc), scale).setScale(scale - 1, RoundingMode.HALF_EVEN);
}
 

public BigDecimal numericExponentiation(BigDecimal first, int second) {
    if (first == null) {
        return null;
    }

    try {
        if (second < 0) {
            return first.pow(second, MATH_CONTEXT);
        } else if (second == 0) {
            return BigDecimal.ONE;
        } else {
            BigDecimal temp = first.pow(-second, MATH_CONTEXT);
            return BigDecimal.ONE.divide(temp, MATH_CONTEXT);
        }
    } catch (Exception e) {
        String message = String.format("numericExponentiation(%s, %s)", first, second);
        logError(message, e);
        return null;
    }
}
 

public void updateResult(int res){
    if( !(res == 1 || res == 0) )
        return;
    this.numSamples++;
    if(res == 1)
        this.dm++;
    if(numSamples > 1){
        BigDecimal p1m_before = new BigDecimal(String.valueOf(1));
        p1m_before = p1m_before.subtract(this.p1);
        p1m_before = p1m_before.pow(this.numSamples-this.dm, MathContext.DECIMAL32);
        this.p1m = this.p1.pow(this.dm, MathContext.DECIMAL32);
        this.p1m = this.p1m.multiply(p1m_before, MathContext.DECIMAL32);

        BigDecimal p0m_before = new BigDecimal(String.valueOf(1));
        p0m_before = p0m_before.subtract(this.p0);
        p0m_before = p0m_before.pow(this.numSamples - this.dm, MathContext.DECIMAL32);

        this.p0m = this.p0.pow(this.dm, MathContext.DECIMAL32);
        this.p0m = this.p0m.multiply(p0m_before, MathContext.DECIMAL32);
    }
}
 

public static String generateUniqueString(int length) {
  int totalChars = alphabet.length;
  BigDecimal exponent = BigDecimal.valueOf(totalChars);
  exponent = exponent.pow(length);
  String code = "";
  BigDecimal number = new BigDecimal(rand.nextInt(1000000));
  BigDecimal num = number.multiply(largePrimeNumber).remainder(exponent);
  code = baseN(num, totalChars);
  int codeLenght = code.length();
  if (codeLenght < length) {
    for (int i = codeLenght; i < length; i++) {
      code = code + alphabet[rand.nextInt(totalChars - 1)];
    }
  }
  if (NumberUtils.isNumber(code.substring(1, 2)) || NumberUtils.isNumber(code.substring(2, 3))) {
    return code;
  } else {
    code = code.substring(0, 1) + alphabet[rand.nextInt(9)] + code.substring(2);
    return code;
  }
}
 

/**
 * Raise to an integer power and round.
 *
 * @param x The base.
 * @param n The exponent.
 * @return x^n.
 */
static public BigDecimal powRound(final BigDecimal x, final int n) {
    /* The relative error in the result is n times the relative error in the input.
     * The estimation is slightly optimistic due to the integer rounding of the logarithm.
     */
    MathContext mc = new MathContext(x.precision() - (int) Math.log10((double) (Math.abs(n))));
    return x.pow(n, mc);
}
 

@TLFunctionAnnotation("Returns the value of the first argument raised to the power of the second argument.")
public static final BigDecimal pow(TLFunctionCallContext context, BigDecimal argument, BigDecimal power) {
	int exponent = power.intValue();
	
	if (exponent < 0) { // CLO-12062: pass MathContext to allow negative exponents
		return argument.pow(exponent, TransformLangExecutor.MAX_PRECISION);
	} else {
    	// MathContext might change precision, use the original implementation for non-negative exponents for backward compatibility
    	return argument.pow(exponent); 
	}
}
 

static Object bigDecimalBinaryOperation(BigDecimal lhs, BigDecimal rhs, int kind)
    throws UtilEvalError
{
    switch(kind)
    {
        // arithmetic
        case PLUS:
            return lhs.add(rhs);

        case MINUS:
            return lhs.subtract(rhs);

        case STAR:
            return lhs.multiply(rhs);

        case SLASH:
            return lhs.divide(rhs);

        case MOD:
        case MODX:
            return lhs.remainder(rhs);

        case POWER:
        case POWERX:
            return lhs.pow(rhs.intValue());

        // can't shift floats
        case LSHIFT:
        case LSHIFTX:
        case RSIGNEDSHIFT:
        case RSIGNEDSHIFTX:
        case RUNSIGNEDSHIFT:
        case RUNSIGNEDSHIFTX:
            throw new UtilEvalError("Can't shift floatingpoint values");

    }
    throw new InterpreterError(
            "Unimplemented binary float operator");
}
 

/**
 * pow(int)
 */
public void testPow() {
    String a = "123121247898748298842980";
    int aScale = 10;
    int exp = 10;
    String c = "8004424019039195734129783677098845174704975003788210729597" +
               "4875206425711159855030832837132149513512555214958035390490" +
               "798520842025826.594316163502809818340013610490541783276343" +
               "6514490899700151256484355936102754469438371850240000000000";
    int cScale = 100;
    BigDecimal aNumber = new BigDecimal(new BigInteger(a), aScale);
    BigDecimal result = aNumber.pow(exp);
    assertEquals("incorrect value", c, result.toString());
    assertEquals("incorrect scale", cScale, result.scale());
}
 

@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
	SpelNodeImpl leftOp = getLeftOperand();
	SpelNodeImpl rightOp = getRightOperand();

	Object leftOperand = leftOp.getValueInternal(state).getValue();
	Object rightOperand = rightOp.getValueInternal(state).getValue();

	if (leftOperand instanceof Number && rightOperand instanceof Number) {
		Number leftNumber = (Number) leftOperand;
		Number rightNumber = (Number) rightOperand;

		if (leftNumber instanceof BigDecimal) {
			BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
			return new TypedValue(leftBigDecimal.pow(rightNumber.intValue()));
		}
		else if (leftNumber instanceof BigInteger) {
			BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
			return new TypedValue(leftBigInteger.pow(rightNumber.intValue()));
		}
		else if (leftNumber instanceof Double || rightNumber instanceof Double) {
			return new TypedValue(Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue()));
		}
		else if (leftNumber instanceof Float || rightNumber instanceof Float) {
			return new TypedValue(Math.pow(leftNumber.floatValue(), rightNumber.floatValue()));
		}

		double d = Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue());
		if (d > Integer.MAX_VALUE || leftNumber instanceof Long || rightNumber instanceof Long) {
			return new TypedValue((long) d);
		}
		else {
			return new TypedValue((int) d);
		}
	}

	return state.operate(Operation.POWER, leftOperand, rightOperand);
}
 

@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
	SpelNodeImpl leftOp = getLeftOperand();
	SpelNodeImpl rightOp = getRightOperand();

	Object leftOperand = leftOp.getValueInternal(state).getValue();
	Object rightOperand = rightOp.getValueInternal(state).getValue();

	if (leftOperand instanceof Number && rightOperand instanceof Number) {
		Number leftNumber = (Number) leftOperand;
		Number rightNumber = (Number) rightOperand;

		if (leftNumber instanceof BigDecimal) {
			BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
			return new TypedValue(leftBigDecimal.pow(rightNumber.intValue()));
		}
		else if (leftNumber instanceof BigInteger) {
			BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
			return new TypedValue(leftBigInteger.pow(rightNumber.intValue()));
		}
		else if (leftNumber instanceof Double || rightNumber instanceof Double) {
			return new TypedValue(Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue()));
		}
		else if (leftNumber instanceof Float || rightNumber instanceof Float) {
			return new TypedValue(Math.pow(leftNumber.floatValue(), rightNumber.floatValue()));
		}

		double d = Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue());
		if (d > Integer.MAX_VALUE || leftNumber instanceof Long || rightNumber instanceof Long) {
			return new TypedValue((long) d);
		}
		else {
			return new TypedValue((int) d);
		}
	}

	return state.operate(Operation.POWER, leftOperand, rightOperand);
}
 

/**
	 * Built-in Java implementation of the pow function for integer exponents between -999999999...999999999.
	 * Only the <code>decPrec</code> leading digits of the output are correct!
	 * @param x
	 * @param n
	 * @return x^n
	 */
	static BigDecimal pow/*Java*/(BigDecimal x, int n, Precision decPrec) {
		// avoid rounding errors
		int innerDecPrec = decPrec.digits() + 4;
//		// avoid ArithmeticException (see comment in class PowTest):
//		if (innerDecPrec==1 && n>9) innerDecPrec = 2;
		// compute result at inner precision
		BigDecimal result = x.pow(n, new MathContext(innerDecPrec, RoundingMode.HALF_EVEN));
		// round to originally wanted output precision
		return decPrec.applyTo(result);
	}
 

@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
	SpelNodeImpl leftOp = getLeftOperand();
	SpelNodeImpl rightOp = getRightOperand();

	Object leftOperand = leftOp.getValueInternal(state).getValue();
	Object rightOperand = rightOp.getValueInternal(state).getValue();

	if (leftOperand instanceof Number && rightOperand instanceof Number) {
		Number leftNumber = (Number) leftOperand;
		Number rightNumber = (Number) rightOperand;

		if (leftNumber instanceof BigDecimal) {
			BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
			return new TypedValue(leftBigDecimal.pow(rightNumber.intValue()));
		}
		else if (leftNumber instanceof BigInteger) {
			BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
			return new TypedValue(leftBigInteger.pow(rightNumber.intValue()));
		}
		else if (leftNumber instanceof Double || rightNumber instanceof Double) {
			return new TypedValue(Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue()));
		}
		else if (leftNumber instanceof Float || rightNumber instanceof Float) {
			return new TypedValue(Math.pow(leftNumber.floatValue(), rightNumber.floatValue()));
		}

		double d = Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue());
		if (d > Integer.MAX_VALUE || leftNumber instanceof Long || rightNumber instanceof Long) {
			return new TypedValue((long) d);
		}
		else {
			return new TypedValue((int) d);
		}
	}

	return state.operate(Operation.POWER, leftOperand, rightOperand);
}
 

/**
 * Private utility method used to compute the square root of a BigDecimal.
 * 
 * @author Luciano Culacciatti 
 * @see <a href="http://www.codeproject.com/Tips/257031/Implementing-SqrtRoot-in-BigDecimal">http://www.codeproject.com/Tips/257031/Implementing-SqrtRoot-in-BigDecimal</a>
 */
private static BigDecimal sqrtNewtonRaphson(final BigDecimal c, final BigDecimal xn, final BigDecimal precision) {
    BigDecimal fx = xn.pow(2).add(c.negate());
    BigDecimal fpx = xn.multiply(new BigDecimal(2));
    BigDecimal xn1 = fx.divide(fpx, 2 * SQRT_DIG.intValue(), RoundingMode.HALF_DOWN);
    xn1 = xn.add(xn1.negate());
    BigDecimal currentSquare = xn1.pow(2);
    BigDecimal currentPrecision = currentSquare.subtract(c);
    currentPrecision = currentPrecision.abs();
    if (currentPrecision.compareTo(precision) <= -1) {
        return xn1;
    }
    return sqrtNewtonRaphson(c, xn1, precision);
}
 

private static BigDecimal piChudnovski(MathContext mathContext) {
	MathContext mc = new MathContext(mathContext.getPrecision() + 10, mathContext.getRoundingMode());

	final BigDecimal value24 = BigDecimal.valueOf(24);
	final BigDecimal value640320 = BigDecimal.valueOf(640320);
	final BigDecimal value13591409 = BigDecimal.valueOf(13591409);
	final BigDecimal value545140134 = BigDecimal.valueOf(545140134);
	final BigDecimal valueDivisor = value640320.pow(3).divide(value24, mc);

	BigDecimal sumA = BigDecimal.ONE;
	BigDecimal sumB = BigDecimal.ZERO;

	BigDecimal a = BigDecimal.ONE;
	long dividendTerm1 = 5; // -(6*k - 5)
	long dividendTerm2 = -1; // 2*k - 1
	long dividendTerm3 = -1; // 6*k - 1
	BigDecimal kPower3 = BigDecimal.ZERO;
	
	long iterationCount = (mc.getPrecision()+13) / 14;
	for (long k = 1; k <= iterationCount; k++) {
		BigDecimal valueK = BigDecimal.valueOf(k);
		dividendTerm1 += -6;
		dividendTerm2 += 2;
		dividendTerm3 += 6;
		BigDecimal dividend = BigDecimal.valueOf(dividendTerm1).multiply(BigDecimal.valueOf(dividendTerm2)).multiply(BigDecimal.valueOf(dividendTerm3));
		kPower3 = valueK.pow(3);
		BigDecimal divisor = kPower3.multiply(valueDivisor, mc);
		a = a.multiply(dividend).divide(divisor, mc);
		BigDecimal b = valueK.multiply(a, mc);
		
		sumA = sumA.add(a);
		sumB = sumB.add(b);
	}
	
	final BigDecimal value426880 = BigDecimal.valueOf(426880);
	final BigDecimal value10005 = BigDecimal.valueOf(10005);
	final BigDecimal factor = value426880.multiply(sqrt(value10005, mc));
	BigDecimal pi = factor.divide(value13591409.multiply(sumA, mc).add(value545140134.multiply(sumB, mc)), mc);

	return round(pi, mathContext);
}
 

public BigDecimal readDecimal64(int scale) throws IOException {
    long i = in.readLong();
    BigDecimal ten = BigDecimal.valueOf(10);
    BigDecimal s = ten.pow(scale);
    return new BigDecimal(i).divide(s);
}
 

private BigInteger removeComma(BigDecimal num, int scale) {
    BigDecimal ten = BigDecimal.valueOf(10);
    BigDecimal s = ten.pow(scale);
    return num.multiply(s).toBigInteger();
}
 

public static BigDecimal square(BigDecimal b1) {
  return b1.pow(2);
}
 

public static BigDecimal getAmountInBytes(Quantity quantity) throws ArithmeticException {
  String value = "";
  if (quantity.getAmount() != null && quantity.getFormat() != null) {
    value = quantity.getAmount() + quantity.getFormat();
  } else if (quantity.getAmount() != null) {
    value = quantity.getAmount();
  }

  if (value == null || value.isEmpty()) {
    throw new IllegalArgumentException("Invalid quantity value passed to parse");
  }
  // Append Extra zeroes if starting with decimal
  if (!Character.isDigit(value.indexOf(0)) && value.startsWith(".")) {
      value = "0" + value;
  }

  Quantity amountFormatPair = parse(value);
  String formatStr = amountFormatPair.getFormat();
  // Handle Decimal exponent case
  if ((formatStr.matches(AT_LEAST_ONE_DIGIT_REGEX)) && formatStr.length() > 1) {
    int exponent = Integer.parseInt(formatStr.substring(1));
    return new BigDecimal("10").pow(exponent, MathContext.DECIMAL64).multiply(new BigDecimal(amountFormatPair.getAmount()));
  }

  BigDecimal digit = new BigDecimal(amountFormatPair.getAmount());
  BigDecimal multiple = new BigDecimal("1");
  BigDecimal binaryFactor = new BigDecimal("2");
  BigDecimal decimalFactor = new BigDecimal("10");

  switch (formatStr) {
    case "Ki":
      multiple = binaryFactor.pow(10, MathContext.DECIMAL64);
      break;
    case "Mi":
      multiple = binaryFactor.pow(20, MathContext.DECIMAL64);
      break;
    case "Gi":
      multiple = binaryFactor.pow(30, MathContext.DECIMAL64);
      break;
    case "Ti":
      multiple = binaryFactor.pow(40, MathContext.DECIMAL64);
      break;
    case "Pi":
      multiple = binaryFactor.pow(50, MathContext.DECIMAL64);
      break;
    case "Ei":
      multiple = binaryFactor.pow(60, MathContext.DECIMAL64);
      break;
    case "n":
      multiple = decimalFactor.pow(-9, MathContext.DECIMAL64);
      break;
    case "u":
      multiple = decimalFactor.pow(-6, MathContext.DECIMAL64);
      break;
    case "m":
      multiple = decimalFactor.pow(-3, MathContext.DECIMAL64);
      break;
    case "k":
      multiple = decimalFactor.pow(3, MathContext.DECIMAL64);
      break;
    case "M":
      multiple = decimalFactor.pow(6, MathContext.DECIMAL64);
      break;
    case "G":
      multiple = decimalFactor.pow(9, MathContext.DECIMAL64);
      break;
    case "T":
      multiple = decimalFactor.pow(12, MathContext.DECIMAL64);
      break;
    case "P":
      multiple = decimalFactor.pow(15, MathContext.DECIMAL64);
      break;
    case "E":
      multiple = decimalFactor.pow(18, MathContext.DECIMAL64);
      break;
  }

  return digit.multiply(multiple);
}
 

/**
 * The <code>power</code> operator.
 * 
 * @param a
 *            a BigDecimal. May not be <code>null</code>.
 * @param exponent
 *            the exponent.
 * @return <code>a.pow(b)</code>
 * @throws NullPointerException
 *             if {@code a} is <code>null</code>.
 */
@Pure
@Inline(value="$1.pow($2)")
public static BigDecimal operator_power(BigDecimal a, int exponent) {
	return a.pow(exponent);
}
 

/**
 * Built-in Java implementation of the pow function for integer exponents between 0...999999999.
 * The result is computed exactly.
 * @param x
 * @param n
 * @return x^n
 */
static BigDecimal nnPowJava(BigDecimal x, int n) {
	return x.pow(n);
}