Java accurate calculation Method __ algorithm

/**  * because Java's simple type does not accurately operate on floating-point numbers, this tool class provides accurate floating-point operations, including subtraction and rounding.

 */package com.bwsk.common.utils;

Import Java.math.BigDecimal;
 /** * Because Java's simple type does not accurately operate on floating-point numbers, this tool class provides precise floating-point operations, including subtraction and rounding.

	*/public class Arithutil {//default division precision private static final int def_div_scale = 10;
	 This class cannot instantiate private Arithutil () {}/** * provides exact addition operations. * * @param v1 * summand * @param v2 * addends * @return two parameters and/or public static double add (Dou
		BLE v1, double v2) {BigDecimal B1 = new BigDecimal (double.tostring (v1));
		BigDecimal b2 = new BigDecimal (double.tostring (v2));
	Return B1.add (B2). Doublevalue ();
	 /** * Provides an accurate subtraction operation. * * @param v1 * Bing * @param v2 * * @return two parameters of the difference * * public static double sub (dou
		BLE v1, double v2) {BigDecimal B1 = new BigDecimal (double.tostring (v1));
		BigDecimal b2 = new BigDecimal (double.tostring (v2));
	Return B1.subtract (B2). Doublevalue ();
	 /** * Provides an accurate multiplication operation. * * @parAM V1 * Multiplier * @param v2 * multiplier * @return two parameters of product/public static double Mul (double v1, dou
		BLE v2) {BigDecimal B1 = new BigDecimal (double.tostring));
		BigDecimal b2 = new BigDecimal (double.tostring (v2));
	Return b1.multiply (B2). Doublevalue ();
	 /** * provides (relative) accurate division operations, which, when in addition to the circumstances, are accurate to 10 digits after the decimal point, after which the numbers are rounded. * * @param v1 * Dividend * @param v2 * divisor * @return Two parameters of the merchant/public static double div (dou
	BLE v1, double v2) {return div (v1, v2, Def_div_scale); /** * provides (relative) precise division operations.
	 When an exception occurs, the precision is specified by the scale parameter, and subsequent digits are rounded.
	 * @param v1 * Dividend * @param v2 * @param scale * Indicates the need to be accurate to several decimal places. * @return Two-parameter merchant/public static double div (double v1, double v2, int scale) {if (Scale < 0) {throw new Ill
		Egalargumentexception ("The scale must be a positive integer or zero");
		} BigDecimal B1 = new BigDecimal (double.tostring (v1)); BigDecimal B2 = New BigDecimal (double.tostring (v2));
	Return B1.divide (B2, scale, bigdecimal.round_half_up). Doublevalue ();
	 /** * Provides accurate decimal rounding processing. * * @param v * need to rounded the number * @param scale * After the decimal point to retain a few * @return rounded results * * public Stati C Double round (double v, int scale) {if (Scale < 0) {throw new IllegalArgumentException ("The scale Mus
		t be a positive integer or zero ");
		} BigDecimal B = new BigDecimal (double.tostring (v));
		BigDecimal one = new BigDecimal ("1");
	Return B.divide (one, scale, bigdecimal.round_half_up). Doublevalue (); /** * @param str1 * Operand 1 * @param str2 * Operands 2 * The result of multiplying the number represented by the two strings * * * public s Tatic double mulstrtodouble (String str1, String str2) {return arithutil. Mul (double.parsedouble), str1
	Double (STR2)); /** * @param str1 * Operand 1 * @param str2 * operation number 2 * @return Two string The result of the addition of the number is * * Public s Tatic Double AddStrtodouble (String str1, String str2) {return arithutil. Add (Double.parsedouble (STR1), double.parsedouble (STR2)); /** * @param str1 * Operand 1 * @param str2 * Operand 2 * @return The result of a number subtracted from two strings * * Public s Tatic double substrtodouble (String str1, String str2) {return arithutil. Sub (double.parsedouble (str1), Double.Parse
	Double (STR2)); 
	 /** * @param str1 * Operand 1 * @param str2 * Operands 2 * @param count * Keep several decimal rounded
		* Multiplies the number represented by two strings and preserves the result of the Count bit decimal * * public static double mulstrtodouble (string str1, String str2, int count) {
	Return Arithutil.round (Arithutil.mul (double.parsedouble (STR1), double.parsedouble (STR2)), count); /** * Method Description: Determine whether two double is equal input parameters: * * @param d1 * @param d2 * @return return Parameters: Boolean finish date: June 29, 2015 6:45:
		33 Version: v 1.0 */public static Boolean equaldouble (double D1, double D2) {BigDecimal bd1 = new BigDecimal (D1); BigDecimal Bd2 = new BIgdecimal (D2);
	Return Bd1.compareto (bd2) = = 0;  /** * Method Description: Determine whether two D1 is greater than D2 input parameter: * * @param d1 * @param d2 * @return return Parameters: Boolean finish date: June 29, 2015 6:45:33
		Version: v 1.0 */public static Boolean greatterdouble (double D1, double D2) {BigDecimal bd1 = new BigDecimal (D1);
		BigDecimal bd2 = new BigDecimal (D2);
	Return Bd1.compareto (BD2) > 0;  /** * Method Description: Determine whether two D1 is less than D2 input parameter: * * @param d1 * @param d2 * @return return Parameters: Boolean finish date: June 29, 2015 6:45:33
		Version: v 1.0 */public static Boolean lighterdouble (double D1, double D2) {BigDecimal bd1 = new BigDecimal (D1);
		BigDecimal bd2 = new BigDecimal (D2);
	Return Bd1.compareto (BD2) < 0;  /** * Addition Operation (EAST) * * @param A * @param b * @return/public static BigDecimal Add (BigDecimal A, BigDecimal
	b) {return a.add (b);
	/** * Take absolute value (east) * @param A * @return/public static BigDecimal abs (BigDecimal a) {return a.abs ();
 }
}