High-precision computing for Java and JS

Reprinted from: Http://blog.csdn.net/zhutulang/article/details/6844834#commentsJava:

Import Java.math.BigDecimal; /** * Because Java's simple type does not accurately operate on floating-point numbers, this tool class provides fine-grained floating-point arithmetic, including subtraction and rounding.      */public class arith{//default division operation precision private static final int def_div_scale = 10;      This class cannot instantiate private Arith () {}/** * to provide precise addition operations.          * @param v1 summand * @param v2 Addend * @return two parameters and */public static double Add (Double v1,double v2) {          BigDecimal B1 = new BigDecimal (double.tostring (v1));          BigDecimal b2 = new BigDecimal (double.tostring (v2));      Return B1.add (B2). Doublevalue ();      }/** * provides precise subtraction operations.          * @param v1 minuend * @param v2 * @return Two parameter difference */public static double sub (double v1,double v2) {          BigDecimal B1 = new BigDecimal (double.tostring (v1));          BigDecimal b2 = new BigDecimal (double.tostring (v2));      Return B1.subtract (B2). Doublevalue ();      }/** * provides accurate multiplication operations. * @param v1 by multiplier * @param v2 multiplier * @return two parameters of product */public statIC Double Mul (Double v1,double v2) {BigDecimal B1 = new BigDecimal (double.tostring (v1));          BigDecimal b2 = new BigDecimal (double.tostring (v2));      Return b1.multiply (B2). Doublevalue ();      }/** * provides (relative) accurate division operations, when there are no more than an endless case, accurate to * after the decimal point 10 digits, after the number rounded.          * @param v1 Dividend * @param v2 divisor * @return two parameters of quotient */public static double div (Double v1,double v2) {      Return Div (V1,v2,def_div_scale); }/** * provides (relative) accurate division operations.      When the exception occurs, the scale parameter refers to the fixed precision, and the subsequent numbers are rounded.      * @param v1 Dividend * @param v2 divisor * @param scale representation needs to be accurate to several decimal places.              * @return two parameters of quotient */public static double div (double v1,double v2,int scale) {if (scale<0) {          throw new IllegalArgumentException ("The scale must is 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 precise rounding of decimal digits. * @param v The number to be rounded * @param the scale after the decimal point retains several * @return rounded results */public static double round (double V , int scale) {if (scale<0) {throw new IllegalArgumentException ("The scale must          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 ();   }  }

Js:

The Division function, which is used to obtain the exact division result//Description: The JavaScript division result will be error, when the two floating-point number is divided into more obvious.   This function returns a more accurate division result.   Call: Accdiv (ARG1,ARG2)//return value: Arg1 divided by the exact result of arg2 function Accdiv (arg1,arg2) {var t1=0,t2=0,r1,r2; Try{t1=arg1.tostring (). Split (".") [1].length}catch (e) {} try{t2=arg2.tostring (). Split (".") [1].length}catch (e) {} with (Math) {R1=number () (Arg1.tostring (). Replace (".", "")) R2=number (Arg2.tostring (). Replace ("."   , "")) return (R1/R2) *pow (10,T2-T1);   }}//Add a Div method to the number type, which is more convenient to call.   Number.prototype.div = function (ARG) {return Accdiv (this, ARG); }//multiplication function to get the exact multiplication result//description: The result of JavaScript multiplication will be error, it will be more obvious when two floating-point numbers multiply.   This function returns a more accurate multiplication result. Call: Accmul (ARG1,ARG2)//return value: Arg1 times the exact result of arg2 function Accmul (arg1,arg2) {var m=0,s1=arg1.tostring (), S2=arg2.tos   Tring (); Try{m+=s1.split (".") [1].length}catch (e) {} try{m+=s2.split (".") [1].length}catch (e) {} return Number (S1.replace (".", "")) *number (S2.replace (".", ""))/math.pow (10,M)}//   Adding a Mul method to the number type makes it more convenient to call. Number.prototype.mul = FunctiOn (ARG) {return Accmul (ARG, this); }//addition function for accurate addition//description: The addition of JavaScript will have an error, and it will be more obvious when the two floating-point numbers are added.   This function returns a more accurate addition result.   Call: Accadd (ARG1,ARG2)//return value: Arg1 plus arg2 's exact result function Accadd (arg1,arg2) {var r1,r2,m; Try{r1=arg1.tostring (). Split (".") [1].length}catch (e) {r1=0} try{r2=arg2.tostring (). Split (".")    [1].length}catch (e) {r2=0} m=math.pow (10,math.max (R1,R2)) return (arg1*m+arg2*m)/m}//Add an Add method to the number type, which is more convenient to call.   Number.prototype.add = function (ARG) {return accadd (arg,this);   }//include these functions where you want them, and then call it to calculate.        For example you want to calculate: 7*0.8, then change to (7). Mul (8)//Other operations similar, you can get more accurate results.       Subtraction functions function Subtr (ARG1,ARG2) {var r1,r2,m,n; Try{r1=arg1.tostring (). Split (".") [1].length}catch (e) {r1=0} try{r2=arg2.tostring (). Split (".")       [1].length}catch (e) {r2=0} m=math.pow (10,math.max (R1,R2));       Last modify by Deeka//dynamic control accuracy length n= (R1>=R2)? R1:R2;  Return ((arg1*m-arg2*m)/m). ToFixed (n);   }

　　

High-precision computing for Java and JS