Is there a fixed-point library for actionscript 3?

问题

I would like to code a calculator in Flex but can't find any fixed-point libraries on the web.

For the calculator, I need more precision then IEEE 754 can guarantee. For example:

trace(1.4 - .4); //should be 1 but it is 0.9999999999999999

Can someone suggest a good fixed-point library please ?

Thank you in advance

回答1:

It works but it is not perfect, all credits go to Josh from http://joshblog.net/2007/01/30/flash-floating-point-number-errors/

/**
 * Corrects errors caused by floating point math.
 */
public function correctFloatingPointError(number:Number, precision:int = 5):Number
{
    //default returns (10000 * number) / 10000
    //should correct very small floating point errors
    var correction:Number = Math.pow(10, precision);
    return Math.round(correction * number) / correction;
}
/**
 * Tests if two numbers are <em>almost</em> equal.
 */
public function fuzzyEquals(number1:Number, number2:Number, precision:int = 5):Boolean
{
    var difference:Number = number1 - number2;
    var range:Number = Math.pow(10, -precision);
    //default check:
    //0.00001 <difference> -0.00001
    return difference <range && difference> -range;
}
/*
Copyright (c) 2007 Josh Tynjala
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
*/

Thank you again :)

回答2:

I am not aware of any but in the meantime you can use this snippet of code (not mine):

    public static function correctFloatingPointError(number:Number, precision:int = 5):Number
    {
        //default returns (10000 * number) / 10000
        //should correct very small floating point errors

        var correction:Number = Math.pow(10, precision);
        return Math.round(correction * number) / correction;
    }

来源：https://stackoverflow.com/questions/2214003/is-there-a-fixed-point-library-for-actionscript-3

标签

apache-flex

actionscript-3

fixed-point