JAvascript浮動小数点数演算精度問題
1040 ワード
jacascriptで2つの浮動小数点数を直接加算した結果は正確ではない.以下の方法で解決できる.
function accAdd(arg1, arg2) {
var r1, r2, m, c;
try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }
c = Math.abs(r1 - r2);
m = Math.pow(10, Math.max(r1, r2))
if (c > 0) {
var cm = Math.pow(10, c);
if (r1 > r2) {
arg1 = Number(arg1.toString().replace(".", ""));
arg2 = Number(arg2.toString().replace(".", "")) * cm;
}else {
arg1 = Number(arg1.toString().replace(".", "")) * cm;
arg2 = Number(arg2.toString().replace(".", ""));
}
}else {
arg1 = Number(arg1.toString().replace(".", ""));
arg2 = Number(arg2.toString().replace(".", ""));
}
return (arg1 + arg2) / m
}