四舍五入到有效数字

Question

我正在尝试在MATLAB中编写代码,以便将数字舍入到某些(如我所知)有效数字.

我不知道怎么做.有什么建议？

Answer 1

要舍入到d 有效数字:

>> d = 3; %// number of digits
>> x = 5.237234; %// example number

>> D = 10^(d-ceil(log10(x)));
>> y = round(x*D)/D
y =
    5.2400

要舍入到d 十进制数字:

>> d = 3; %// number of digits
>> x = 5.237234; %// example number

>> D = 10^d;
>> y = round(x*D)/D
y =
    5.2370

编辑

实际上它更容易:该round功能支持以下选项:

>> d = 3;
>> x = 5.237234;
>> y = round(x, d, 'significant')
y =
    5.2400

>> d = 3;
>> x = 5.237234;
>> y = round(x, d) %// or y = round(x, d, 'decimals')
y =
    5.2370