matlab - 四舍五入到 n 位有效数字

Question

我正在尝试在 MATLAB 中编写代码，将数字四舍五入到某些(如我所要求的)有效数字。

我不知道该怎么做。有什么建议吗？

Answer 1

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

舍入到d 十进制数:

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

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

编辑

实际上更简单:round函数支持这些选项:

>> 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