How to subtract two close numbers?
2 次查看(过去 30 天)
显示 更早的评论
Hi!
I've compiled the code below and i don't know why it doesn't give exact zero.
I'll appreciate if someone helps me.
format long
x=5.4;
y=x-5;
z=y-0.4;
disp(z)
0 个评论
采纳的回答
Stephen23
2019-10-16
编辑:Stephen23
2019-10-16
"..i don't know why it doesn't give exact zero."
The decimal values 5.4 and 0.4 cannot be represented exactly using binary floating point numbers, in just the same way that you cannot write 1/3 using a finite decimal fraction.
Use num2strexact see the precise decimal values of the closest floating point binary numbers:
The behaviors of floating point numbers are quite well documented, you need to learn how to write your code taking them into account. Start by reading these:
etc.etc.
This is worth reading as well:
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Waveform Generation 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!