Error while using Polyval
显示 更早的评论
While solving a problem using polyval, I encountered an error. Here is the screenshot of the code attached (just the part which focuses on the use of polyval)
It seems that polyval isn't accurate when number of digits of the array exceed 15. I am unable to understand what is the cause of this discrepancy.
采纳的回答
Not all numbers in the vicinity of large values can be exactly represented in double precision. In particular 12345678901234567 is not exactly representable in double.
v = [1:9 0:7];
format longg
p = polyval(v, 10)
s = sym(p)
What's the distance between p and the next largest representable number?
eps(p)
If we add something smaller than eps(p) to p it's not enough to get us to the next largest double precision number.
p2 = p + 0.5;
p == p2 % true
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Entering Commands 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
