c语言 eps(代表很小的值)全称是什么

c语言 eps(代表很小的值)全称是什么

英文全称为epsilon，其来源为希腊字符ε的读音。
ε是希腊语字母之第五字，艾普西隆的小写。
希腊字符在理工学科中，尤其是数学和物理学上，被大量使用。
而ε在数学中的一种含义就是极小的正数。
于是在英文中 epsilon就有了扩展含义，一个极小的正数。
在C中或matlab中延续了这个含义，并简写成eps。

EPS is epsilon. The "close-enough" factor.
The question is "is the absolute value close enough?" Where "close enough" is some small number, often something like 1.0E-3.
Depending on how the algorithm converges on the answer, the performance may depend on the size of EPS. Be careful of making EPS too small, because your process could run for hours (or centuries) and not produce a really usable answer.
In this case -- where there's no loop -- the EPS is used because floating point numbers accumulate small errors during multiplication. You can't simply say
a == b
And have it be true in general. So instead we always sayabs( a-b )<= EPS

罗马符号：Ε ε：艾普西龙 Epsilon
这是按照数学上的惯用法命名的。