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Topic: Numerical analysis -- basic terminological question.
Replies: 0

 Paul Posts: 780 Registered: 7/12/10
Numerical analysis -- basic terminological question.
Posted: Oct 10, 2012 5:41 AM

Suppose I write an implementation for a function that is usually conceived of as an inverse. For example y = asin(x) [inverse sine].

There are two standard ways to check my implementation. One is simply to compare with a trusted version (for example from mathworks).

The other would be to compute (for a large number of values)
abs(sin(asin(x)) - x) where asin is my function [of course, one needs to assume that sin works with sufficient accuracy]. What is the name for the latter testing technique? Would it be called "substitution"?

[The above absolute value is not always close to 0, I realise. But that's a little bit irrelevant to my terminological question. Assume that x is in a quadrant such that the absolute value is theoretically 0].

Thank You,

Paul Epstein