Re: C++ fluency

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 9 May 2009 04:48:50 -0700 (PDT)

Message-ID:

<2130bf78-50aa-429d-b317-defb57e39de0@v4g2000vba.googlegroups.com>

On May 8, 9:20 pm, Noah Roberts <n...@nowhere.com> wrote:

James Kanze wrote:

On May 7, 5:15 pm, Noah Roberts <n...@nowhere.com> wrote:

I don't know. I don't know of anyone who's come up with an
answer either.

And yet, there are multithreaded programs which work
correctly. (Admittedly, not very many.) And programs using
floating point which work correctly.

I haven't worked on anything that needed floating point
testing more than abs(f() - expected) < (tolerance *
expected). That doesn't mean that others haven't found ways
to unit test these things; I just haven't and don't know of
any.

The problem is the non-linearity, and the fact that the
requirements often specify less that 1/2 LSB precision. If your
tests prove that you have this for the input of 1.0, and of 2.0,
you still can't claim it for all of the intermediate values.

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