wfdavis@davis-inc.com <wfdavis@davis-inc.com> wrote:

> With regard to algorithms, here are two schemes.  b(i) and g(i)
> refer to the i-th bit of the n-bit binary and Gray-code
> representations, respectively. The symbol X stands for exclusive OR.
>
> Binary to Gray-code conversion:
>
> g(i) = b(i) X b(i+1)     where i = 0,1,2,...n-1
> g(n) = b(n)

    Warren:

    This is wrong... Try it and you'll see.

    The CORRECT algorithm is g(i) = b(i) ^ (b(i) >> 1), where "^"
    means "xor" and ">> 1" means "right-shifted 1 bit".

> Gray-code to binary conversion:
>
> b(n) = g(n)
> b(i) = g(i) X b(i+1)     where i = n-1,...2,1,0

    This is also wrong, of course.

    -Andy

=== Andrew Warren - fastfwd@ix.netcom.com                 ===
=== Fast Forward Engineering - Vista, California          ===
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