OpenEuphoria

Re: Minimum & Maximum

• Posted by jiri babor <jbabor at PARADISE.NET.NZ> Sep 25, 1998
• 687 views

Michael Palffy wrote:

>How's this..
>
>function max(sequence a, sequence b)
>        return a *(a>=b) + b *(b>a)
>        end function

Now we are really cooking, echos of c.r.white...

First of all, just a minor thing, Mike, you probably want to change
the parameter type from a sequence to an object, to cover plain atoms
as well as sequences. So your min and max functions become

    function min(object a, object b)
        return a*(a<=b) + b*(b<a)
    end function

    function max(object a, object b)
        return a*(a>=b) + b*(b>a)
    end function


Nice and short, and it works! (I does not happen all that often on
this list )

But (there is almost always a 'but' lurking somewhere in everything!)
these function have no explicit type checking that all the previous
suggestions had. So it gives me a chance to ask a question I wanted to
ask anyway: do we really need those explicit checks? And I think, we
do not! The compiler itself will eventually tell us, anyway, if we try
something stupid, illegal. The error message may be a bit more cryptic
('an attempt to subscribe an atom', or whatever...), but we will not
get away with it. And these superfluous checks always slow things down,
sometimes considerably!


Now a treat for the benchmark freaks. I stripped my minimum function
down to

function minimum(object a, object b)
    if atom(a) then
        if b<a then a=b end if
    else
        for i=1 to length(a) do
            a[i]=minimum(a[i],b[i])
        end for
    end if
    return a
end function

to make it more directly comparable with Mike's.

The times are in seconds for 1,000,000 iterations on my 233 MHz
Pentium II, 64 Mb ram, under Win95, the same simple set as in my
previous post, tick_rate(1000):

                                           Mike's          Mine
================================================================
min(5,3)                                    1.14           0.91
min({5,3,1},{-5,2,6})                       6.69           6.89
min({5,3,{4,5},1},{-5,2,{-7,7},6})         11.82          13.27

Not much in it!  jiri