On Tue, Aug 2, 2016 at 11:45 AM, Random832 <random832@fastmail.com> wrote:
Sure, but what the standard doesn't say is exactly what sequence of
comparisons is entailed by a clamp function.

def clamp(x, a, b):
    if x < a: return a
        if x > b: return b
        else: return x

def clamp(x, a, b):
    if a <= x:
        if x <= b: return x
        else: return b
    else: return a

There are, technically, eight possible naive implementations, varying
along three axes:

Exactly-- I thought this was self evident, but apparently not -- thanks for spelling it out.
All such functions are equivalent if {a, b, x} is a set over which the
relational operators define a total ordering, and a <= b. However, this
is not the case if NaN is used for any of the arguments.

Exactly again -- NaN's are kind of a pain :-(

As for the convert to floats issue -- correctness is more important than performance, and performance is probably most important for the special case of all floats. (or floats and integers, I suppose) -- i'm sure we can find a solution. LIkely something iike the second option above would work fine, and also work for anything with an ordinary total ordering.



Christopher Barker, Ph.D.

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