SIMD support...

[F i L]

On Monday, 16 January 2012 at 17:57:38 UTC, suicide wrote:
> Here is mine:
> http://suicide.zoadian.de/ext/math/geometry/vector.d
> i haven't tested (not even compiled) it yet. It needs 
> polishing, but i have not much time to work on it atm. But you 
> may use it as you wish ;)
> Any suggestions/improvement is welcome.
>
> Greetings,
> Felix
>
>
>
> Am 16.01.2012, 04:00 Uhr, schrieb Walter Bright 
> <newshound2 at digitalmars.com>:
>
>> On 1/15/2012 6:54 PM, JoeCoder wrote:
>>> On 1/15/2012 1:42 PM, Walter Bright wrote:
>>>>
>>>> A nice vector math library for D that puts us competitive 
>>>> will be a nice
>>>> addition to Phobos.
>>>
>>> The gl3n library might be something good to build on:
>>> https://bitbucket.org/dav1d/gl3n
>>>
>>> It looks to be a continuation of the OMG library used by 
>>> Deadlock, and is
>>> similar to the glm (http://glm.g-truc.net) c++ library which 
>>> emulates glsl
>>> vector ops in software.
>>>
>>> We'd need to ask if it can be re-licensed from MIT to Boost.
>>
>> I have never used libraries like that, and so it isn't obvious 
>> to me what a good one would look like.

Nice start, though it have quite a few issues.

1. for (i; 0 .. D) needs to be: foreach (i; 0 .. D)
2. asserts(r != 0) should be done in a contract
3. 'Vector(D, T)' can be internally used as just 'Vector'
4. instead of making opAdd, opSub, opMul, etc.. use opBinary and 
mixins
5. don't pass vectors as 'ref' unless they are going to be 
modified
6. for performance, don't pass all values through 'real'

    auto opBinary(string op, U)(U r)
    if (U.sizeof <= T.sizeof && isImplicitlyConvertible(T, U))
    in {
        assert(r != 0);
    }
    body {
        Vector nvec(this);
        foreach (i; 0 .. D)
            mixin("nvec.vec[i]" ~ op ~ "= r;");
        return nvec;
    }


    auto opBinary(string op, U)(U r)
    if (U.sizeof > T.sizeof && isImplicitlyConvertible(U, T))
    in {
        assert(r != 0);
    }
    body {
        Vector nvec(this);
        foreach (i; 0 .. D)
            mixin("nvec.vec[i]" ~ op ~ "= cast(T) r;");
        return nvec;
    }

    . . . . .

    auto opBinary(string op, V, U)(Vector!(V, U) vec)
    if (U.sizeof <= T.sizeof && isImplicitlyConvertible(U, T))
    in {
        foreach (i; 0 .. V)
            assert(vec.vec[i] != 0);
    }
    body {
        Vector nvec(this);
        static if (D <= V) {
            foreach (i; 0 .. D)
                mixin("nvec.vec[i]" ~ op ~ "= vec.vec[i];");
        }
        else {
            foreach (i; 0 .. V)
                mixin("nvec.vec[i]" ~ op ~ "= vec.vec[i];");
        }
        return nvec;
    }


    // etc...

Something along those lines. Also, make sure you can't create a 
vector of zero or one length (struct Vector(D, T) if (D >= 2) { 
... }). Plus, none of your Vector(D,T) instances will compile 
because you for the '!' mark: Vector!(D, T)