std.math performance (SSE vs. real)

[Walter Bright via Digitalmars-d]

On 6/28/2014 7:01 AM, Andrei Alexandrescu wrote:
> On 6/28/14, 3:42 AM, Walter Bright wrote:
>> Inverting matrices is commonplace for solving N equations with N
>> unknowns.
>
> Actually nobody does that.

I did that at Boeing when doing analysis of the movement of the control 
linkages. The traditional way it had been done before was using paper and pencil 
with drafting tools - I showed how it could be done with matrix math.


> I have an alarm go off when someone proffers a very strong conviction. Very
> strong convictions means there is no listening to any argument right off the
> bat, which locks out any reasonable discussion before it even begins.

So far, everyone here has dismissed my experienced out of hand. You too, with 
"nobody does that". I don't know how anyone here can make such a statement. How 
many of us have worked in non-programming engineering shops, besides me?


> For better or worse modern computing units have focused on 32- and 64-bit float,
> leaving 80-bit floats neglected.

Yep, for the game/graphics industry. Modern computing has also produced crappy 
trig functions with popular C compilers, because nobody using C cares about 
accurate answers (or they just assume what they're getting is correct - even worse).


> I think it's time to accept that simple fact
> and act on it, instead of claiming we're the best in the world at FP math while
> everybody else speeds by.

Leaving us with a market opportunity for precision FP.

I note that even the title of this thread says nothing about accuracy, nor did 
the benchmark attempt to assess if there was a difference in results.