🚀 go-pugleaf

In article <4466@brazos.Rice.edu> preston@titan.rice.edu (Preston Briggs) writes:
>In article <PCG.90Feb1164820@rupert.cs.aber.ac.uk> 

>>	for s[] over c[*,], ronly h[] over a[*,]
>>	for p over s[*], ronly v[] over b[,*]
>>	  p = h innerprod v
>>
>>	(ronly h[]) innerprod (ronly v[]) is
>>	  let fast d initially 0
>>	  for fast ronly h_i over h[*], fast ronly v_j over v[*]
>>	    d += h_i*v_j;
>>	  return d

>If you'd throw out the "ronly" and "fast" hints, I'd say these
>forms aren't too bad.  Why do you need to say "ronly" when it's
>fairly obvious to the compiler that h and h_i are not assigned?

Following up my own posting, ...

I'd like a compiler to make code to make the computer do what I want.
Unfortunately, it can't read minds, so I have to write a program
to give it a hint.  Since it's so stupid, I have to be fairly 
specific about how it's to do things like multiplying matrices.
On the other hand, an optimizing compiling allows me to avoid
too much tedium.

Strength reducers are good enough that I don't need to mess
with pointer variables.  Various forms of redundancy elimination
are good enough that I needn't bother about every little common
subexpression.  Vectorizers are good enough so that I need not
manually insert vector primitives.  Register allocators are
good enough that I need not scatter register declarations about.
Constant propagation is strong enough so that I can afford
to declare some constants in convenient places, without bothering about
folding every constant expression by hand.  And all these optimizations
work exceptionally well on the inner loops that consume so much time.

The optimizer is written once, by the compiler writer.
I, on the other hand, write many programs and I'm able to
take advantage of the optimizer in all my programs.
It costs compile time, but it's cheaper to use the computer
to optimize my code than to do it by hand.

Optimizers can't do everything.  They don't parallelize Fortran
very well, for example.  A better language would probably be
a good alternative.  But why should we do what the computer
can do well?

Preston Briggs
preston@titan.rice.edu