Element-wise addition of arrays

[Eduardo Cavazos]

Hello,

Here's a short program which compares via 'benchmark' two ways to 
perform element-wise addition of two arrays.

----------------------------------------------------------------------
import std.stdio ;
import std.date ;
import std.random ;

void main ()
{
   double [2] a ;
   double [2] b = [ uniform ( 0.0 , 1.0 ) , uniform ( 0.0 , 1.0 ) ] ;
   double [2] c = [ uniform ( 0.0 , 1.0 ) , uniform ( 0.0 , 1.0 ) ] ;

   void add ( double [2] a , double [2] b , double [2] c )
   {
     a[0] = b[0] + c[0] ;
     a[1] = b[1] + c[1] ;
   }

   void f0 () { add ( a , b , c ) ; }

   void f1 () { a[] = b[] + c[] ; }

   writeln ( benchmark ! ( f0 , f1 ) ( 10_000_000 ) ) ;
}
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On my system, it seems that 'f1' is slower than 'f0'. Let me know if 
somethings not right with the test program or if there's a better way to 
do the benchmark.

Anywho my question is, in principle, isn't enough information available 
to the compiler such that it can make 'f1' be as fast as 'f0'? I'm just 
wondering if I'll need to make functions like the above 'add' which are 
specific for 2 and 3 element arrays.

Ed