Mathematica 7 compares to other languages

[sln at netherlands.com]

On Thu, 25 Dec 2008 21:50:29 +0000, Jon Harrop <jon at ffconsultancy.com> wrote:

>Xah Lee wrote:
>>> >On Dec 10, 2:47 pm, John W Kennedy <jwke... at attglobal.net> wrote:
>>> >> C:
>>>
>>> >> #include <stdlib.h>
>>> >> #include <math.h>
>>>
>>> >> void normal(int dim, float* x, float* a) {
>>> >>     float sum = 0.0f;
>>> >>     int i;
>>> >>     float divisor;
>>> >>     for (i = 0; i < dim; ++i) sum += x[i] * x[i];
>>> >>     divisor = sqrt(sum);
>>> >>     for (i = 0; i < dim; ++i) a[i] = x[i]/divisor;
>>>
>>> >> }
>> 
>> Due to the low level of C, this C example should perhaps then accept a
>> sequence of numbers separated by space...
>
>In other words, you want a REPL.
>
>Why don't we have another challenge that involves handling a non-trivial
>input format, i.e. parsing?

Maybe you could speed it up.

sln

----------------------------------
void normal (int Dimension, double *X, double *A)
{
     double *xp, *ap, divisor, sum;
     int i;

     for ( i=0, sum=0., xp=X; i<Dimension; i++, xp++)
          sum += (*xp) ** 2;
     divisor = sqrt ( sum );
     for ( i=0, ap=A, xp=X; i<Dimension; i++, ap++, xp++)
          *ap = *xp / divisor;

     // if Dimension is greater than
     // sizeof double X[] or double A[] it will GPF.
     // this is a really, really bad design.
}