matrix business in D

[Yura]

Dear all,

Thank you for your replies!

Regarding Julia - it seems to be interesting, but - it is too 
fresh, and from what I understood, it is not compiled. I think D 
language would be more interesting for me and suitable for my 
needs (scientific computing).

Yes, numpy/scipy is OK, but since I have now some time I would 
like to learn one compiled language which is more close to the 
hardware,

"I have done some linear algebra in D. If you are comfortable
calling C functions, you can easily call into existing solutions,
because it is trivial to call into C from D."

This is very interesting since as you know lots of code is 
written in c. GSL is a good example. The only problem is how to 
use it. The thing is that i don't know c, but the question is 
whether I really need to be skilled in c to be able to call c 
functions. My gut feeling is that no, I don't need to be skilled. 
I have installed gsl on my computer. But what I need is a good 
example of a code/codes on how to call this library from d 
programming language. E.g. I have tried to use gsl. I have 
written a code in c (simple.c):

-------
#include <stdio.h>
#include <gsl/gsl_sf_bessel.h>

double fun(double x)
//main (void)
{
//  x = 5.0;
   double y = gsl_sf_bessel_J0 (x);
//  printf ("J0(%g) = %.18e\n", x, y);
   return y;
}
----------------
Also, I have written a di file (simple.di):
----------------
extern (C):
double fun(double);
----------------
And finally, d code (simple.d):
------------------
import std.stdio, std.string, std.array;
import std.conv;

import std.stdio;
import simple;

void main(){
     writeln( fun(10.0) );
}
------------------------------------

Unfortunately, when I compile it it says:

dmd simple.d simple.o
simple.d(8): Error: undefined identifier fun

Could one provide a working clear example how to use gsl in D?

I have tried SciD and it apparently works, though I did not test 
it so far. I think a tutorial on how to use D in scientific 
programming would be very appreciated and could attract more 
people to D.

PS Thank all of you for helping.












I use Gretl
http://gretl.sourceforge.net/ because it offers a convenient
interface to commonly used BLAS and LAPACK functionality. GSL is
another good choice https://www.gnu.org/software/gsl/. This has
worked well for me because I am using D as a drop-in replacement
for C."





On Thursday, 17 October 2013 at 20:31:38 UTC, Yura wrote:
> Dear D programmers,
>
> I am very new to D programming language. I just started to 
> learn it as an alternative to python since the latter sometimes 
> is too slow. My question is whether there some simple ways to 
> solve linear algebra problems in D programming language? E.g. 
> matrix multiplication, diagonalization, SVD decomposition? If 
> there is something, I would definitely stick to D programming 
> language in my projects.
>
> PS I am not a proffesinal programmer and I am sorry if this 
> question has already been discussed.
>
> Thaks in advance!