From: Olivier Saut <Olivier.Saut@...>
Date: 2002-12-01T08:17:18+09:00
Subject: Numerical Ruby

Hi all,

I am now using Ruby to test my numerical schemes. Using Ruby for this
task was a real pleasure (I usually code in F90). The computations run
just fine but I would like to have a result a little faster.

My code uses lots of loops as in the following example. 

def faraday
for y in 1..(maxY-1)
 for z in 1..(maxZ-1)   
  @Bx[y,z]+=-(dt/dy)*(@Ez[y+1,z]-@Ez[y,z])+(dt/dz)*(@Ey[y,z+1]-@Ey[y,z])
  @By[y,z]+=  - (dt/dz)*(@Ex[y,z+1]-@Ex[y,z])        
  @Bz[y,z]+=(dt/dy)*(@Ex[y+1,z]-@Ex[y,z])      
  end
 end
end

I am using NArray from Masahiro Tanaka
(http://www.ir.isas.ac.jp/~masa/ruby/index-e.html) to represent the
electromagnetic field.

Is there any way to speed up this type of computations? (I am not sure
how a C extension could help in this case.)

BTW, is there any trend to develop the use of Ruby in the field of
scientific computations (as it seems to be the case with Python)? Will
NArray be included in the standard library?

Thanks!
			- Olivier