Re: matrix package with Ada

[Ada novice <posts@gmx.us>]

On Jul 12, 5:13 pm, jonathan <johns...@googlemail.com> wrote:
> On Jul 12, 2:38 pm, Ada novice <po...@gmx.us> wrote:
>
>
>
> > On Jul 10, 10:22 pm, Gautier write-only <gautier_niou...@hotmail.com>
> > wrote:
>
> > > > And are there other alternatives or other packages?
>
> > > Look there - excellent stuff:
> > >  http://www.csee.umbc.edu/~squire/adaclass/gnatmath95/
> > > The most amazing: add some "Ada." for the basic matrix packages
> > > referenced, and you get Ada 2005 compatibility.
>
> > > G.
>
> > I've tried to compile the file test_generic_complex_eigenvalues.ada
> > provided in this package (http://www.csee.umbc.edu/~squire/adaclass/
> > gnatmath95/) but it doesn't compile successfully. And The matrix
> > package from Drexel doesn't have any eigenvalues/eigenvectors
> > computation routine at all.
>
> > Looking at all this, I'm tempted to say how silly it is that Ada
> > doesn't provide good numerics capabilities. Ada 05 brought a big
> > improvement with more vector and matrix operations though it can't
> > handle the eigenvalues computation of a non-symmetric matrix. The next
> > version of Ada I read will be out in 2 years. I hope that there will
> > be better facilities for scientific programming in Ada than there is
> > today. Those on the Ada community should be made aware of the need for
> > more scientific computing power in Ada.
>
> > There are many libraries for Fortran and C/C++ for numerical
> > computations while Ada doesn't seem to have a decent one. One cannot
> > expect people to switch to Ada if there are no good numerical
> > computing libraries. Ada has been here for more than 25 years now but
> > maybe has remained confined to military applications for many years.
> > However free compilers are out there since many years and I hope that
> > good programmers with good understanding of numerical methods will be
> > motivated to have bindings for Ada.
>
> > YC
>
> OK, after a bit of trouble I got it to run (using the latest gnat/gcc
> compiler). There's 1 bug to fix 1st: around line 150 of the package
> body
>
>     generic_complex_linear_equations.adb
>
> you need to change a line to initialize X with a complex number.
>
>   --X(N) := 0.0; -- change this to:
>     X(N) := COMPOSE_FROM_CARTESIAN( 0.0 , 0.0 ) ;
>
> Finally, if you using GNAT, the file names have to end in either
> .adb or .ads
>
> The instructions for that are at the top of each file. For example
> the test procedure should end in .adb if you are using gnat.
>
> Notice also that you have to download quite a few packages to get
> the eig-stuff to work.  The compiler error messages should tell you
> if you are missing anything.
>
> Finally! The test routine is user unfriendly.  (I hope you fix it up
> for the rest of us.) You have to enter numbers.  First enter the
> size of the matrix
> (type the number 2, then enter.)
> then enter one by one the 4 elements of the complex matrix, say:
> (1.0, 2.0)
> (2.0, 2.2)
> (3.0, 2.4)
> (4.0, 2.6)
>
> I'm just guessing that that is what the program wants, but
> it seemed to run when I tried it.
>
> J.
>
> numbers.

Many thanks for your kind efforts. Now it works fine. I'm using the
gnat compiler. I have made some quick tests with this package and
compared the results with those from Matlab. The results match for the
eigenvalues. I just need some more time to see how the eigenvectors
are scaled. It is indeed very nice to see at last a package which
delivers!

The program doesn't exit well however. When the program
(test_generic_complex_eigenvalues.ada) it will display the results but
in my GPS editor the line 102 is highlighted. This is where the
program stops. If the program would run fine then I would have finally
got this line displayed: DONE test_generic_complex_eigenvalues (at the
bottom of test_generic_complex_eigenvalues.ada). Do you have the same
problem?


I'm still a novice in Ada and still learning. This is why I couldn't
fixed the bug in the package myself. Thus I thank you much again for
looking into the problem. Yes it would be nice to be able to call the
routine from a main program. I will work on that when time permits but
first things first: I will have to check the scaling used for the
eigenvectors.


YC