porting arapck code to octave

[David Bateman]

Jaroslav Hajek wrote:
> 1. rather than your MY_LOCAL_BUFFER, you can use the pre-defined
> OCTAVE_LOCAL_BUFFER_INIT.
>
> 2. the following snippet:
> 		  for (octave_idx_type i = 0; i < n; i++)
> 		    workd[i+ipntr[1]-1] = static_cast<double>(i) * workd[i+ipntr[0]-1];
> is obviously not multiplying by diag(1:100), but by diag(0:99).
>
> 3.
> 	      retval(1) = eig_val;
> 	      retval(2) = eig_vec;
>
> should read
>
> 	      retval(0) = eig_val;
> 	      retval(1) = eig_vec;
>
> after correcting these problems, I get the correct answer:
> ans =
>
>     97.000
>     98.000
>     99.000
>    100.000
>
> regards
>
>
>   

Unfortunately, that doesn't work for me as it never gets to point 3) and 
in any case point 2) would just mean the eigenvalues that are found 
should be [99, 98, 97, 96]... The code has an internal error in the 
arpack function dsaupd (error number -9999).. However, as it seems to 
work for you the question is why it works for you and not me...

Basically, I can only see compiler/linker issues as a reason at the 
moment.. I compiled with gfortran version 4.3.2 and the flags

FFLAGS  = -O2 -fPIC

and linked dssimp.oct against the shared version of the library. What 
did you do differently?

D.


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