Re: Reading files in Octave

[Przemek Klosowski]

   I'm attempting to read a file of spherical harmonic coefficients of    the 
form:

                        2   0   0.202150907893000000e-03  
                       0.000000000000000000e+00
                        3   0   0.121260448837000000e-04  
                       0.000000000000000000e+00
                       ....

One not very elegant way is:

     a=fscanf(fopen('gravfile'),"%f")
     i=a(1:4:end), j=a(2:4:end)
     Cl=sparse(i+1,j+1,a(3:4:end))
     Sl=sparse(i+1,j+1,a(4:4:end))

It would have been nicer but strangely less readable to:

     a=fscanf(fopen('gravfile'),"%f");
     a=reshape(a,4,length(a)/4)';
     Cl=sparse(a(:,1)+1,a(:,2)+1,a(:,3))
     Sl=sparse(a(:,1)+1,a(:,2)+1,a(:,4))

I am sure that others will show how to write it more nicely--
for instance, I don't remember if there's a way to read 
directly into a 4xN shape, so that reshape() is not needed.

   In Octave I attempted to do the same thing using fscanf:

                    [ j, k, Cl(j+1,k+1), Sl(j+1,k+1), KOUNT ] = fscanf(
                   gravfile, "%i %i %e %e", "C" );

   Octave returns an error message stating that k is undefined.

I think that's because Octave tries to read the whole file in the right-hand
statement, rather than implicitly iterating, setting variables like Fortran.