Inner dimensions must agree problem

When running this I get the error message:

Error using  * 
Inner matrix dimensions must agree.

Error in opticaldepth (line 14)
tau(iz,il) = tau(iz,il) + s_abs(il,ij).*sum((Nj(iz:end)*z),ij);

Error in task2 (line 61)
tau = opticaldepth( z,lambda,Nj,s_abs );

It does not work using .* instead.

I get that dimensions doesnt agree, but i thought it did. Can anyone see a solution?

function [ tau ] = opticaldepth( z,lambda,Nj,s_abs )

load('msis20120223_12.dat.txt')    % 621x3 matrix

z = msis20120223_12_dat(:,1);       
nN2 = msis20120223_12_dat(:,2);         
nO = msis20120223_12_dat(:,3);          
nO2 = msis20120223_12_dat(:,4);         

Nj =  [ nN2(:,1) nO(:,1) nO2(:,1) ]; 

load('PhotAbs.dat.txt')

lambda = PhotAbs_dat(:,1);              % 20x3 matrix

sigN2 = PhotAbs_dat(:,2);
sigO = PhotAbs_dat(:,3);
sigO2 = PhotAbs_dat(:,4);

s_abs = [ sigN2(:,1) sigO(:,1) sigO2(:,1) ];  

nz = length(z);                 %621
nl = length(lambda);            %20
dz = gradient(z);
tau = zeros(nz,nl);

      for il = 1:nl,
          for iz = 1:nz,
              for ij = 1:3,
                  tau(iz,il) = tau(iz,il) + s_abs(il,ij).*sum((Nj(iz:end)*z),ij);

              end
          end
      end

tau = opticaldepth( z,lambda,Nj,s_abs );

Answer 1

[James Tursa]

What are you trying to do here?

Nj(iz:end)*z

Nj is a matrix with 3 columns and you are using linear indexing into it, which is probably not what you intended.

[kdyrland]

I'm trying to implement an integral, Nj*dz over z_0 to z_max.