why do I get this error in the simulation

I'm doing a reactor simulation and it's a long one and it works but now when I add some changes I got this error

Error using griddedInterpolant

The grid vectors must contain unique points.

Error in interp1 (line 161)

F = griddedInterpolant(X,V,method);

Error in reactor_simulation>cross (line 431)

Sig_s_tot_O16_interp = interp1(oxygen_energy_tot, oxygen_cross_tot, e, 'linear');

Error in reactor_simulation>dist2c (line 505)

value = - log ( u ) / cross ( e );

Error in reactor_simulation (line 215)

[ d, seed ] = dist2c ( e, seed );

as I understand that the error because the data file I use does not has a unique points (the energy) so I used this code to found the simller points and I change them to became unique

for i=1:max(size(oxygen_data_tot))-1

if(oxygen_data_tot(i,1)==oxygen_data_tot(i+1))

i=i

end

end

but the problem is that I got the same error again after changing all the poin, so can you help me to know whats the problem to solve it?

Answer 1

[Torsten]

Before calling "interp1", use

% Sort array oxygen_energy_tot in ascending order
[oxygen_energy_tot_sorted,idx_sort] = sort(oxygen_energy_tot);
oxygen_cross_tot_sorted = oxygen_cross_tot(idx_sorted);
% Delete duplicate values of oxygen_energy_tot
[oxygen_energy_tot,idx_unique] = unique(oxygen_energy_tot_sorted);
oxygen_cross_tot = oxygen_cross_tot_sorted(idx_unique);

[Moza]

I got this error:

Undefined function or variable 'idx_sorted'.

Error in reactor_simulation>cross (line 426)

oxygen_cross_tot_sorted = oxygen_cross_tot(idx_sorted);

Error in reactor_simulation>dist2c (line 508)

value = - log ( u ) / cross ( e );

Error in reactor_simulation (line 211)

[ d, seed ] = dist2c ( e, seed );

[Torsten]

Use

[oxygen_energy_tot_sorted,idx_sorted] = sort(oxygen_energy_tot);

instead of

[oxygen_energy_tot_sorted,idx_sort] = sort(oxygen_energy_tot);

[Moza]

thank you it workes