Index exceeding number of array elements on second iteration of loop

Apologies if this has been answered previously but I could not see an answer specific to my case. Im modelling the damage properties properties over a number of cycles (c). Theres a number of while loops within while loops if that makes any difference.

A single point is itervatively solved (DELTA_plot,P_plot) if:

            if(length==Sp)                                      
                if(abs(ddelta_dx(y))<tol&&abs(DELTA(y))<tol)     
                  DELTA_plot = DELTA_initial;                      
                  P_plot          = Prl_in;                              
            end
        figure(1)  
        title('Plot of Load (P) - Global Deformation (Δ) Relationship')    
        xlabel('Deformation Δ (mm)')     
        ylabel('Load P (kN)')    
        plot(DELTA_plot(c),P_plot(c),'.'); hold on;                     
        grid       

This works for the first cycle (c=1), which plots a linear relationship. However when I repeat the exact same code for the second cycle, with different initial parameters, the following error appears:

"Index exceeds the number of array elements (1)."

plot(DELTA_plot(c),P_plot(c),'.'); hold on;

What am I doing wrong? If i try to plot as follow:

        plot(DELTA_plot,P_plot,'.'); hold on; 

It does not plot correctly.

Please let me know if you require any additonal information and thanks for any help.

Answer 1

[Mathieu NOE]

hello

your variables are not indexed , so this is no surprise that it will fail at the second iteration

code should be , assuming c is the current loop index :

                if(abs(ddelta_dx(y))<tol&&abs(DELTA(y))<tol)     
                  DELTA_plot(c) = DELTA_initial;                      
                  P_plot(c)          = Prl_in;                              
            end

[Thomas Sibly]

Thanks for the response mate.

When I change the code to:

if(abs(ddelta_dx(y))<tol&&abs(DELTA(y))<tol)     
   DELTA_plot(c) = DELTA_initial;                      
   P_plot(c)          = Prl_in;                              
end

The following error appears:

"Unable to perform assignment because the indices on the left side are not compatible with the size of the right side."

DELTA_plot(c) = DELTA_initial;

This error occurs in the first cycle now.

Additionally, If I were to make the code:

if(abs(ddelta_dx(y))<tol&&abs(DELTA(y))<tol)     
   DELTA_plot(c) = DELTA_initial(y);                      
   P_plot(c)          = Prl_in(y);                              
end

The original error appears, also for the first cycle:

"Index exceeds the number of array elements (1)."

Any idea what is causing that issue?

[Mathieu NOE]

well , I don't know what your code is supposed to do and what size are variables DELTA_initial and Prl_in and if their size is constant or not as you loop ?

what size are you expecting the result DELTA_plot and P_plot to be ?

are you willing to share the entire code ?