The logical indices contain a true value outside of the array bounds

Please, how can I tackle "The logical indices contain a true value outside of the array bounds" error? I don't what exactly is the cause.

load('sol_active_flow_varinying_xiL.mat')

xi=xivals;
L =Lvals;

intabsul = intabsul;                 
intabsur =intabsur;        
absintul =absintul;        
absintur =absintur;         

%% This is where I having an issue
test1 = intabsul == absintul & intabsur == absintur;
subset_xi_1 = xivals(test1);

The logical indices contain a true value outside of the array bounds.

subset_Lv_1 = Lvals(test1);

test2 = intabsul ~= absintul & intabsur ~= absintur;
subset_xi_2 = xivals(test2);
subset_Lv_2 = Lvals(test2);
%
test3 = intabsul ==absintul & intabsur ~= absintur;
subset_xi_3 = xivals(test3);
subset_Lv_3 = Lvals(test3);
%
test4 = intabsul ~= absintul & intabsur == absintur;
subset_xi_4 = xivals(test4);
subset_Lv_4 = Lvals(test4);

[Catalytic]

Please stop posting your code in monospaced font. Not only is it hard to read, but people cannot copy/paste it as conveniently as when you put it in a Code block. Note the buttons -

[jessupj]

look at sizes of things.... your intabsul and other vars are 20x20 matrices, but xivals is a 20-lenght vector. that's why it gives you that error at xivals( some logical function of intabsul)

It' means you're trying to assign test1 a value e.g.

xivals(11,20)

that doesn't exist

[Stephen23]

"I don't what exactly is the cause."

The cause is very simple: you are trying to access an array element that does not exist. For example:

V = 1:3

V = 1×3

1 2 3

V([false,false,true,false]) % okay

ans = 3

V([false,false,false,true]) % error: does element (1,4) exist? (hint: no)

The logical indices contain a true value outside of the array bounds.

Now take a close look at the sizes of your arrays.

[University]

Okay, thank you

[Fangjun Jiang]

This is the exact same question you asked previously. The cause of the problem has been clearly explained with a simple example. You have your data and you can run your code line by line, observe the value of the variable and see what is not expected and figure out a solution.

Without comments and with those confusing variable names, it's really hard to try to understand what the program tries to achieve. If you want help, you have to explain to an extent that others can understand.

[University]

Sorry, Fangjun. From the above explanation, deos mean that xivals has to 20 by 20 matrix for it work?? I just want to get the values of xivals and Lvals if this contidition: "intabsul ~= absintul & intabsur ~= absintur" is satisfied My xivals and Lvals is a vecor of length 20 each.

Answer 1

[Fangjun Jiang]

test2 = intabsul ~= absintul & intabsur ~= absintur

the resulting "test2" is a 20x20 logical matrix. You can't use it to index a vector of 20 elements.

Do you actually want the index only if the "whole column" or "whole row" of "test2" is all true? If yes, you need to use the all() function, apply it on the column or row.

In this cases, there are three rows of "test2" are all true

test2 = intabsul ~= absintul & intabsur ~= absintur;
index=all(test2,2);
subset_xi_2 = xivals(index)
subset_Lv_2 = Lvals(index)

subset_xi_2 =

  111.8421  118.4211  125.0000


subset_Lv_2 =

   1.0e-05 *

    0.5967    0.6317    0.6667

[University]

Oh I see, thank you so much for your explanation. I understand how it works now.