Index exceeds matrix dimensions.

Dear all, I have this array, "" ONU_queueNP{N} = [] ""

    ONU_queueNP{i} = [ONU_queueNP{i}; ArrivingTime PacketSize];

and in a line after, I have these instructions:

                Instant = ONU_queueNP{i}(1,1);
                Size = ONU_queueNP{i}(1,1);

So, in Instant' I get the error "Index exceeds matrix dimensions" knowing that this was used before and it does not give an error. What can be the problem please?

Thank you in advance.

[Walter Roberson]

ArrivingTime and PacketSize might both have been empty when you assigned to ONU_queueNP{i}, so ONUP_queueNP{1} might not have an index (1,1)

Note: you probably want Size to be accessed as (1,2)

[Aziza Zaouga]

Thank you for your answer.

But, in fact, i am using a counter that is incremented everytime ONUP_queueNP{i} is filled, so if (counter>0) the ONUP_queueNP{i} is not empty so for sure , it has an index(1,1). So it is the same to use Size. isn't it?

[Walter Roberson]

N = 5;
ONU_queueNP{N} = [];

This would create ONU_queueNP as a cell array of length 4, each containing a 0 x 0 double.

Now, let

global ArrivingTime PacketSize

i = 1;
ONU_queueNP{i} = [ONU_queueNP{i}; ArrivingTime PacketSize]

and observe:

ONU_queueNP =
  1×5 cell array
    {0×0 double}    {0×0 double}    {0×0 double}    {0×0 double}    {0×0 double}

You added an empty row to the end of an empty row, getting an empty row. And now ONU_queueNP{i} is empty so ONU_queueNP{i}(1,1) is index out of range.

[Aziza Zaouga]

Thanks again, But even when I putted [a,b] = size(ONU_queueNP{i})]; I got the same error 'Index exeeds matrix dimensions'. does it mean that there is no column i? thank you

[Walter Roberson]

You could first check size(ONU_queueNP) . If you get index exceeding matrix dimension on that, then check whether you accidentally created a variable named "size"