Unable to perform assignment because the left and right sides have a different number of elements.

Hi all,

I am trying to divide a two line (two times) based on different length as the following code:

but I can not

clear all 
clc
t                                       =       [2 0.40 1.2];        
t_ID                                    =       [3  1];                 %  Each line index    


Z                                       =       zeros(2+1,1);
for j = 1:2
  if (j == 1)
        t1 = 0; t2 = t(t_ID(j));
        Z(j) = linspace(t1,t2,2);
   else
        t1 = Z(2*j-1);
        t2 = t1+t_av(t_ID(j));
        Z(2*j-1:2*j) = linspace(t1,t2,2);
  end
end

% Z should be [0 0.2 0.3250]

Answer 1

[Walter Roberson]

First get rid of the "clear all". Your code relies on variables being in memory, but the clear destroys them.

Z(j) = linspace(t1,t2,2);

linspace requesting two output elements is never going to fit a scalar destination. Also linspace requesting two output elements would just be the vector [t1, t2] so just code that instead of confusing things.

When j becomes 2 then 2*j-1 would be 3 so you would be writing to locations 3 and 4 in the vector. Your code will never create a vector of odd length.

[sci hub]

@Walter Roberson

Thanks for your reply.. the thing is not every time t1 and t2 not every time are the same...

I even tried with with Z(j) but still not working ??

would you please clarify what you could modify ?

[Walter Roberson]

How is the 0.3250 to be caclulated?

The 0.2 output looks like the mean of 0 and 0.40 but with t_ID being 3 and 1, then the second entry in t should not be part of the calculation at all.

Start by writing your code as if you were not using a for loop, just a series of statements like

j = 1;
Z(j) = <something>
j = 2;
Z(j) = <something>
Z(j+1) = <something>

and we will see if we can work out the rules from there.

[sci hub]

@Walter Roberson

Thank you again..

sorry was a typo, meant::

Z(1)=0

Z(2)=1.2

Z(3)=2

the first line is =1.2 so divided by 2 = [0 1.2] and the second line is: 2 but first point of the second line is the last point of the first line and so on..

is it clear now ???

[Walter Roberson]

Something like no loop but

Z = [0, t(t_ID)]

[sci hub]

@Walter Roberson

Thanks again.. I think I did not explain it correct.. here are two different examples manually.. (i am trying to make matlab calculate them ..

• First case two lines only

the first line is =1.2 so divided by 2 = [0 1.2] and the second line is: 2 but first point of the second line is the last point of the first line and so on.. so should be z=[0 1.2 1.2+2]

Second case three lines

the first line is =1.2 so divided by 2 = [0 1.2] and the second line is: 2 but first point of the second line is the last point of the first line and first point of the third line is the last point of second line

.. so should be z=[0 1.2 1.2+2 1.2+2+2]

I think adding for loop is mandatory

[Walter Roberson]

Z = cumsum([0, t(t_ID)]) ;

[sci hub]

@Walter Roberson

Sounds working, but if I wanna divide the line into more two or more pieces, it will not work.. it will not give the correct data.. no change......

so any suggestions ???