Take values from an matrix automatically.

Hi !!!, Good morning.

I would like to help me in the following:

I have an 18 X 3 matriaz, which can also be 18 X n

Each element of a line is a variable

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clc; clear; close all; format short
Prog=[1.19  1.89  2.74  3.53  4.43  1.76  0.22  4.20  2.39  3.97  3.24  4.43  0.96  6.41  2.00  7.07  3.34  6.77  
  0.56  1.41  2.27  3.23  4.18  1.36  0.96  4.05  1.64  3.66  3.61  3.67  0.53  7.02  2.02  6.30  3.77  6.92  
  1.13  2.16  2.73  3.87  5.08  1.49  0.46  3.80  1.65  4.13  3.62  4.09  0.69  6.86  2.14  6.30  3.31  7.03 ];
% To get each of the elements in a variable I do the following for the first line.
dx1=Prog(1,1);
dy1=Prog(1,2);
dx2=Prog(1,3);
dy12=Prog(1,4);
dx3=Prog(1,5);
dy13=Prog(1,6);
dx12=Prog(1,7);
dy2=Prog(1,7);
dx21=Prog(1,7);
dy21=Prog(1,10);
dx31=Prog(1,11);
dy22=Prog(1,12);
dx13=Prog(1,13);
dy3=Prog(1,14);
dx22=Prog(1,15);
dy31=Prog(1,16);
dx32=Prog(1,17);
dy32=Prog(1,18);
% With this I have each of the values of the first line.
% How do I automatically get the code to take the values of the following lines?

[Ted Shultz]

My first reaction is to ask are you sure you want to extract all the values from the matrix? You can access them in a matrix and skip this step if you wanted. Perhaps you could expand on what you are trying to do?

[Ricardo Gutierrez]

Hi.

Thanks for answering.

The matrix values will be changing in each iteration and those values will be used later in subsequent calculations.

[Bob Thompson]

I think Ted's question is still relevant. I understand that you want to store the matrix information for use outside of a loop, but why not just keep the entire 2D matrix as a 'sheet' in a 3D matrix? I would offer an example, but I have no real idea how your process is organized, so I'm not sure how to make something relevant. The only thing I would say is that you can index the different values you want, instead of creating a variable for each value.

Prog(1,1,i); % dx1 where i is the iteration number you want

Also, before somebody else mentions it, it is generally considered bad practice to generate a lot of variables with sequential naming (i.e. dx1, dx2, dx3, ...). MATLAB is designed to work with values in matrices, so it is always best to try and keep matrices together.

[Walter Roberson]

If you need to take a copy of the current values to use in calculations while you change the array, then you can

saved_row = Prog(i,:);

and then saved_row(6) would be dy13 and so on without having to write each value to a variable individually.

[Ricardo Gutierrez]

Thank you.

Answer 1

[Fabio Freschi]

Prog_old = Prog;

% modify Prog as desired
Prog = Prog*2; % dummy operation

% reload the old version
Prog = Prog_old;

[Ricardo Gutierrez]

Thank you.