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# Convert Matrix to Vector in Simulink

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Fabian Gock on 31 Jul 2017
Commented: Honglei Chen on 31 Jul 2017
I want to convert a matrix like:
m= [t1 v1
t2 v2
t3 v3
t4 v4]
(where t are values representing the time and v are the actual values)
into a vector
v=[v1
v2
v3
v4]
attempts using the selector block failed, because I don't really know how to use it, and the documentation is not really clear to me.
I also tried using a Matlab code block.
function [voltage, current] = matrix2vector(u, i)
u(:,2)=[];
i(:,2)=[];
voltage = u;
current = i;
and
function [voltage, current] = matrix2vector(u, i)
voltage = u(:,2);
current = i(:,2);
But i get the error: Index expression out of bounds. Attempted to access element 2. The valid range is 1-1. More information
Function 'MATLAB Function' (#35.83.84), line 4, column 15: "2"
Thank you in advance -Fabian

#### 1 Comment

Fabian Gock on 31 Jul 2017
I don't have the DSP System Toolbox. So I can't use the Variable Selector..

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### Answers (1)

Honglei Chen on 31 Jul 2017
You should be able to use Selector to do it. In your dialog,
set Number of input dimensions to 2 set Index mode to one based set the first dimension as Select All set the second dimension as Index vector (dialog) and then enter 2
I've attached a snapshot for your reference. Does it address your issue?

#### 2 Comments

Fabian Gock on 31 Jul 2017
Thank you for your quick answer. I tried your suggested way but I got the following error
Maybe it is important to know that the matrix i want to convert is imported from the Workspace using a From Workspace block.
Honglei Chen on 31 Jul 2017
This means that you don't have a matrix. Rather you only have a column vector at the selector input. Maybe what you get is already the value itself? Unless you provide more info regarding how the original input is organized and how the from Workspace is configured, it's hard for others to guess what the issue might be.

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