Repetition is a tedious task, especially when you need to do it more than a few times. This is where Repmat Matlab comes in. It has taken into consideration scenarios where you would require to repeat information. Repmat Matlab allows you to replicate a matrix. Let’s take a closer look at what is Repmat Matlab and how it is used.

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What is Repmat Matlab?

Repmat command is used to repeat the elements of an array in output. Repetition is dependent on the parameter list. Therefore, we must declare parameters within a bracket after the repmat command. Multiple ways to write the repmat function according to the parameter list exist.

When we use repmat to repeat an element more than once, the number of times you must specify each piece repeats within parentheses after the repeated element. 

The [arr] command has three parameters: the name of the array ( arr ), the number of rows (2) and columns (2). When this command executes, it produces two rows and two columns of output that contain the values of each element in your array.

Read More: Introduction to Matlab Matrix

Syntax

Below is the Repmat syntax according to the parameter:

repmat(number, no of rows and columns)

Examples

repmat (75,4)

Arr = repmat(75 , 4 )

>> Untitled

Arr =

75 75 75 75

75 75 75 75

75 75 75 75

75 75 75 75

repmat ( arr,2)

Syntax - repmat (array name, number of rows and columns)

An array is a set of values stored in one variable. The [arr] command is the way to declare an array. It's used to create an array that contains elements, which can be integers, characters, or strings.

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Arrays are helpful because they allow you to store multiple values in one variable. It makes them great for storing lists of items and performing operations on all those items at once.

arr = [ 2  4  3 8 9]

Arr =repmat(arr,2)

arr =

2 4 3 8 9

Arr =

2 4 3 8 9 2 4 3 8 9

2 4 3 8 9 2 4 3 8 9

repmat ( arr, 5,2)

Syntax - repmat (array name, no of rows, no of columns)

arr = [ 54 65 23]

Arr = repmat(arr , 5 ,2)

arr =

54 65 23

Arr =

54 65 23 54 65 23

54 65 23 54 65 23

54 65 23 54 65 23

54 65 23 54 65 23

54 65 23 54 65 23

repmat(arr ,[1 3 2])

Syntax - repmat(arr,[no of rows, no of the column, no of blocks])

If we want to output the block multiple times, we can use this command.

In this case, arr is the name of the array. One is the number of rows, 3 is the number of columns and two is the repetition of the output matrix.

arr = [ 4 2 ; 7 8 ]

Arr = repmat(arr ,[1 3 2])

arr =

4 2

7 8

Arr (:,:,1) =

4 2 4 2 4 2

7 8 7 8 7 8

Arr (:,:,2) =

4 2 4 2 4 2

7 8 7 8 7 8

arr=1:3& arr=( 1:3 ) ‘

Syntax - array name = (range) and array name = (range) ’

In this type, input is a range of numbers. 1:3 represents numbers from 1 to 3 (1, 2, 3) horizontally. And ( 1:3 ) ’ represents numbers from 1 to 3 (1, 2, 3) vertically.

arr = 1:3

Arr = repmat(arr , 3 , 2 )

>> Untitled

arr =

1 2 3

Arr =

1 2 3 1 2 3

1 2 3 1 2 3

1 2 3 1 2 3

arr=(1:3)’

Arr=repmat(arr,3,2)

Arr=

1

2

3

Arr =

1 1

2 2

3 3

1 1

2 2

3 3

1 1

2 2

3 3

Horizontal Vertical

A = (1:3)';  

B = repmat(A,1,4)

B = 3×4

     1     1     1     1

     2     2     2     2

     3     3     3     3

Vertical Implementation

A = 1:4;

B = repmat(A,4,1)

B = 4×4

     1     2     3     4

     1     2     3     4

     1     2     3     4

     1     2     3     4

Conclusion

Repmat is an essential command in array manipulations. It can create an array as well as a matrix. Along with creation, you can also use it for manipulation and mathematical operations.

It is a straightforward method because all you have to do is declare parameters, and you will form the array or matrix.

Matlab is just one of the many tools that are used by Data Scientists. If you want to learn more about different tools and how to master them, including starting your journey as a Data Scientist with our Data Scientist Master’s Program.

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FAQs

1. What is Repmat MATLAB?

You can use the repmat command to repeat the elements of an array in the output. Repetition is based on the parameters you specify in the bracket after repmat—multiple ways to write the repmat function, depending on your parameter list.

2. How do you repeat a value in MATLAB?

u = repmat( v, n ), where v is a scalar or vector, returns a vector of repeated elements of v . If n is a scalar, then each element of v is repeated n times. The length of u is length(v)*n. If n is a vector, it must be the same length as v.

3. How do you extend an array in MATLAB?

If you have an array and assign a value to it at a location past the current size of the array, MATLAB will extend the array. It is acceptable for small array sizes, but it quickly adds up. It involves N*(N+1)/2 memory accesses due to the need to copy every assignment.

4. What is %% in MATLAB?

The per cent sign is used to indicate nonexecutable text within the body of a program. This text is usually used to include comments in your code. Some functions also interpret the per cent sign as a conversion specifier.

5. What is {} used for in MATLAB?

Curly braces are used in cell array assignment statements. For example,

A(2,1) = {[1 2 3; 4 5 6]}, or A{2,2} = ('str').

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