ismatrix
Determine whether input is matrix
Syntax
Description
Examples
Arrays of Different Sizes
Determine whether arrays of different sizes are matrices.
Create an array of size 1-by-3. Determine whether it is a matrix.
A1 = zeros(1,3); TF = ismatrix(A1)
TF = logical
1
Create an empty array of size 0-by-3. Determine whether it is a matrix. A 2-D empty array is a matrix.
A2 = zeros(0,3); TF = ismatrix(A2)
TF = logical
1
Create an array of size 1-by-3-by-2. Determine whether it is a matrix. A 3-D array is not a matrix.
A3 = zeros(1,3,2); TF = ismatrix(A3)
TF = logical
0
Determine Matrix from Three-Dimensional Array
Create a 3-D array and determine whether the array elements are a matrix.
First define a 2-D array of size 2-by-3. Determine whether it is a matrix.
A = [0.1 0.2 0.5; 0.3 0.6 0.4]
A = 2×3
0.1000 0.2000 0.5000
0.3000 0.6000 0.4000
TF = ismatrix(A)
TF = logical
1
To create a 3-D array, add a third dimension to the array A
. Assign another 2-by-3 matrix to the third dimension of A
with index value 2.
A(:,:,2) = ones(2,3)
A = A(:,:,1) = 0.1000 0.2000 0.5000 0.3000 0.6000 0.4000 A(:,:,2) = 1 1 1 1 1 1
Check whether the 3-D array of size 2-by-3-by-2 is a matrix.
TF = ismatrix(A)
TF = logical
0
Now determine whether the array elements of A
are a matrix. Check whether the second page of the 3-D array is a matrix. The syntax A(:,:,2)
uses a colon in the first and second dimensions to access all rows and all columns.
TF = ismatrix(A(:,:,2))
TF = logical
1
Check whether the second row of the 3-D array is a matrix. The syntax A(2,:,:)
uses a colon in the second and third dimensions to include all columns and all pages.
TF = ismatrix(A(2,:,:))
TF = logical
0
A(:,:,2)
is a matrix since it is a multidimensional array of size 2-by-3. However, A(2,:,:)
is not a matrix since it is a multidimensional array of size 1-by-3-by-2.
Determine Matrix from Character Vector and String
Create an array of characters. Determine whether it is a matrix.
A = 'Hello, World!';
TF = ismatrix(A)
TF = logical
1
Check the dimension of A
using size
. A
is a matrix of size 1-by-13.
size(A)
ans = 1×2
1 13
Now create a string scalar by enclosing a piece of text in double quotes.
A = "Hello, World!";
Check whether the scalar A
of size 1-by-1 is also a matrix.
TF = ismatrix(A)
TF = logical
1
Input Arguments
A
— Input array
scalar | vector | matrix | multidimensional array
Input array, specified as a scalar, vector, matrix, or multidimensional array.
Extended Capabilities
Tall Arrays
Calculate with arrays that have more rows than fit in memory.
The
ismatrix
function fully supports tall arrays. For more information,
see Tall Arrays.
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.
Thread-Based Environment
Run code in the background using MATLAB® backgroundPool
or accelerate code with Parallel Computing Toolbox™ ThreadPool
.
This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.
GPU Arrays
Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.
The ismatrix
function
fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray
(Parallel Computing Toolbox). For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).
Distributed Arrays
Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.
This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).
Version History
Introduced in R2010b
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