Main Content

subdict

Extract submatrix from a sensing dictionary

Since R2022a

collapse all in page

    Syntax

    Ar = subdict(A,rowIndices,colIndices)

    Description

    example

    Ar = subdict(A,rowIndices,colIndices) returns the submatrix Ar that corresponds to the rows and columns specified by rowIndices and colIndices, respectively.

    Examples

    collapse all

    Open Live Script

    Create a sensing dictionary. Set the type of the sensing dictionary to 'fourier' and 'eye'. The size of each basis type is 100-by-100.

    A = sensingDictionary(Size=100,Type={'fourier','eye'})
    A = 
  sensingDictionary with properties:

                Type: {'fourier'  'eye'}
                Name: {''  ''}
               Level: [0 0]
    CustomDictionary: []
                Size: [100 200]

    Extract the entire submatrix that is associated with the 'eye' basis type. Visualize the submatrix.

    Bmat = subdict(A,1:100,101:200);
imagesc(Bmat)

    Extract a 25-by-50 submatrix associated with the 'fourier' basis type. Visualize the real and imaginary parts of the submatrix.

    Cmat = subdict(A,1:25,1:50);
subplot(1,2,1)
imagesc(real(Cmat))
title("Real Part")
subplot(1,2,2)
imagesc(imag(Cmat))
title("Imaginary Part")

    Input Arguments

    collapse all

    Sensing dictionary, specified as a sensingDictionary object.

    Row indices to extract, specified as a vector.

    Example: Ar = subdict(A,1:256,1:100) returns the 256-by-100 submatrix that corresponds to the rows indexed by 1:256 and columns indexed by [1:100].

    Data Types: double

    Column indices to extract, specified as a vector.

    Example: Ar = subdict(A,1:128,[2 3 5 8 13]) returns the 128-by-5 submatrix that corresponds to the rows indexed by 1:128 and columns indexed by [2 3 5 8 13].

    Data Types: double

    Output Arguments

    collapse all

    Submatrix extracted from the sensingDictionary A, returned as a matrix. The matrix Ar is M-by-N, where M equals the length of rowIndices, and N equals the length of colIndices.

    Data Types: double

    Version History

    Introduced in R2022a

    See Also