unshiftdata

Inverse of shiftdata

Syntax

y = unshiftdata(x,perm,nshifts)

Description

y = unshiftdata(x,perm,nshifts) restores the orientation of data x that was shifted using the shiftdata function with permutation perm.

Note

Use the unshiftdata function in tandem with the shiftdata function. These functions are useful for creating functions that work along a certain dimension, like filter, goertzel, sgolayfilt, and sosfilt.

Examples

Permute Dimensions of a Magic Square

This example shifts x, a 3-by-3 magic square, permuting dimension 2 to the first column. unshiftdata shifts x back to its original shape.

Create a 3-by-3 magic square.

x = magic(3)

x = 3×3

     8     1     6
     3     5     7
     4     9     2

Shift the matrix x to work along the second dimension. The permutation vector, perm, and the number of shifts, nshifts, are returned along with the shifted matrix.

[x,perm,nshifts] = shiftdata(x,2)

x = 3×3

     8     3     4
     1     5     9
     6     7     2

perm = 1×2

     2     1

nshifts =

     []

Shift the matrix back to its original shape.

y = unshiftdata(x,perm,nshifts)

y = 3×3

     8     1     6
     3     5     7
     4     9     2

Rearrange Array to Operate on First Nonsingleton Dimension

This example shows how shiftdata and unshiftdata work when you define dim as empty.

Define x as a row vector.

x = 1:5

x = 1×5

     1     2     3     4     5

Define dim as empty to shift the first nonsingleton dimension of x to the first column. shiftdata returns x as a column vector, along with perm, the permutation vector, and nshifts, the number of shifts.

[x,perm,nshifts] = shiftdata(x,[])

x = 5×1

     1
     2
     3
     4
     5

perm =

     []

nshifts = 
1

Using unshiftdata, restore x to its original shape.

y = unshiftdata(x,perm,nshifts)

y = 1×5

     1     2     3     4     5

Input Arguments

x — Data

vector | matrix

Data, specified as a vector or matrix.

Data Types: single | double

perm — Permutation

vector

Permutation, specified as a vector.

Data Types: single | double

nshifts — Number of shifts

scalar

Number of shifts, specified as a scalar. nshift is returned by the shiftdata function.

Data Types: single | double

Output Arguments

y — Restored data

vector | matrix

Restored data, returned as a vector or matrix.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced in R2012b

R2024b: unshiftdata supports C/C++ code generation

The unshiftdata function supports C/C++ code generation. You must have MATLAB^® Coder™ to use this functionality.