stripdims

Remove dlarray data format

Syntax

Y = stripdims(X)

Y = stripdims(X,fmt)

Description

The stripdims function removes the format from a dlarray object.

Y = stripdims(X) returns the dlarray X without any dimension labels. Y is an unformatted dlarray.

Y = stripdims(X,fmt) additionally outputs Y with dimensions ordered according to the dimension labels in the format fmt.

Examples

Remove Data Format from dlarray

Create a formatted dlarray.

dlX = dlarray(randn(3,2,1,2),'SSTU')

dlX = 
  3(S) x 2(S) x 1(T) x 2(U) dlarray


(:,:,1,1) =

    0.5377    0.8622
    1.8339    0.3188
   -2.2588   -1.3077


(:,:,1,2) =

   -0.4336    2.7694
    0.3426   -1.3499
    3.5784    3.0349

Create an array that is the same as dlX but has no dimension labels.

y = stripdims(dlX)

y = 
  3x2x1x2 dlarray


(:,:,1,1) =

    0.5377    0.8622
    1.8339    0.3188
   -2.2588   -1.3077


(:,:,1,2) =

   -0.4336    2.7694
    0.3426   -1.3499
    3.5784    3.0349

Input Arguments

X — Input data

dlarray object

Input data, specified as a formatted or unformatted dlarray object.

fmt — Description of output data dimensions

string scalar | character vector

Description of output data dimensions, specified as a string scalar or character vector.

A data format is a string of characters, where each character describes the type of the corresponding data dimension.

The characters are:

• "S" — Spatial

• "C" — Channel

• "B" — Batch

• "T" — Time

• "U" — Unspecified

For example, consider an array containing a batch of sequences where the first, second, and third dimensions correspond to channels, observations, and time steps, respectively. You can specify that this array has the format "CBT" (channel, batch, time).

If fmt is empty or X is an unformatted dlarray object, then Y is equal to X. Otherwise, if X is a formatted dlarray object, then the stripdims function automatically permutes the output so that it has dimensions in the order specified by fmt. In this case, fmt must be a superset of a permutation of dims(X).

Data Types: char | string

Output Arguments

Y — Unformatted dlarray

unformatted dlarray object

Unformatted dlarray, returned as an unformatted dlarray object that is the same as the input array X, but without any dimension labels. If X is unformatted, then Y = X.

Tips

• Use stripdims to ensure that a dlarray behaves like a numeric array of the same size, without any special behavior due to dimension labels.

• ndims(X) can decrease after a stripdims call because the function removes trailing singleton dimensions.

  X = dlarray(ones(3,2), 'SCB');
  ndims(X)

  ans =
  
       3

  X = stripdims(X);
  ndims(X)

  ans =
  
       2

Extended Capabilities

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

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

GPU Arrays

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

The stripdims function supports GPU array input with these usage notes and limitations:

• When at X has underlying data of type gpuArray, this function runs on the GPU.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced in R2019b