gather

R2026b

Collect scattering network properties into local workspace

Since R2023a

Syntax

sn = gather(sf)

Description

sn = gather(sf) collects all the wavelet time scattering network, sf, properties from the GPU device and returns the gathered waveletScattering object sn. All properties of the gathered object are stored in the local workspace.

Examples

Gather waveletScattering object

Refer to GPU Computing Requirements (Parallel Computing Toolbox) to see what GPUs are supported.

Load the noisy Doppler signal. Create a wavelet scattering network gsf that you can apply to the data.

load noisdopp
gsf = waveletScattering;

Copy the signal to the GPU.

gnoisdopp = gpuArray(noisdopp);

Obtain the scattering feature matrix for the scattering network gsf and the data that is on the GPU. Specify the log transformation. Confirm the feature matrix is on the GPU.

gsmat = featureMatrix(gsf,gnoisdopp);
isgpuarray(gsmat)

ans = logical
   1

Obtain the scaling and wavelet filters used in the scattering network.

gfil = filterbank(gsf)

gfil = 3×1 cell array
    1×1 struct
    1×1 struct
    1×1 struct

The first element of gfil contains the scaling filter used in the computation of the zeroth order scattering coefficients. Subsequent elements of gfil contain the wavelet filters and scaling filter for the corresponding filter banks of the scattering decomposition. Confirm all the scaling and wavelet filters are on the GPU.

[isgpuarray(gfil{1}.phift)
isgpuarray(gfil{2}.phift)
isgpuarray(gfil{2}.psift)
isgpuarray(gfil{3}.phift)
isgpuarray(gfil{3}.psift)]

ans = 5×1 logical array

    1
    1
    1
    1
    1

Gather the scattering network. Confirm all the filters in the gathered network sf are in the workspace.

sf = gather(gsf);
fil = filterbank(sf);
[isgpuarray(fil{1}.phift)
isgpuarray(fil{2}.phift)
isgpuarray(fil{2}.psift)
isgpuarray(fil{3}.phift)
isgpuarray(fil{3}.psift)]

ans = 5×1 logical array

    0
    0
    0
    0
    0

Obtain the scattering feature matrix for the scattering network sf and the original signal. Specify the log transformation. Confirm the feature matrix is not on the GPU. Confirm the feature matrix is equal to the matrix obtained using the network gsf.

smat = featureMatrix(sf,noisdopp);
isgpuarray(smat)

ans = logical
   0

xgsmat = gather(gsmat);
max(abs(smat(:)-xgsmat(:)))

ans = 
8.8818e-16

Input Arguments

sf — Wavelet time scattering network

waveletScattering object

Wavelet time scattering network, specified as a waveletScattering object.

Extended Capabilities

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

The gather 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 gather 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).

Version History

Introduced in R2023a

R2026b: Use thread-based environments

You can use gather in thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.