inseti: example

Example of input parameters to run start not with default parameters.

Contents

Description

If you want to run start not with the default parameters you can set the fields in struct seti in this or another file in the folder inseti and refer to this file by Parameter inseti.

Attention in usage of the framework

Syntax and Example

inseti = 'example';
start

Input Parameters of struct seti

Note that this are some, but not all input parameters.

% -- dirname: suffix
seti.dirSuffix = '_test';   % Suffix of the folder created in folder |output| to store the results

% -- setGrid
seti.dim = 2;       % dimension of scattering problem (2 or 3)
                    % Make sure to choose a suitable contrast in seti.contrast.
seti.rCD = 0.2;     % size of computational domain |[-rCD,rCD]^dim|
seti.nCD = 256;     % number of discretization points in each dimension

% -- setKernel
seti.k = 250;               % wave number
seti.model = 'helmholtz';   % input helmholtz will choose automatically
                            % helmholtz2D or helmholtz3D dependent on the dim

% -- setContrast
seti.contrast = 'cornerBallSparse2D';
% Set the name of contrast function as string (files in folder |incontrasts|).
% Make sure to choose the correct dimension of the problem in |seti.dim|.
% A list of available contrasts is in setContrast.

% -- expSetup (set experimental set-up)
seti.incPntsType = 'circle';    % Geometry: type of transmitters
seti.measPntsType = 'circle';   % Geometry: type of receivers
seti.incNb = 35;                % Geometry: number of transmitters
seti.measNb = 35;               % Geometry: number of receivers
seti.radSrc = 5;                % Geometry: radius of sphere containing transmitters
seti.radMeas = 5;               % Geometry: radius of sphere containing receivers
% Fore more details of geometry type circle and further geometries like square and borehole, see |pntsGeometry|.
seti.incType = 'pointSource';   % Type of incident fields: 'pointSource' or 'planeWave'
seti.measType = 'nearField';    % Type of measurements: 'nearField' or 'farField'

% -- reconstruction
seti.invNo = 6;                 % Do not change in published code (no other option).
seti.delta = 0.01;              % Relative noise level (for noisy simulated data and assumed in reconstruction process to stop by discrepancy principle)
seti.physBounds = [-1,3,0,3];   % Bounds for real/imaginary part of contrast: [reMin, reMax, imMin, imMax]
seti.alpha = 500;               % Regularization parameter of sparse penalty term
seti.beta = 1E-5;               % Regularization parameter of total variation penalty term
seti.useDis = 1;                % 1, then discrepancy principle is used to stop reconstruction process (outer iteration)
seti.tau = 2.5;                 % Discrepancy principle stops at parameter \tau \delta
seti.nOut = 30;                 % Maximal number of reconstruction steps (outer iteration)

% -- reconstruction with PDA
seti.pdaN = 50;                 % number of inner iteration steps (PDA)
seti.pdaStepsize = 'fix';       % how primal and dual stepsizes in pda are choosen
                                % 'fix' (tau = sigma = 1/L).
                                % In our experience you should not change it.

% -- figures and files
seti.plotFreq = 1;              % Frequency to plot outer iteration (0: no plot)
seti.plotPublish = 1;           % 1: plot design for publication (e.g. without title)
                                % see plot2DstylePublish.m and plot3DstylePublish.m
seti.usecbarlim = 1;            % 1: set limits of colorbar manually (0: automatically)
seti.cbarlim = [-0.2, 1.4];     % limits vor colorbars [cbarmin, cbarmax]

seti.savepng = 1;               % 0 or 1, save figures as *.png (default: 1)
seti.saveepsc = 0;              % 0 or 1, save figures as colored *.eps (default: 0)
seti.savefig = 0;               % 0 or 1, save figures as *.fig (default: 0)

seti.savedata = 1;              % 0 or 1, saves relative discrepancy, error
                                % and difference of computed contrast to its predecessor
                                % as save_dis.mat, save_err.mat and
                                % save_dif.mat in folder output.

More About

References

[1] Florian Bürgel, Kamil S. Kazimierski, and Armin Lechleiter. A sparsity regularization and total variation based computational framework for the inverse medium problem in scattering. Journal of Computational Physics, 339:1-30, 2017. URL: https://doi.org/10.1016/j.jcp.2017.03.011.

See Also