I’m trying to solve a basis pursuit denoising problem uinsg tfocs_SCD.
I figured I would start by using the default options and tweak them to suit my needs.
Unfortunately, it seems like there is a bug in the defaults provided by tfocs_SCD.
This is a snippet from my code
opts = tfocs_SCD(); % get the default options opts = rmfield(opts, 'adjoint');% this seems to fix a bug % in tfocs_SCD they invert the value of opts.adjoint in line 92 % so i remove the parameter and let them set it back to the default ... [x, out, optsOut] = solver_sBPDN_W(A, WWt_rw, y, ... epsilon, mu, x, lambda0, opts, cont_opts);
Without my ‘fix’, this is the error message I get
Error using tfocs_initialize (line 294) The elements in the last column must be constants. Error in tfocs_AT (line 13) tfocs_initialize
Am I doing something wrong?
In reply to Stephen Becker:
Lines 41-44 have been replaced by lines 35-38 that are RIGHT above them. Line 39 is particularly confusing because both the if statement and the expression to be evaluated are on the same line.
In my original question, I made reference to lines 92, here is the relevant code
% The affine quantities will be used in adjoint orientation if isfield( opts, 'adjoint' ), opts.adjoint = ~opts.adjoint; else opts.adjoint = true; end
It seems very strange to be that opts.adjoint is inverted … The default opts return adjoint=true, then this inverts it, maybe it was meant to be a double negative?
opts.adjoint = ~~opts.adjoint
I need more than 10 karma to attach a file, so I’ve just copied the contents below.
Note, I just made a toy example and I’m not too interested if some of the parameter choices are entirely correct.
clear all; close all; % define the vector space and number of measurements N = 100; m = 30; k = 3; % sparsity % Make a sparse target x = zeros(N, 1); x(randperm(N, k)) = 1; A = 2*(randi([0, 1], m, N) -0.5); y = A *x; W = @(x_) x_; Wt = @(x_) x_; epsilon = 0.1; mu = 0.01; opts = tfocs_SCD(); opts.debug = true; % Comment out the line below to see the magic working %opts = rmfield(opts, 'adjoint'); % this seems to fix a bug WWt = linop_handles([N, N], W, Wt); x_guess = A\y; lambda_guess = ; x_reconstructed = solver_sBPDN_W(A, WWt, y, epsilon, mu, x_guess, lambda_guess, opts); figure hold on plot(x, 'vb') plot(x_reconstructed, '^r');
---- Aug 22 2013 —
hmm, ok, I didn’t realize that adjoint was an internal parameter. Is there any reason why line 92 would ever need to be executed (maybe other solvers need it)? If there isn’t, why not simply remove the if statements around line 94 and let
opts.adjoint = true;