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| author | Eugeniy E. Mikhailov <evgmik@gmail.com> | 2021-01-29 16:23:05 -0500 |
|---|---|---|
| committer | Eugeniy E. Mikhailov <evgmik@gmail.com> | 2021-01-29 16:23:05 -0500 |
| commit | 3983eb46023c1edd00617729ba929057fda8d0bd (patch) | |
| tree | 816ad084f355000656c43da9160f1c257bbb1ddc /Measurements/A_f.m | |
| download | l1magic-1.11.tar.gz l1magic-1.11.zip | |
Initial import from https://statweb.stanford.edu/~candes/software/l1magic/v1.11
Additional Clean up of Mac dirs and tex generated files
Diffstat (limited to 'Measurements/A_f.m')
| -rw-r--r-- | Measurements/A_f.m | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/Measurements/A_f.m b/Measurements/A_f.m new file mode 100644 index 0000000..3a793aa --- /dev/null +++ b/Measurements/A_f.m @@ -0,0 +1,30 @@ +% A_f.m +% +% Takes "scrambled Fourier" measurements. +% +% Usage: b = A_f(x, OMEGA, P) +% +% x - N vector +% +% b - K vector = [real part; imag part] +% +% OMEGA - K/2 vector denoting which Fourier coefficients to use +% (the real and imag parts of each freq are kept). +% +% P - Permutation to apply to the input vector. Fourier coeffs of +% x(P) are calculated. +% Default = 1:N (no scrambling). +% +% Written by: Justin Romberg, Caltech +% Created: October 2005 +% Email: jrom@acm.caltech.edu +% + +function b = A_f(x, OMEGA, P) + +N = length(x); +if (nargin < 3), P = 1:N; end + +fx = 1/sqrt(N)*fft(x(P)); +b = [sqrt(2)*real(fx(OMEGA)); sqrt(2)*imag(fx(OMEGA))]; + |