Matteo Cencini

Last seen: 10 months ago | Active since 2015

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How to create 3D Fourier matrix?
I would like to create a Fourier matrix for a 3D fourier transform. I know that for 1D FFT in Matlab it can be created with dftm...

8 years ago | 0 answers | 0

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Lsqr first iteration without any initial guess
I am trying to solve argmin||Ax-B|| using lsqr with a function handle and without any initial guess. I thought that lsqr would h...

8 years ago | 0 answers | 0

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Question

lsqr result strongly depends on weights
I need to solve argmin||W*FT^-1(Ax)-W*p|| using lsqr. p is image, x is k-space matrix, A is a matrix and W is a weighting matrix...

8 years ago | 1 answer | 0

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Question

lsqr converged but returns large residual
I'm using lsqr. It converges, but I get this message: lsqr converged at iteration 10 to a solution with relative residual 0....

8 years ago | 1 answer | 0

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Question

Creating huge fourier matrix
I need to minimize ||FT^-1(Ax-B)|| using lsqr. A is a huge matrix which I had to define using spalloc. Since fft() can't handle ...

8 years ago | 1 answer | 0

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answer