Nufftn yields only zeros for nonuniform grid. Bug?

Question

schlapp 2020-4-28

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/521297-nufftn-yields-only-zeros-for-nonuniform-grid-bug

编辑： schlapp 2020-4-29

采纳的回答： Chris Turnes

pcrop.mat

在 MATLAB Online 中打开

Following up a previous question from myself on this site, I decided to ask again about my second point more precisely.

My main issue is that in my test-case of a simple Gaussian the built-in MATLAB function 'nufftn' only gives a matrix of zeros as a result when using the nonuniform grid 'pcrop.mat', provided in the attachment.

in other words:

fcrop = exp(-(pcrop.^2 + pcrop'.^2 + pcrop.*pcrop'));
ftcrop = reshape(nufftn(fcrop,{pcrop,pcrop'},{pcrop,pcrop'})/2/pi,length(pcrop),length(pcrop));

yields 'ftcrop' as 2d matrix full of zeros.

Performing the same task with a interpolated uniform grid

puni=[pcrop(1):2*pcrop(end)/(length(pcrop)-1):pcrop(end)];
funi = exp(-(puni.^2 + puni'.^2 + puni.*puni'));
ftuni = reshape(nufftn(funi,{puni/sqrt(2*pi),puni/sqrt(2*pi)'},{puni/sqrt(2*pi),puni/sqrt(2*pi)'})/2/pi*(2*puni(end)/length(puni))^2,length(puni),length(puni));

gives the correct matrix 'ftuni'.

Is this a bug, or am I using the function in a wrong way? Unfortunately I dont get any error messages.