numerical gradient with extra-large data size

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Yu Li 2018-1-16

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编辑： Walter Roberson 2018-1-17

Hi:

I have a 3D coordinate with significantly large size: 1e9*3.

and I have value of parameter at each of these points such as T: 1e9*1.

now I need the gradient of T at each direction, such as dT/dx, dT/dy, dT/dz.

is there anyway to do this?

Thanks!

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Walter Roberson 2018-1-16

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You might be able to take advantage of "tall arrays" https://www.mathworks.com/help/matlab/tall-arrays.html

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Walter Roberson 2018-1-17

See https://projecteuclid.org/download/pdf_1/euclid.rmjm/1250127676 for a discussion of algorithms, and http://www.tandfonline.com/doi/pdf/10.1080/02626667409493918 for more information on the one they recommend.

But I wonder what you are headed for?

http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281994%29122%3C1611%3AUOMIFM%3E2.0.CO%3B2 "Use of Multiquadric Interpolation for Meteorological Objective Analysis "

http://www.worldscientific.com/worldscibooks/10.1142/6437 "Meshfree Approximations in MATLAB"

Yu Li 2018-1-17

编辑：Walter Roberson 2018-1-17

Hi:

thanks for your reply. I will read these papers and see if I could find any solution.

the original data sets are come from a high fedelity CFD code using large eddy simulation (LES), the CFD software only exports the velocity but no velocity gradient. but we need the gradient to do further analysis.

Thanks!

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