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Hi;
I want to simulate diffusion motion using Einstein diffusion equation (x=sqrt(2Dt)). If I have a tensor with nonzero elements, what is the diffusion constant in x,y,z direction which should be used in the mentioned formula?Is it correct that diagonal term are used?
Thank you in advance for your help.

Yes, the value you should use for D in your simple model is the ADC, which is the average of the diagonal elements in your matrix.