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<div class="PlainText">Hi Saikat,<br>
<br>
I have attached a usr file that shows how to calculate finite difference based first derivative of the first passive scalar t(1,1,1,1,2) using the current time step and two previous time steps. The coefficients for the derivative are obtained using a call to
fd_weights_full, and I am using a common block for storing the values of the scalar at two previous time-steps.
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Ketan<br>
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