I was running some transmission spectra calculations for Graphene junction device. I used multi grid solver keeping Neumann boundary condition for electrodes and Dirichlet for central regions .K points were kept as 1X1X51 using extended huckel device calculator.The calculation is running fine but i am getting warning messages in the log as shown below.What i should do to correct this?
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# WARNING
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# The computed multigrid residual is greater than the required accuracy.
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# Computed residual : 1.29180e-010
# Required accuracy : 1.00000e-012