Hello Gentlemen, I have attached gatech.tar, which contains a 2D code based on my paper specnse.f - 2D Navier-Stokes spectral solver (Fourier-Chebyshev) myfftD.f - required VFFTPK routines mylapack.f - required LAPACK routines As before, the code is completely self-contained. Note that the variables are advanced in time Fourier transformed in the x-direction. We only have to transform back to physical space to compute the nonlinear convection terms at each time step. Please take a look and feel free to ask any questions. I have sprinkled the code with some comments, but not extensively. Note that when one takes a derivative spectrally in the periodic direction the 1st and nth coefficients are set to 0! This is why these cases are distinguished. The 1st coeff is for the constant, and the nth is the highest mode which I simply set to 0. The main change to come is computing the Chebyshev differentiation matrices, and their required decompositions for the Poisson solvers, in quadruple precision to avoid significant roundoff errors in the computation of the evals and evectors for, say, N >= 100. This will be done in a stand alone code, and the numbers stored. Again, any questions, just ask! Hans