Leila, There could be many reasons for your md calculation taking so long to complete. With two atoms and 5x5x5 grid, reasons could range from your using an executable created with an inefficient compiler and/or without optimized libraries, to a wrong geometric setup, bad calculation settings, heavy basis set (f.e. very long) and many others that do not come to my mind right now. If any of these is the reason, you should correct for them before resorting to more incomplete basis sets, which will compromise the quality of your calculation. Please provide some details on what you are calculating, and an input and output, to check for possible problems.
Marcos El 7 de sep de 2010, 10:25 a.m., "leila" <[email protected]> escribió: Hi, everyone! I did an ab-initio molecular dynamics calculations (MD) by SIESTA with a unit cell containing 2 atoms, using 5 × 5 × 5 k-point grid. The basis and PP are the same as those for the first-principles calculations. I set 100 MD steps with 1.0 fs as the time length. However, the simple test took more than 3 hours by serial processing. This test almost demonstrates the impossibility for ~100 atoms calculations. I wonder if there are any methods, for example using SZ, less K-points, or larger smearing to make ab initio MD calculations feasible. Any advice is welcome! Thanks in advance! Yours sincerely, Leila
