Errors & Solutions

[nguyen-group]

• ERROR: Too many bands are not converged from scf or nscf calculations

Solution: increase ecutwfc or decrease conv_thr, or try to do both of them.

• ERROR: S matrix not positive definite

Solution: Run with 'cg' diagonalization might work.

• ERROR: No convergence has been achieved from ph.x

Solution: Reduce alpha_mix(1) in ph.in to 0.3 or 0.1, or the readers can reduce alpha_mix gradually as
alpha_mix(10) = 0.3
alpha_mix (15) = 0.1
That means that you use the default value for alpha_mix (= 0.7) in the first 10 iterations, then you reduce it to 0.3. And after the 15th iteration, you reduce it to 0.1.

• Run linear response calculations (phonons, calculation of Hubbard parameters, etc.) for magnetic insulators with occupations = 'fixed'

Solution: perform a second SCF calculation with fixed occupations by setting total_magnetization and starting from the previous converged SCF calculation (see the procedure described in q-e/HP/examples/example02/README)

• ERROR: Energy error = 0.0E+00 Ry Gradient error = xxx Ry/Bohr

Solution: Increasing the etot_conv_thr and forc_conv_thr values

[Ryusuke-Natsui]

When the sum of k-point is over 90, we have an error. How can we solve it by increasing the max of theta ( the number of k-point)?