Dear QE community, I have struggled for over a year to obtain reliable SCF elastic constants with thermo_pw when ionic relaxation is enabled. I know this query is more relevant to the thermo_pw community, unfortunately i haven't got any response from the themo_pw community so I am reaching out to this forum in anticipation:
The themo_control file is: &INPUT_THERMO what = 'scf_elastic_constants', frozen_ions = .FALSE. / With `frozen_ions=.TRUE.` everything converges, but setting `.FALSE.` aborts with ``` *task # 0from bfgs : error # 1dE0s is positive which should never happen* ``` Lowering thresholds (etot_conv_thr) yields elastic constants, yet the values swing wildly (tens of GPa's) with minute changes in energy tolerances, given that the system I am working on is of low-symmetry (triclinic). Additionally,following adjustments didn't yield any success: - `trust_radius_max` reduced to 0.05 a.u. - tighter `conv_thr`, `etot_conv_thr`, `forc_conv_thr` - `ion_dynamics='fire'` and `'damp'` (BFGS still invoked in thermo_pw) Has anyone resolved this coupled QE and thermo_pw issue or identified safer optimization settings (e.g., alternative algorithms, pre-relax procedures, or recommended `trust_radius_max`) that stabilize the calculation? Any guidance or example inputs would be greatly appreciated, I will be happy to share my input files if needed. Thank you for your time. Best regards, Vinay Maithani IIT Kharagpur On Tue, Mar 4, 2025 at 12:08 PM Vinay Maithani < [email protected]> wrote: > Dear QE community, > > I am currently utilizing thermo_pw to compute the self-consistent field > (SCF) elastic constants for various materials. While setting > frozen_ions=.TRUE. in the &INPUT_THERMO namelist yields successful > results, attempts with frozen_ions=.FALSE. lead to the following error: > > *task # 0 > from bfgs : error # 1 > dE0s is positive which should never happen* > > To address this issue, I have implemented several strategies without > success: > > 1. Reducing the trust_radius_max parameter to as low as 0.05. > 2. Adjusting convergence thresholds within the input file. > 3. Modifying ion_dynamics to 'fire' and 'damp'; however, the > optimization persists with the BFGS algorithm. > > I seek your guidance on resolving this error to facilitate accurate > elastic constant calculations with ionic relaxation. > > Thank you for your assistance. > > -- > Regards, > Vinay Maithani > Department of Metallurgical and Materials Engineering > Indian Institute of Technology, Kharagpur >
_______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
