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exercises:common:sgcp [2025/06/19 02:33] – jglanexercises:common:sgcp [2025/06/19 02:54] (current) – [2. Comparison with CPMD and BOMD] jglan
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 | Feature                          | CPMD          | BOMD         | SGCP                | | Feature                          | CPMD          | BOMD         | SGCP                |
-| SCF at each step                 |  No          |  Yes        |  Partially (predictor-corrector) |+| SCF at each step                 | No          | Yes        |  Partially (predictor-corrector) |
 | Time step                        | Small (~0.1 fs) | Large (~1 fs) | Large (~1–2 fs)           | | Time step                        | Small (~0.1 fs) | Large (~1 fs) | Large (~1–2 fs)           |
 | Conserved quantity preservation  | Excellent     | Reasonable   | Excellent                 | | Conserved quantity preservation  | Excellent     | Reasonable   | Excellent                 |
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 - \( \Xi_I \): Langevin random noise - \( \Xi_I \): Langevin random noise
  
 +
 +
 +====4. How to Set Up in CP2K====
 +
 +
 +| Parameter              | Purpose                                  | Notes                                      |
 +| EXTRAPOLATION_ORDER  | Higher gives better predictor            | 1–4 typical, 0 for metallic is more stable                               |
 +| MAX_SCF_HIST        | Controls SCF correction                  | ≥2 helps smoother convergence              |
 +| STEPSIZE             | Time step in fs                          | ~0.5–2 fs depending on system                |
 +| PRECONDITIONER       | Affects SCF convergence                  | `FULL_SINGLE_INVERSE` slightly better      |
 +| NOISY_GAMMA (γ_D)    | ASPC dissipation compensation            | Adjust to control drift in T and energy    |
 +| GAMMA (γ_L)          | Langevin thermostat strength             | Set to 0 for dissipation-only integration  |
 +
 +1. ASPC Extrapolation
 +
 +  &FORCE_EVAL
 +    &DFT
 +       &QS
 +        EXTRAPOLATION ASPC
 +        EXTRAPOLATION_ORDER 0 # Higher gives better corrector 
 +       &END QS
 +       &SCF
 +        MAX_SCF_HIST 2
 +       &END SCF
 +    &END DFT
 +  &END FORCE_EVAL
 +
 +2. Langevin Thermostat
 +
 +  &MOTION
 +    &MD
 +      ENSEMBLE LANGEVIN
 +      &LANGEVIN
 +        GAMMA 0.005         ! γ_L
 +        NOISY_GAMMA 4.0E-4  ! γ_D
 +      &END LANGEVIN
 +    &END MD
 +  &END MOTION
 +
 +3. Atom-Specific γ_D (Optional)
 +
 +  &THERMAL_REGION
 +    DO_LANGEVIN_DEFAULT TRUE
 +    &DEFINE_REGION
 +      TEMPERATURE 500
 +      NOISY_GAMMA_REGION 4.E-4
 +      LIST 577..745
 +    &END DEFINE_REGION
 +  &END THERMAL_REGION
  
exercises/common/sgcp.1750300389.txt.gz · Last modified: by jglan