# 1.3. Solver settings¶

The following options change how the solver behaves. These should be added to a data file and loaded to the simulation cases through pyramses.case.addData. For instance:

import pyramses
case = pyramses.cfg()

$LATENCY aver_time_window latency_early_stop ; Parameters for latency [AFC14]. Parameters • aver_time_window (float (seconds)) – The averaging window that we compute latency on. • latency_early_stop (binary (0/1 for no/yes)) – When all the units get latent, should the simulation stop. $GP_REFRESH_RATE interval ;

Modifies the interval at which the runtime observables are shown.

Parameters

interval (float (seconds)) – Interval value. Default is 1.

$OBS_BUFFER_SIZE size ; The internal memory reserved for the observables. Change this to be less than half of your available RAM. Parameters size (float (GB)) – Memory value. Default is 8 GB. $OMEGA_REF reference ;

Defines the reference frame for the system.

Parameters

reference (str) – ‘COI’ for centre of inertia or ‘SYN’ for synchronous reference frame. Default is ‘COI’.

$NEWTON_TOLER nettol blocktol1 blocktol2 ; Defines the Newton method convergence tolerance. Parameters • nettol (float) – Network tolerance. Default 1e-3. • blocktol1 (float) – Injector absolute tolerance. Default 5e-4. • blocktol2 (float) – Injector relative tolerance. Default 5e-4. $S_BASE size ;

Defines the system base power.

Parameters

size (float (MVA)) – Nominal base power. Default is 100 MVA.

$NB_THREADS num ; Defines number of threads for parallelisation. Parameters num (int) – Number of threads. Should be less than the physical cores of your system. Default is 1. $FIN_DIFFER C1 C2 ;

Defines numerical differentiation step used for the Jacobian calculations.

Parameters
• C1 (float) – constant C1 for numerical evaluation of Jacobian (user-defined blocks). Default 1e-5.

• C2 (float) – constant C2 for numerical evaluation of Jacobian. where change in x = max( C1 abs(x), C2). Default 1e-5.

$SPARSE_SOLVER name ; Defines the solver used for the sparse system solution. Parameters name (str) – ‘ma41’ or ‘KLU’. Default is ‘KLU’. $SKIP_CONV bool ;

Defines if the converged blocks are skipped to accelerate the simulation.

Parameters

bool (boolean) – T of F. Default is F.

$FULL_UPDATE bool ; Defines if the Jacobian matrices will be updated at every iteration. Parameters bool (boolean) – T of F. Default is F. $DISP_PROF bool ;

Displays the profiling of the execution to identify the computationally intensive parts.

Parameters

bool (boolean) – T of F. Default is F.