diff options
| author | schnetter <schnetter@578cdeb0-5ea1-4b81-8215-5a3b8777ee0b> | 2005-12-11 17:39:27 +0000 |
|---|---|---|
| committer | schnetter <schnetter@578cdeb0-5ea1-4b81-8215-5a3b8777ee0b> | 2005-12-11 17:39:27 +0000 |
| commit | d36b4fc36a2336187dbb51cf76a9cca67d933482 (patch) | |
| tree | 4af1b97ebdc40915ecfd3bc0f5e2767377e737b4 /src | |
| parent | 929dc70879d304e70b627fdecb0b9c7e6a8ddd93 (diff) | |
Correct critical error in the RK45 time integrator.
The current time and the time step sizes were not set correctly. That
led to first order convergence instead of fifth order convergence.
git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@101 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b
Diffstat (limited to 'src')
| -rw-r--r-- | src/SetTime.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/src/SetTime.c b/src/SetTime.c index 94380b1..af044f4 100644 --- a/src/SetTime.c +++ b/src/SetTime.c @@ -47,6 +47,16 @@ int MoL_ResetDeltaTime(CCTK_ARGUMENTS); ********************* Local Data ***************************** ********************************************************************/ +/* RK45 coefficients */ +static const CCTK_REAL alpha_array[6] = { + 0.0, + 1.0/4.0, + 3.0/8.0, + 12.0/13.0, + 1.0, + 1.0/2.0, +}; + /******************************************************************** ********************* External Routines ********************** ********************************************************************/ @@ -198,6 +208,14 @@ int MoL_ResetTime(CCTK_ARGUMENTS) 0.5*(*Original_Delta_Time)/cctkGH->cctk_timefac; } } + else if (CCTK_EQUALS(ODE_Method,"RK45")) + { + const int substep = MoL_Intermediate_Steps - (* MoL_Intermediate_Step); + cctkGH->cctk_time + = ((* Original_Time) + + ((alpha_array[substep] - 1) + * (* Original_Delta_Time) / cctkGH->cctk_timefac)); + } #ifdef MOLDEBUG printf("MoL has once more reset t (%d): %f.\n", *MoL_Intermediate_Step, cctkGH->cctk_time); @@ -276,6 +294,13 @@ int MoL_ResetDeltaTime(CCTK_ARGUMENTS) cctkGH->cctk_delta_time = 2.0/3.0*(*Original_Delta_Time); } } + else if (CCTK_EQUALS(ODE_Method,"RK45")) + { + const int substep = MoL_Intermediate_Steps - (* MoL_Intermediate_Step); + cctkGH->cctk_delta_time + = ((alpha_array[substep + 1] - alpha_array[substep]) + * (* Original_Delta_Time)); + } #ifdef MOLDEBUG printf("MoL has once more reset dt (%d): %f.\n", *MoL_Intermediate_Step, |