integrator tps2ab + tps2ee in first step

integrators/__init__.py

@@ -27,6 +27,8 @@ from commics.integrators.kw1_mps import KW1_MPS
 from commics.integrators.tps1_kw2 import TPS1_KW2
 from commics.integrators.tps1_mps import TPS1_MPS
 
+from commics.integrators.tps2ab_initial_tps2ee import TPS2AB_INITIAL_TPS2EE
+
 __all__ = \
   [ "Integrator" \
   , "DUMMY" \
@@ -36,4 +38,5 @@ __all__ = \
   , "TPS1HEE" \
   , "TPS1HEE_MPS" \
   , "KW1_MPS", "TPS1_KW2", "TPS1_MPS" \
+  , "TPS2AB_INITIAL_TPS2EE"
   ]

integrators/tps2ab_initial_tps2ee.py

+###  TPS2+AB + TPS2EE for first time step ###
+from . import tps2ab
+
+
+################################################################################
+
+
+class TPS2AB_INITIAL_TPS2EE(tps2ab.TPS2AB):
+  '''
+  implements TPS2AB from second time-step on,
+  BUT: At first time step use TPS2EE = EE approximation of pi, i.e., pi(v) := 0
+  '''
+
+
+#------------------------------------------------------------------------------#
+
+
+  def _DerivLinearTerms_pi_Implicit_RHS(self):
+    return self._ZeroCF()
+
+
+#------------------------------------------------------------------------------#
+
+
+################################################################################