make method 32 configurable by one parameter

Prog/main.f90

@@ -108,7 +108,7 @@ Program Main
 
   Integer :: Nwrap, NSweep, NBin, NBin_eff,Ltau, NSTM, NT, NT1, NVAR, LOBS_EN, LOBS_ST, NBC, NSW,split,nodes
   Integer :: NTAU, NTAU1
-  Real(Kind=Kind(0.d0)) :: CPU_MAX 
+  Real(Kind=Kind(0.d0)) :: CPU_MAX, param
   Character (len=64) :: file1
 
   
@@ -118,8 +118,9 @@ Program Main
 #endif
 
 ! split is the variable that denotes the chosen splitting
+! param is a parameter for the methods
 ! nodes denotes the number of integration nodes
-  NAMELIST /VAR_QMC/   Nwrap, NSweep, NBin, Ltau, split, nodes, LOBS_EN, LOBS_ST, CPU_MAX 
+  NAMELIST /VAR_QMC/   Nwrap, NSweep, NBin, Ltau, split, param, nodes, LOBS_EN, LOBS_ST, CPU_MAX 
 
 
   Integer :: Ierr, I,nf, nst, n
@@ -201,7 +202,7 @@ Program Main
    CALL MPI_BCAST(N_Tempering_frequency   ,1,MPI_INTEGER,0,MPI_COMM_WORLD,ierr)
 #endif  
 #endif
-  call init_splittings(split)
+  call init_splittings(split, param)
  
   Call Ham_set
   Call confin 

Prog/splittings.f90

@@ -40,13 +40,16 @@ end subroutine
 !
 ! This routine initializes the database with the various splittings
 !> @ param split this sets the chosensplitting. This is e.g. from a config file.
+!> @param myparam a free param
 
-subroutine init_splittings(split)
+subroutine init_splittings(split, myparam)
     Integer, intent(in) :: split
+    real(kind = kind(0.D0)), intent(in) :: myparam
     integer, parameter :: dp = kind(1.d0)
     Integer :: nrofsplits, n, beg, tmpint, i
     complex(kind = kind(0.D0)) :: alpha, beta, xi, lam, chi
-
+    real(kind = kind(0.D0)) :: ts
+    
     chosensplitting = split
 
     nrofsplits = 41
@@ -391,16 +394,16 @@ splits(30)%Tcoeffs(17) = splits(30)%Tcoeffs(1)
 
     ! CHR_3 3 My first own third order method, designed to be a hermitian sequence of Operators
     call createsplit(splits(32), 4, 4)
-    beta = 1.D0/3.D0
-    splits(32)%Tcoeffs(1) = 1.D0/12.0*CMPLX(6+1/(beta*(beta-1)), -Sqrt((2*beta-1)*(-1+6*beta*(beta-1)**2 ))/(beta*(beta-1)), dp)
-    splits(32)%Tcoeffs(2) = 1.D0/(12*beta*(beta-1.0))*CMPLX(-1.0, sqrt((-1+6*beta*(beta-1)**2 )/(2*beta-1.0)), dp)
+    ts = myparam
+    splits(32)%Tcoeffs(1) = 1.D0/12.0*CMPLX(6+1/(ts*(ts-1)), -Sqrt((2*ts-1)*(-1+6*ts*(ts-1)**2 ))/(ts*(ts-1)), dp)
+    splits(32)%Tcoeffs(2) = 1.D0/(12*ts*(ts-1.0))*CMPLX(-1.0, sqrt((-1+6*ts*(ts-1)**2 )/(2*ts-1.0)), dp)
     splits(32)%Tcoeffs(3) = conjg(splits(32)%Tcoeffs(2))
     splits(32)%Tcoeffs(4) = conjg(splits(32)%Tcoeffs(1))
 
     splits(32)%Vcoeffs(1) = 0.D0
-    splits(32)%Vcoeffs(2) = beta
-    splits(32)%Vcoeffs(3) = 1.D0 - 2.D0*beta
-    splits(32)%Vcoeffs(4) = beta
+    splits(32)%Vcoeffs(2) = ts
+    splits(32)%Vcoeffs(3) = 1.D0 - 2.D0*ts
+    splits(32)%Vcoeffs(4) = ts
 
     ! the variant with m=2 optimized for large step sizes in Blanes 2014, 2. order
     ! We try to exploit the trace property and reduce the computational effort.