DEHam/README.md

DEHam

Double Exchange Hamiltonian: Complete Version

1. Dependencies

1. PETSc and SLEPc

2. IRPF90

3. Compiling

4. Export environment variables for PETSc and SLEPc

export PETSC_DIR=${PATH_TO_PETSC_INSTALLATION}
export SLEPC_DIR=${PATH_TO_SLEPC_INSTALLATION}

2. Make the executable

make ex1

3. Using DEHam

1. The DEHam program requires an input file which has the topology of the Hamiltonian and the various parameters as explained below in a sample inputfile:

140                 # The total number of determinants
7                   # The largest number of non-zero elements per row
2                   # The number of processors used in parallel
1                   # The number of holes
0                   # The isz (ms-1/2) value
1,2,3,1,2,3,4,5,6,7 # The topology of the system is specified here
2,3,4,8,7,6,5,6,7,8 # first and second line contain the two sites linked
1,1,1,2,2,2,2,3,3,3 # third line contains the type of link (1 for t, J 2 for K and 3 for none)
.1430,-0.20,0.0000  # The three types of links this line gives J, K
.1430,-0.20,0.0000  # 
-1.00,0.0,0.00      # This line gives t

2. running DEHam

mpiexec -n [nprocs] ./ex1 inpfile