Description: 
        This program implement a ``quantum electron bath'' with a
        1D spin chain. The electron hopping part is tight binding 
        model and spin part is Heisenberg model, the interaction 
        between electron and spin is exchange effect.

Parameters:
        All parameters are stored in ``paremeter.h'', you can change them
        to the values needed. Some paramters are explained below.

        const int stride:
                This stride is an integer, it controls the frequency
                of output. For example, if stride=100 then the program
                would print out data every 100 steps.

        WRITE_SPECTRAL:	
                If this flag is nonzero, then the spectral of bath
                would be written into folder ``check/spectral'' 
                during initialization.

        WRITE_FRIC:
                If this flag is nonzero, then the self energy of bath
                would be written into folder ``check/fric'' during
                initialization.

        WRITE_NOISE:
                If this flag is nonzero, then the noise in omega domain
                would be written into folder ``check/noise'' during
                initialization.

        WRITE_ETA:
                If this flag is nonzero, then the noise in time domain
                would be written into folder ``check/eta'' during
                initialization.

        WRITE_CORRELATION:
                If this flag is nonzero, then the actual correlation of 
                noise in time domain (namely eta) would be calculated 
                and written in folder ``check/correlation'' during
                initialization.

                Note that this would cost a lot of time.

        WRITE_PSI:
                If this flag is nonzero, then the wave function with respect
                to time of electron on all sites would be written in folder
                ``psi'' during simulation.

        WRITE_NORM:
                If this flag is nonzero, then the module of psi with respect
                to time would be written in folder ``check/norm'' during
                simulation.

        WRITE_SPIN:
                If this flag is nonzero, then the spin vector with respect to
                time of each sites would be written in folder ``spin'' during
                simulation.
	
Compile and Run:
	Just type ``make'' to compile it and a program named ``ele'' would
	be generated. Type ``./ele'' to run it. The output would also be
        stored in file ``log''.


Structure of Code:

        parameter.h     auxiliary.h
            |               |
            -----------------
                    |
            -----------------
            |               |
        bath.h          spin.h          chain.h
            |               |              |
            --------------------------------
                            |
                        system.h
                            |
                        init.h
                            |
                        mai.c