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## MpEvolveBondsThe Matrix Product Toolkit version HEAD-0.7.4.0 (subversion tree rev 855M) Compiled on Feb 25 2008 at 17:11:44 usage: mp-evolve-bonds [options] timestep1 timestep2 .... Allowed options: --help show this help message -H [ --Hamiltonian ] arg operator to use for the Hamiltonian, not an expression! Valid choices: itf, xyz, xxz-u1, xxx-su2 -w [ --wavefunction ] arg wavefunction to apply DMRG (required) -m [ --max-states ] arg Maximum number of states to keep [default 100000] --min-states arg Minimum number of states to keep [default 1] -r [ --trunc ] arg Truncation error cutoff [default 0] -d [ --eigen-cutoff ] arg Cutoff threshold for density matrix eigenvalues (alternative to truncation error) [default -1] --relative truncate relative weights, rather than absolute (for imaginary time evolution you surely want this) -a [ --all ] evolve all bonds at once [PRA 60, 1956 (1999)] --spin arg spin (for xxx,xxz,xyz hamiltonians) --jx arg J_x (for xyz hamiltonian) [default 1.0] --jy arg J_y (for xyz hamiltonian) [default 1.0] --jz arg J_z (for xxz,xyz hamiltonians) [default 1.0] --lambda arg transverse field strength (for itf hamiltonian) [default 1.0]) Unfortunately, the Hamiltonian is specified in a different way to all other tools. There is not yet a way to automatically decompose a Hamiltonian MPO into its bond terms, so instead there are a few Hamiltonian's hard-coded into the program itself. It would be easy to add some more, they are defined in This program does an arbitrary number of sweeps, evolving a subset of bonds by the given timestep on each sweep. The total number of sweeps must be even (if you need an odd number of sweeps, add one more with a timestep of 0). The timesteps can be real or complex. Complex timesteps correspond to imaginary time evolution. By default, The usual options for specifying the truncations all work. By default the truncations are applied absolute, ie. the density matrix weight is There is an option The ## ExampleTo evolve a wavefunction mp-evolve-bonds -w psi -H xxx-su2 -m 100 0.005 0.01 0.005 0 |

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