Tools /
## MpiCumulantThis tool calculates the cumulants (moments) of operators. ## note:this tool has been renamed to mp-imomentsMatrix Product Toolkit version HEAD-0.7.4.0 (subversion tree rev 1494) Compiled on May 20 2015 at 02:22:41 Using Boost version 1.41.0 Copyright (c) Ian McCulloch 1999-2015 All Rights Reserved For license conditions email ianmcc@physics.uq.edu.au Documentation see http://physics.uq.edu.au/people/ianmcc/mptoolkit/ usage: mp-icumulant <psi1> <operator> Allowed options: --help show this help message --power arg Calculate expectation value of operator to this power [default 1] -p [ --print ] Print the MPO to standard output -v [ --verbose ] extra debug output (can be used more than once) The wavefunction An alternative, more handy way to give the power of operator is, e.g., ## ExamplesFor example, if you wish to calculate the second moment of Hamiltonian, your command might look like: mp-icumulant psi latttice:"H^2" This would give you a file with entries #degree #real #imag 0 1.6653345369377e-16 1.2924697071141e-26 1 -4.0993636626404 -5.8937963814828e-13 2 -2.138255604645 1.0787815275479e-14 where the degree 2 part is the second order cumulant (variance), the degree 1 part the squared mean of Hamiltonian. As known the definition of variance is ## See also |

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