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fqe.fqe_data_set.FqeDataSet

One of the fundamental data structures in the fqe

Methods

apply

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Applies an operator specified by the tuple of numpy arrays. The result will be returned as a FqeDataSet object. self is unchanged.

apply_individual_nbody

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Apply function with an individual operator represented in arrays, which can handle spin-nonconserving operators and returns the result

apply_inplace

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Applies an operator specified by the tuple of numpy arrays. The result will be kept in-place.

apply_inplace_individual_nbody

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Apply function with an individual operator represented in arrays, which can handle spin-nonconserving operators

ax_plus_y

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Performs :math:y = ax + y with :math:y being self. The result will be kept inplace.

calculate_coeff_with_dvec

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Generate

.. math:: C_I = \sum_J \langle I|a^\dagger_i aj|J \rangle D^J{ij}

calculate_dvec

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Generate, using self.coeff as C_I,

.. math:: D^{J}_{ij} = \sum_I \langle J|a^\dagger_i a_j|I \rangle C_I

calculate_dvec_fixed_j

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Generate, using self.coeff as C_I, for fixed j

.. math:: D^{J}_{ij} = \sum_I \langle J|a^\dagger_i a_j|I \rangle C_I

calculate_dvec_with_coeff

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Generate

.. math:: D^{J}_{ij} = \sum_I \langle J|a^\dagger_i a_j|I \rangle C_I

calculate_dvec_with_coeff_fixed_j

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Generate, for fixed j,

.. math:: D^{J}_{ij} = \sum_I \langle J|a^\dagger_i a_j|I \rangle C_I

calculate_evec

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Generate

.. math:: E^{J}_{klij} = \sum_I \langle J|a^\dagger_k al|I \rangle D^I{ij}

evolve_inplace_individual_nbody

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This code time-evolves a wave function with an individual n-body generator which is spin-nonconserving. It is assumed that :math:T^2 = 0. Using :math:TT = 0 and :math:TT^\dagger is diagonal in the determinant space, one could evaluate as

.. math:: \exp(-i(T+T^\dagger)t) &= 1 + i(T+T^\dagger)t - \frac{1}{2}(TT^\dagger + T^\dagger T)t^2

     - i\frac{1}{6}(TT^\dagger T + T^\dagger TT^\dagger)t^3 + \cdots \\
    &= -1 + \cos(t\sqrt{TT^\dagger}) + \cos(t\sqrt{T^\dagger T})
     - iT\frac{\sin(t\sqrt{T^\dagger T})}{\sqrt{T^\dagger T} }
     - iT^\dagger\frac{\sin(t\sqrt{TT^\dagger})}{\sqrt{TT^\dagger} }

fill

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Fills all of the data to the value specified

rdm1

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Computes 1-particle RDMs. When bra is specified, it computes a transition RDM

rdm12

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Computes 1- and 2-particle RDMs. When bra is specified, it computes a transition RDMs

rdm123

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Computes 1-, 2-, and 3-particle RDMs. When bra is specified, it computes a transition RDMs

rdm1234

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Computes 1-, 2-, 3-, and 4-particle RDMs. When bra is specified, it computes a transition RDMs

scale

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Scales all of the data by the factor specified