fqe.wavefunction.Wavefunction

Wavefunction is the central object for manipulaion in the

fqe.wavefunction.Wavefunction(
    param: Optional[List[List[int]]] = None,
    broken: Optional[Union[List[str], str]] = None
) -> None

OpenFermion-FQE.

Methods

`apply`

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apply(
    hamil: "hamiltonian.Hamiltonian"
) -> "Wavefunction"

Returns a wavefunction subject to application of the Hamiltonian (or more generally, the operator).

Args
hamil (Hamiltonian) - Hamiltonian to be applied

Returns
(Wavefunction) - resulting wave function

`apply_generated_unitary`

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apply_generated_unitary(
    time: float,
    algo: str,
    hamil: "hamiltonian.Hamiltonian",
    accuracy: float = 0.0,
    expansion: int = 30,
    spec_lim: Optional[List[float]] = None
) -> "Wavefunction"

Perform the exponentiation of fermionic algebras to the wavefunction according the method and accuracy.

Args
time (float) - the final time value to evolve to algo (string) - polynomial expansion algorithm to be used hamil (Hamiltonian) - the Hamiltonian used to generate the unitary accuracy (double) - the accuracy to which the system should be evolved expansion (int) - the maximum number of terms in the polynomial expansion spec_lim (List[float]) - spectral range of the Hamiltonian, the length of the list should be 2. Optional.

Args

time (float) - the final time value to evolve to

algo (string) - polynomial expansion algorithm to be used

hamil (Hamiltonian) - the Hamiltonian used to generate the unitary

accuracy (double) - the accuracy to which the system should be evolved

expansion (int) - the maximum number of terms in the polynomial expansion

spec_lim (List[float]) - spectral range of the Hamiltonian, the length of the list should be 2. Optional.

Returns
newwfn (Wavefunction) - a new intialized wavefunction object

`ax_plus_y`

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ax_plus_y(
    sval: complex,
    wfn: "Wavefunction"
) -> None

Perform scale and add of the wavefunction. The result will be stored in self.

Args
sval (complex) - a factor to be multiplied to wfn wfn (Wavefunction) - a wavefunction to be added to self

Args

sval (complex) - a factor to be multiplied to wfn

wfn (Wavefunction) - a wavefunction to be added to self

`conserve_number`

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conserve_number() -> bool

Returns if this wave function conserves the number symmetry

`conserve_spin`

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conserve_spin() -> bool

Returns if this wave function conserves the spin (Sz) symmetry

`expectationValue`

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expectationValue(
    ops: Union['fqe_operator.FqeOperator', 'hamiltonian.Hamiltonian'],
    brawfn: "Wavefunction" = None
) -> Union[complex, numpy.ndarray]

Calculates expectation values given operators

Args
ops (FqeOperator or Hamiltonian) - operator for which the expectation value is computed brawfn (Wavefunction) - bra-side wave function for transition quantity (optional)

Args

ops (FqeOperator or Hamiltonian) - operator for which the expectation value is computed

brawfn (Wavefunction) - bra-side wave function for transition quantity (optional)

Returns
(complex or numpy.ndarray) - resulting expectation value or RDM

`get_coeff`

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get_coeff(
    key: Tuple[int, int]
) -> numpy.ndarray

Retrieve a vector from a configuration in the wavefunction

key indicates wavefunction sector by [num_alpha, num_beta]

Args
key (int, int) - a key identifying the configuration to access vec (int) - an integer indicating which state should be returned

Args

key (int, int) - a key identifying the configuration to access

vec (int) - an integer indicating which state should be returned

Returns
numpy.array(dtype=numpy.complex128)

`max_element`

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max_element() -> complex

Return the largest magnitude value in the wavefunction

`norb`

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norb() -> int

Return the number of orbitals

`norm`

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norm() -> float

Calculate the norm of the wavefuntion

`normalize`

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normalize() -> None

Generte the wavefunction norm and then scale each element by that value.

`print_wfn`

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print_wfn(
    threshold: float = 0.001,
    fmt: str = 'str'
) -> None

Print occupations and coefficients to the screen.

Args

Args
threshhold (float) - only print CI vector values such that :math:`\|c\|` > threshold. fmt (string) - formats print according to argument states (int of list[int]) - an index or indexes indicating which states to print.

threshhold (float) - only print CI vector values such that :math:|c| > threshold.

fmt (string) - formats print according to argument

states (int of list[int]) - an index or indexes indicating which states to print.

`rdm`

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rdm(
    string: str,
    brawfn: Optional['Wavefunction'] = None
) -> Union[complex, numpy.ndarray]

Returns rank-1 RDM. The operator order is specified by string. Note that, if the entire RDM is requested for N-broken wave function, this returns a packed format.

Args
string (str) - character strings that specify the quantity to be computed brawfn (Wavefunction) - bra-side wave function for transition RDM (optional)

Args

string (str) - character strings that specify the quantity to be computed

brawfn (Wavefunction) - bra-side wave function for transition RDM (optional)

Returns
Resulting RDM in numpy.ndarray or element in complex

`read`

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read(
    filename: str,
    path: str = os.getcwd()
) -> None

Initialize a wavefunction from a binary file.

Args
filename (str) - the name of the file to write the wavefunction to. path (str) - the path to save the file. If no path is given then it is saved in the current working directory.

Args

filename (str) - the name of the file to write the wavefunction to.

path (str) - the path to save the file. If no path is given then it is saved in the current working directory.

`save`

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save(
    filename: str,
    path: str = os.getcwd()
) -> None

Save the wavefunction into path/filename.

Args
filename (str) - the name of the file to write the wavefunction to. path (str) - the path to save the file. If no path is given, then it is saved in the current working directory.

Args

filename (str) - the name of the file to write the wavefunction to.

path (str) - the path to save the file. If no path is given, then it is saved in the current working directory.

`scale`

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scale(
    sval: complex
) -> None

Scale each configuration space by the value sval

Args
sval (complex) - value to scale by

`sector`

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sector(
    key
) -> "FqeData"

Return a list of the configuration keys in the wavefunction

`sectors`

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sectors() -> KeysView[Tuple[int, int]]

Return a list of the configuration keys in the wavefunction

`set_wfn`

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set_wfn(
    strategy: str = 'ones',
    raw_data: Optional[Dict[Tuple[int, int], numpy.ndarray]] = None
) -> None

Set the values of the ciwfn based on an argument or data to initalize from.

Args
strategy (string) - an option controlling how the values are set raw_data (numpy.array(dtype=numpy.complex128)) - data to inject into the configuration

Args

strategy (string) - an option controlling how the values are set

raw_data (numpy.array(dtype=numpy.complex128)) - data to inject into the configuration

`time_evolve`

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time_evolve(
    time: float,
    hamil,
    inplace: bool = False
) -> "Wavefunction"

Perform time evolution of the wavefunction given Fermion Operators either as raw operations or wrapped up in a Hamiltonian.

Args
ops (FermionOperators) - FermionOperators which are to be time evolved. time (float) - the duration by which to evolve the operators

Args

ops (FermionOperators) - FermionOperators which are to be time evolved.

time (float) - the duration by which to evolve the operators

Returns
Wavefunction - a wavefunction object that has been time evolved.

`transform`

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transform(
    rotation: numpy.ndarray,
    low: Optional[numpy.ndarray] = None,
    upp: Optional[numpy.ndarray] = None
) -> Tuple[numpy.ndarray, numpy.ndarray, numpy.ndarray, 'Wavefunction']

Transform the wavefunction using the orbtial rotation matrix and return the new wavefunction and the permutation matrix for the unitary transformation. This is an internal code, so performs minimal checking

Args
rotation (numpy.ndarray) - MO rotation matrix, which is unitary low (numpy.ndarray) - L in the LU decomposition (optional) upp (numpy.ndarray) - U in the LU decomposition (optional)

Args

rotation (numpy.ndarray) - MO rotation matrix, which is unitary

low (numpy.ndarray) - L in the LU decomposition (optional)

upp (numpy.ndarray) - U in the LU decomposition (optional)

Returns
(numpy.ndarray, numpy.ndarray, numpy.ndarray, 'Wavefunction') - permutation, L, U, and transformed wavefunction

`add`

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__add__(
    other: "Wavefunction"
) -> "Wavefunction"

Intrinsic addition function to combine two wavefunctions. This acts to iterate through the wavefunctions, combine coefficients of configurations they have in common and add configurations that are unique to each one. The values are all combined into a new wavefunction object

Args
other (wavefunction.Wavefunction) - the second wavefunction to add with the local wavefunction

Returns
wfn (wavefunction.Wavefunction) - a new wavefunction with the values set by adding together values

`getitem`

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__getitem__(
    key: Tuple[int, int]
) -> complex

Element read access to the wave function.

Args
key (Tuple[int, int]) - a pair of strings for alpha and beta

Returns
(complex) - the value of the wave function

`sub`

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__sub__(
    other: "Wavefunction"
) -> "Wavefunction"

Intrinsic subtraction function to combine two wavefunctions. This acts to iterate through the wavefunctions, combine coefficients of configurations they have in common and include configurations that are unique to each one. The values are all combined into a new wavefunction object

Args
other (wavefunction.Wavefunction) - the second wavefunction that will be subtracted from the first wavefunction

Returns
wfn (wavefunction.Wavefunction) - a new wavefunction with the values set by subtracting the wfn from the first