# Quick guide¶

This section provides a quick guide to find which function does what in The Walrus.

 What you want Corresponding function Numerical hafnian thewalrus.hafnian() Symbolic hafnian thewalrus.reference.hafnian() Hafnian of a matrix with repeated rows and columns thewalrus.hafnian_repeated() Hafnians of all possible reductions of a given matrix thewalrus.hafnian_batched() Hafnian samples of a Gaussian state thewalrus.samples.hafnian_sample_state() Torontonian samples of a Gaussian state thewalrus.samples.torontonian_sample_state() Hafnian samples of a graph thewalrus.samples.hafnian_sample_graph() Torontonian samples of a graph thewalrus.samples.torontonian_sample_graph() All probability amplitudes of a pure Gaussian state thewalrus.quantum.state_vector() All matrix elements of a general Gaussian state thewalrus.quantum.density_matrix() A particular probability amplitude of pure Gaussian state thewalrus.quantum.pure_state_amplitude() A particular matrix element of a general Gaussian state thewalrus.quantum.density_matrix_element() The Fock representation of a Gaussian unitary thewalrus.quantum.fock_tensor()

Note that all the hafnian functions listed above generalize to loop hafnians.