sf.ops.GraphEmbed¶

class
GraphEmbed
(A, mean_photon_per_mode=1.0, make_traceless=False, tol=1e06)[source]¶ Bases:
strawberryfields.ops.Decomposition
Embed a graph into an interferometer setup.
This operation uses the Takagi decomposition to decompose an adjacency matrix into a sequence of squeezers and beamsplitters and rotation gates.
 Parameters
A (array) – an \(N\times N\) complex or real symmetric matrix
mean_photon_per_mode (float) – guarantees that the mean photon number in the pure Gaussian state representing the graph satisfies \(\frac{1}{N}\sum_{i=1}^N sinh(r_{i})^2 ==\) :code:
mean_photon
make_traceless (boolean) – Removes the trace of the input matrix, by performing the transformation \(\tilde{A} = A\mathrm{tr}(A) \I/n\). This may reduce the amount of squeezing needed to encode the graph but will lead to different photon number statistics for events with more than one photon in any mode.
tol (float) – the tolerance used when checking if the input matrix is symmetric: \(AA^T <\) tol
Attributes
Extra dependencies due to parameters that depend on measurements.

measurement_deps
¶ Extra dependencies due to parameters that depend on measurements.
 Returns
dependencies
 Return type
set[RegRef]

ns
= None¶
Methods
apply
(reg, backend, **kwargs)Ask a local backend to execute the operation on the current register state right away.
decompose
(reg, **kwargs)Decompose the operation into elementary operations supported by the backend API.
merge
(other)Merge the operation with another (acting on the exact same set of subsystems).

apply
(reg, backend, **kwargs)¶ Ask a local backend to execute the operation on the current register state right away.
Takes care of parameter evaluations and any pending formal transformations (like dagger) and then calls
Operation._apply()
. Parameters
reg (Sequence[RegRef]) – subsystem(s) the operation is acting on
backend (BaseBackend) – backend to execute the operation
 Returns
the result of self._apply
 Return type
Any

decompose
(reg, **kwargs)¶ Decompose the operation into elementary operations supported by the backend API.
See
strawberryfields.backends.base
.

merge
(other)¶ Merge the operation with another (acting on the exact same set of subsystems).
Note
For subclass overrides: merge may return a newly created object, or self, or other, but it must never modify self or other because the same Operation objects may be also used elsewhere.
 Parameters
other (Operation) – operation to merge this one with
 Returns
other * self. The return value None represents the identity gate (doing nothing).
 Return type
Operation, None
 Raises
MergeFailure – if the two operations cannot be merged
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