Qiskit/qiskit-terra: Qiskit Terra 0.9.0

Changelog Deprecated The gates U and CX are being deprecated in favor of u3 and cx. The gate u0 is being deprecated in favor of using multiple id gates to insert delays (#2664) The decorator requires_qe_access is being deprecated in favor of online_test. The as_dict method of Qobj is deprecated in favor of to_dict. Added A new pulse instruction, Delay. A Delay occupies a pulse channel for a duration of time, blocking other instructions from being inserted in this time. Ability to check for equality of pulse Schedule and Instruction. Added tests for gate_map and reference images for testing plot_gate_map New CountOpsLongest analysis pass to retrieve the number of operations on the longest path of the DAGCircuit. Added sech and sech_deriv pulses in qiskit.pulse.pulse_lib. The option vertical_compression was added to the text drawer and to the QuantumCircuit.draw method. The option allows to control how much room the text circuit drawing takes. The option idle_wires was added to the drawers to control if wires without any operation should be included in the drawing. Introduced a visualization for the Pass Manager. (#2445) New pulse schedule method Schedule.filter to filter by instruction channel, time, and type. (#2597) Decomposition of arbitrary isometries (#2600) Decomposition of diagonal gates (#2600) Decomposition of multiplexed rotation gates (#2600) Decomposition of multiplexed single-qubit unitaries (Option: decompose up to a diagonal gate) (#2600) ZYZ decomposition for single-qubit unitaries (#2600) Gray-Synth and Patel–Markov–Hayes algorithms for synthesis of CNOT-Phase and CNOT-only (linear) circuits (#2457) Added n-qubit unitaries to BasicAer simulator basis gates (#2342) Added a random_circuit function under qiskit.circuit.random (#2553) Added equiv method to Operator and Statevector classes for testing if two objects are equivalent up to global phase (#2910) Added output_name as a transpiler parameter to set the name of output circuits (#2745) Simple expressions of Parameters can now be created via the four basic math operations (+,-,*,/). (#2537) A ParmeterVector class has been added to ease the construction of circuits requiring a large number of parameters. (#2379) dag.draw() method to visualize DAGCircuit objects (#3016) Changed Intervals are now defined by start and stop, rather than begin and end. TimeslotCollections now are sorted by default and have more efficient merges. Pulse samples are now clipped if their norm is between 1 and 1+epsilon. Otherwise an error is raised. Schedule.instructions now returns with time-ordering. More informative errors are now raised if qubit_lo_freq and meas_lo_freq are not supplied to assemble_schedules. pulse.samplers module has now been moved to pulse.pulse_lib.samplers. The number of memory slots required will now be inferred from the supplied schedules if memory_slots is not supplied. All circuit drawers now express most commonly used fractions of PI (#2808). Set default repetition time to be the first available. Pulse commands may now start with capitalized letters. The pylatexenc and pillow requirements are now optional. These are only used by the latex and latex_source circuit visualization backends. To continue using them ensure these are installed. When adding a register to a circuit, an error will now be raised if a register of the same name is already present. Previously, an error would only be raised if the same register was added twice. Qubits and classical bits are not represented as a tuples anymore, but as instances of Qubit and Clbit respectively. The ApplyLayout pass is incorporated in all preset pass managers to delineate a virtual circuit from a physical circuit (#2672) Mapping passes (CXDirection, Swap passes, CheckMap, CheckCnotDirection) now operate on a register-less circuit corresponding to an already embedded physical circuit. (#2672) Replaces LegacySwap by faster, more stable StochasticSwap pass (#2672) Uses level 1 by default as transpiler optimization level (#2672) Change Snapshot signature to match simulator.snapshot (#2592) DAGCircuit.width() formerly returned number of qubits, now returns total number of qubits + classical bits (#2564) Functions assuming the former semantics of DAGCircuit.width() now call DAGCircuit.num_qubits() (#2564) DAGCircuit.num_cbits() renamed to DAGCircuit.num_clbits() (#2564) Changed definition of Cu3Gate to to equivalent to the canonical definition of a controlled U3Gate (#2755) coupling_map now required to validate a backend.configuration() (#2836) The method QuantumCircuit.count_ops now returns an OrderedDict instead of a dict. If layout information is available in the circuit, it will be included to the circuit drawing. This can be removed using the option with_layout=False in the method QuantumCircuit.draw. (#2739) Q-sphere visualization is enhanced and corrected (#2932) Shorter CH gate definition involving only 1 CX (#2837) Now PassManager.draw() (without any argument) will return an in-memory PIL image. Removed The ability to set the Timeslots for a pulse Instruction at initialization. The previously deprecated functions qiksit.visualization.plot_state and qiskit.visualization.iplot_state have been removed. Instead use the specific functions for each plot type (#2325). International documentation of outdated readme etc (#2302) Removed deprecated options in execute, transpile, and assemble. Removed deprecated compiler. Removed deprecated qcvvin tools. Removed deprecated converters qobj_to_circuits and circuits_to_qobj (#2301) The previously deprecated qiskit._util module has been removed. Use qiskit.util instead. (#2329) The logging tools in qiskit.tools.logging are removed. (#2387) The qiskit.qiskiterror module has been removed. Please use qiskit.exceptions instead. (#2399) Removed previously deprecated DAGCircuit methods (#2542) Removed CompositeGate class, in favor of adding Instruction objects directly (#2543) Removed ignore_requires and ignore_preserves options from PassManager (#2565). Fixed Fixes a bug where the CmdDef was getting built without buffers on channels. Fixed bug in Pulse for multiple parameters being added (#2742) Fixed bug in Pulse for CmdDef arguments (#2741) Fixed bug in Operator and SuperOp for initializing from circuit containing gates without an explicit matrix definition (#2723) Possible to decompose SU(4) gate into non-CNOT basis with TwoQubitDecomposer Fixes a bug that removed id gates from circuit. id gates are like a wait command and will never be removed (#2663) Fixed bug in CommutationAnalysis pass affecting conditional gates (#2669) Fixed bug in measure sampling for BasicAer Qasm simulator if a qubit was measured into more than one classical bit (#2735) Correctly serialize complex numbers with a nonzero real part Fixed bug in measure sampling for BasicAer Qasm simulator if only a subset of qubits are measured (#2790) Parameter objects can be serialized and communicated between sub-processes (#2429) Parameterized circuits no longer need to be transpiled individually (#2864