QuTiP 4.4.1

The release of QuTiP 4.4.1

Bug Fixes

• Fixed the pickling but that made solver unable to run in parallel on Windows. (Thank lrunze for reporting)
• Removed warning when mesolve fall back on sesolve (by Michael Goerz).
• Fixed dimension check and confusing documentation in random ket (by Yariv Yanay).
• Fixed Qobj isherm not working after using Qobj.permute. (Thank llorz1207 for reporting)
• Correlation functions call now properly handle multiple time dependant functions. (Thank taw181 for reporting)
• Removed mutable default values in mesolve/sesolve (by Michael Goerz)
• Fixed simdiag bug (Thank Croydon-Brixton for reporting)
• Better support of constant QobjEvo. (by Boxi Li)

Improvements

• QobjEvo do not need to start from 0 anymore. (by Eric Giguere)
• Add a quantum object purity function. (by Nathan Shammah and Shahnawaz Ahmed)
• Add step function interpolation for array time-coefficient. (by Boxi Li)

QuTiP 4.4.0

The release of QuTiP 4.4.0

Improvements

• MAJOR FEATURE: Added methods and techniques to the stochastic solvers (by Eric Giguère) which allows to use a much broader set of solvers and much more efficiently.

• MAJOR FEATURE: Optimization of the montecarlo solver (by Eric Giguère). Computation are faster in many cases. Collapse information available to time dependant information.

• Added the QObjEvo class and methods (by Eric Giguère), which is used behind the scenes by the dynamical solvers, making the code more efficient and tidier. More built-in function available to string coefficients. The coefficients can be made from interpolated array with variable timesteps and can obtain state information more easily. Time-dependant collapse operator can have multiple terms.

• New wigner_transform and plot_wigner_sphere function. (by Nithin Ramu).

• ptrace is faster and work on bigger systems, from 15 Qbits to 30 Qbits.

• QIP module: added the possibility for user-defined gates, added the possibility to remove or add gates in any point of an already built circuit, added the molmer_sorensen gate, and fixed some bugs (by Boxi Li).

• Added the quantum Hellinger distance to qutip.metrics (by Wojciech Rzadkowski).

• Implemented possibility of choosing a random seed (by Marek marekyggdrasil).

• Added a code of conduct to Github.

Bug Fixes

• Fixed bug that made QuTiP incompatible with SciPy 1.3.

• quite.cite() is improved.

• Added matplotlib as optional dependency and updated numpy and scipy requirements.

• Fixed matrix generating coherent spin states in qutip.piqs to include complex coefficients.

QuTiP 4.3.1

The release of QuTiP 4.3.1

Improvements

• MAJOR FEATURE: Added the Permutational Invariant Quantum Solver (PIQS) module (by Nathan Shammah and Shahnawaz Ahmed) which allows the simluation of large TLSs ensembles including collective and local Lindblad dissipation. Applications range from superradiance to spin squeezing.

• MAJOR FEATURE: Added a photon scattering module (by Ben Bartlett) which can be used to study scattering in arbitrary driven systems coupled to some configuration of output waveguides.

• Cubic_Spline functions as time-dependent arguments for the collapse operators in mesolve are now allowed.

• Added a faster version of bloch_redfield_tensor, using components from the time-dependent version. About 3x+ faster for secular tensors, and 10x+ faster for non-secular tensors.

• Computing Q.overlap() [inner product] is now ~30x faster.

• Added projector method to Qobj class.

• Added fast projector method, Q.proj().

• Computing matrix elements, Q.matrix_element is now ~10x faster.

• Computing expectation values for ket vectors using expect is now ~10x faster.

• Q.tr() is now faster for small Hilbert space dimensions.

• Unitary operator evolution added to sesolve

• Use OPENMP for tidyup if installed.

Bug Fixes

• Fixed bug that stopped simdiag working for python 3.

• Fixed semidefinite cvxpy Variable and Parameter.

• Fixed iterative lu solve atol keyword issue.

• Fixed unitary op evolution rhs matrix in ssesolve.

• Fixed interpolating function to return zero outside range.

• Fixed dnorm complex casting bug.

• Fixed control.io path checking issue.

• Fixed ENR fock dimension.

• Fixed hard coded options in propagator 'batch' mode

• Fixed bug in trace-norm for non-Hermitian operators.

• Fixed bug related to args not being passed to coherence_function_g2

• Fixed MKL error checking dict key error

QuTiP 4.2.0

Release of QuTiP 4.2.

Improvements

• MAJOR FEATURE: Initial implementation of time-dependent Bloch-Redfield Solver.
• Qobj tidyup is now an order of magnitude faster.
• Time-dependent codegen now generates output NumPy arrays faster.
• Improved calculation for analytic coefficients in coherent states (Sebastian Kramer).
• Input array to correlation FFT method now checked for validity.
• Function-based time-dependent mesolve and sesolve routines now faster.
• Codegen now makes sure that division is done in C, as opposed to Python.
• Can now set different controls for a each timeslot in quantum optimization.
• This allows time-varying controls to be used in pulse optimisation.

Bug Fixes

• rcsolve importing old Odeoptions Class rather than Options.
• Non-int issue in spin Q and Wigner functions.
• Qobj’s should tidyup before determining isherm.
• Fixed time-dependent RHS function loading on Win.
• Fixed several issues with compiling with Cython 0.26.
• Liouvillian superoperators were hard setting isherm=True by default.
• Fixed an issue with the solver safety checks when inputing a list with Python functions as time-dependence.
• Fixed non-int issue in Wigner_cmap.
• MKL solver error handling not working properly.

QuTiP 4.1

QuTiP 4.1

QuTiP-4.0.0

Initial release of QuTiP 4.0