eunjongkim / QuTiP.jl

A Julia wrapper of QuTiP.

QuTiP.jl

This package is under development. Do not use it for anything important

This package is a wrapper of QuTiP using PyCall.

Install

Pkg.add("QuTiP")
# Pkg.checkout("QuTiP") # checkout master branch

Translate Python code into Julia code

Basic usage

Almost all syntax is same as original QuTiP, but some features are different. As PyCall's troubleshooting says, use foo[:bar] and foo[:bar](...) rather than foo.bar and foo.bar(...), respectively.

# python
# quoted from [QuTiP tutorial](http://nbviewer.jupyter.org/github/qutip/qutip-notebooks/blob/master/examples/superop-contract.ipynb)
import numpy as np
import qutip as qt
%matplotlib inline
qt.settings.colorblind_safe = True

q = basis(2,0)
q.dag()

qt.visualization.hinton(qt.identity([2, 3]).unit());

# julia
using QuTiP, PyPlot

q = basis(2,0)
dag(q) # or q'

hinton(qidentity([[2], [3]])[:unit]()) # instead of identity use qidentity

If arguments of QuTiP function contain Julia functions

Julia functions cannot be passed to python as native python functions. So we have to use py"...".

For examples,

# python
# from http://qutip.org/docs/latest/guide/dynamics/dynamics-time.html
def H1_coeff(t, args):
    return 9 * np.exp(-(t / 5.) ** 2)

H = [H0,[H1,H1_coeff]]
output = mesolve(H, psi0, t, c_ops, [ada, sigma_UU, sigma_GG])

# Julia
using PyCall

fnj2py = py"lambda f: lambda t, args: f(t, args)"
H1_coeff(t, args) = 9 * exp(-(t / 5.) ^ 2)

H = [H0,[H1, fnj2py(H1_coeff)]]
output = mesolve(H, psi0, t, c_ops, [ada, sigma_UU, sigma_GG])

convert Qobj to Julia array

To convert Oobj to julia array, use full.

julia> x = basis(2,0)
QuTiP.Quantum(PyObject Quantum object: dims = [[2], [1]], shape = (2, 1), type = ket
Qobj data =
[[ 1.]
 [ 0.]]

julia> full(x)
2×1 Array{Complex{Float64},2}:
 1.0+0.0im
 0.0+0.0im

julia> full(sigmax())
2×2 Array{Complex{Float64},2}:
 0.0+0.0im  1.0+0.0im
 1.0+0.0im  0.0+0.0im

Renamed functions

In order to avoid name conflict, some functions are renamed.
original name --> renamed

• position --> qposition
• identity --> qidentity
• num --> qnum
• squeeze --> qsqueeze

Contributing

I appreciate all kinds of help. Please feel free to open an issue.