小编Wil*_*man的帖子

我喜欢在IJulia笔记本上工作,并希望一遍又一遍地在同一行上打印某些流程的状态.

以下面链接中给出的示例为例,我们需要一些输出:

Downloading File FooFile.txt [47%]

并希望避免这样的事情:

 Downloading File FooFile.txt [47%]
 Downloading File FooFile.txt [48%]
 Downloading File FooFile.txt [49%]

在Python的情况下,我在这里找到了答案.

什么是解决方案？

我正在尝试解决一个简单的优化问题，我们想要一个复数值的 Hermitan 矩阵，因为它是可变的（主题是量子力学）

using Convex  #load the optimization solvers
using SCS

# define pauli-y+ projector
# by construction a positive operator valued hermitian matrix
y_plus = [1,im]/sqrt(2)
My0 = y_plus*y_plus'

# define the variable; a 2x2 density matrix
rho = Variable(2, 2)
problem.constraints += [rho == rho']     # hermitian
problem.constraints += [trace(rho) == 1] # unit trace
problem.constraints += [rho in :SDP]     # positive definite


# define the objective
problem = maximize(trace(rho*My0))

# solve
solve!(problem,SCSSolver(verbose=false))

problem.optval

问题是，Julia/JuMP/Convex.jl 都会报错

maximize(trace(rho*My0))

由于跟踪 …