我正在尝试解决一个简单的优化问题，我们想要一个复杂值的hermitan矩阵作为它的变量（主题是量子力学）
java.util.concurrent.TimeoutException: Waited for 5 SECONDS, but service was never connected
at android.support.test.rule.ServiceTestRule.waitOnLatch(ServiceTestRule.java:258)
at android.support.test.rule.ServiceTestRule.bindServiceAndWait(ServiceTestRule.java:207)
at android.support.test.rule.ServiceTestRule.startService(ServiceTestRule.java:137)
at com.example.android.testing.ServiceTestRuleSample.LocalServiceTest.testWithBoundService(LocalServiceTest.java:71)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at android.support.test.rule.ServiceTestRule$ServiceStatement.evaluate(ServiceTestRule.java:329)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:54)
at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:240)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1729)
麻烦的是，Julia / JuMP / Convex.jl在谈到
时都会出错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
由于maximize(trace(rho*My0))
的跟踪原则可能很复杂，但我们应确保rho*My0在rho*My0和rho的约束下是真实的。
如何处理这些问题？可能有一个简单的解决方案。最糟糕的情况是，我们可能需要分割实部和虚部。