title: ValueError: setting an array element with a sequence in CVXPY minimize function
body: <p>I tried to solve a convex problem with cvxpy as below.</p>
  
  <pre><code>        import cvxpy as cp
          import numpy as np
  
          # Problem data.
          Q = np.array([[13, 12, -2], [12, 17, 6], [-2, 6, 12]])
          q = np.array([[-22, -14.5, 13]])
          r = 1
  
          # Construct the problem.
          x = cp.Variable((3,1))
          objective = cp.Minimize(np.dot(np.dot(x.T, Q), x) + np.dot(q, x) + r)
  
          constraints = [0 &lt;= x[0:], x[0:] &lt;= 1]
          prob = cp.Problem(objective, constraints)
  
          # The optimal objective value is returned by `prob.solve()`.
          result = prob.solve()
          # The optimal value for x is stored in `x.value`.
          print(x.value)
          # The optimal Lagrange multiplier for a constraint is stored in
          # `constraint.dual_value`.
          print(constraints[0].dual_value)
  </code></pre>
  
  <p>However, I get this error:</p>
  
  <pre><code>        ValueError: setting an array element with a sequence.
  </code></pre>
  
  <p>I don't know why this error occurs because everything else seems to work.</p>
  
  <p>Edit: Please let me know if the problem statement is needed.</p>