CVXPY
Maximize
  Sum(X * [[2.00 1.00]
 [-2.00 -4.00]], None, False)
Subject To
 14: PnormApprox(X, 2) <= 6.0
Bounds
 X free
End
----------------------------------------
AFTER COMPILATION
Solver 'SCIP' failed. Try another solver, or solve with verbose=True for more information.
----------------------------------------
SCIP
OBJECTIVE
  Sense            : maximize
VARIABLES
  [continuous] <X_0_0>: obj=2, original bounds=[-inf,+inf]
  [continuous] <X_0_1>: obj=1, original bounds=[-inf,+inf]
  [continuous] <X_1_0>: obj=-2, original bounds=[-inf,+inf]
  [continuous] <X_1_1>: obj=-4, original bounds=[-inf,+inf]
CONSTRAINTS
  [nonlinear] <14>: ((<X_0_0>*<X_0_0>+<X_0_1>*<X_0_1>+<X_1_0>*<X_1_0>+<X_1_1>*<X_1_1>))^0.5 <= 6;
END