#
#     This file is part of CasADi.
#
#     CasADi -- A symbolic framework for dynamic optimization.
#     Copyright (C) 2010-2014 Joel Andersson, Joris Gillis, Moritz Diehl,
#                             K.U. Leuven. All rights reserved.
#     Copyright (C) 2011-2014 Greg Horn
#
#     CasADi is free software; you can redistribute it and/or
#     modify it under the terms of the GNU Lesser General Public
#     License as published by the Free Software Foundation; either
#     version 3 of the License, or (at your option) any later version.
#
#     CasADi is distributed in the hope that it will be useful,
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#     Lesser General Public License for more details.
#
#     You should have received a copy of the GNU Lesser General Public
#     License along with CasADi; if not, write to the Free Software
#     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
#
#
from casadi import *
from casadi.tools import *

#! Let's revisit briefly the difference between SX and MX
a = MX.sym("a",2,2)
b = MX.sym("b",2,2)
c = MX.sym("c",2,2)

d = a+b
e = d*c

#! The element-wise addition and multiplication operators appear just as a single node in the MX expression graph
dotdraw(e)

#! We can use expand to expand into subexpressions

f = Function("f", [a,b,c],[e])

g = f.expand('g')

dotdraw(g(*g.sx_in()))

#! There is also a variant to perform expansion immediately on the MX graph
#! The expanded SX graph is hidden inside an SX graph call
dotdraw(matrix_expand(e))

#! An additional features of this variant is that one can choose which expressions remin outside of the expansion scope.
#! In the following we list 'a+b=d' as a node on the boundary of expansion:
dotdraw(matrix_expand(e,[d]))

#! Note how the additions is not expanded, while the multiplication ended up in the expression
