old_contents: """
  Copyright 2013 Steven Diamond
  
  This file is part of CVXPY.
  
  CVXPY is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  
  CVXPY 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 General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with CVXPY.  If not, see <http://www.gnu.org/licenses/>.
  """
  
  from cvxpy.atoms.affine.affine_atom import AffAtom
  from cvxpy.expressions.expression import Expression
  import cvxpy.lin_ops.lin_utils as lu
  import numpy as np
  
  
  def promote(expr, shape):
      expr = Expression.cast_to_const(expr)
      if expr.shape != shape:
          if not expr.is_scalar():
              raise ValueError('Only scalars may be promoted.')
          return Promote(expr, shape)
      else:
          return expr
  
  class Promote(AffAtom):
      """ Promote a scalar expression to a vector/matrix.
  
      Attributes
      ----------
      expr : CVXPY Expression
          The expression to promote.
      shape : tuple
          The shape to promote to.
      """
  
      def __init__(self, expr, shape):
          self.promoted_shape = shape
          super(Promote, self).__init__(expr)
  
      @AffAtom.numpy_numeric
      def numeric(self, values):
          """Promotes the value.
          """
          return np.ones(self.promoted_shape) * values[0]
  
      def shape_from_args(self):
          """Returns the (row, col) shape of the expression.
          """
          return self.promoted_shape
  
      @staticmethod
      def graph_implementation(arg_objs, shape, data=None):
          """Promote scalar to vector/matrix
  
          Parameters
          ----------
          arg_objs : list
              LinExpr for each argument.
          shape : tuple
              The shape of the resulting expression.
          data :
              Additional data required by the atom.
  
          Returns
          -------
          tuple
              (LinOp for objective, list of constraints)
          """
          return (lu.promote(arg_objs[0], shape), [])
  
new_contents: """
  Copyright 2013 Steven Diamond
  
  This file is part of CVXPY.
  
  CVXPY is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  
  CVXPY 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 General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with CVXPY.  If not, see <http://www.gnu.org/licenses/>.
  """
  
  from cvxpy.atoms.affine.affine_atom import AffAtom
  from cvxpy.expressions.constants import Constant
  from cvxpy.expressions.expression import Expression
  import cvxpy.lin_ops.lin_utils as lu
  import numpy as np
  
  
  def promote(expr, shape):
      expr = Expression.cast_to_const(expr)
      if expr.shape != shape:
          if not expr.is_scalar():
              raise ValueError('Only scalars may be promoted.')
          return Promote(expr, shape)
      else:
          return expr
  
  class Promote(AffAtom):
      """ Promote a scalar expression to a vector/matrix.
  
      Attributes
      ----------
      expr : CVXPY Expression
          The expression to promote.
      shape : tuple
          The shape to promote to.
      """
  
      def __init__(self, expr, shape):
          if isinstance(shape, Constant):
              shape = tuple(shape.value.flatten())
          self.promoted_shape = shape
          super(Promote, self).__init__(expr, shape)
  
      @AffAtom.numpy_numeric
      def numeric(self, values):
          """Promotes the value.
          """
          return np.ones(self.promoted_shape) * values[0]
  
      def shape_from_args(self):
          """Returns the (row, col) shape of the expression.
          """
          return self.promoted_shape
  
      @staticmethod
      def graph_implementation(arg_objs, shape, data=None):
          """Promote scalar to vector/matrix
  
          Parameters
          ----------
          arg_objs : list
              LinExpr for each argument.
          shape : tuple
              The shape of the resulting expression.
          data :
              Additional data required by the atom.
  
          Returns
          -------
          tuple
              (LinOp for objective, list of constraints)
          """
          return (lu.promote(arg_objs[0], shape), [])
  
subject: Allow constants to be fed into promote constructor