CppAD: A C++ Algorithmic Differentiation Package 20110419
add.hpp
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00001 /* $Id$ */
00002 # ifndef CPPAD_ADD_INCLUDED
00003 # define CPPAD_ADD_INCLUDED
00004 
00005 /* --------------------------------------------------------------------------
00006 CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-11 Bradley M. Bell
00007 
00008 CppAD is distributed under multiple licenses. This distribution is under
00009 the terms of the 
00010                     Common Public License Version 1.0.
00011 
00012 A copy of this license is included in the COPYING file of this distribution.
00013 Please visit http://www.coin-or.org/CppAD/ for information on other licenses.
00014 -------------------------------------------------------------------------- */
00015 
00016 //  BEGIN CppAD namespace
00017 namespace CppAD {
00018 
00019 template <class Base>
00020 AD<Base> operator + (const AD<Base> &left , const AD<Base> &right)
00021 {       ADTape<Base> *tape = AD<Base>::tape_ptr();
00022         size_t tape_id = 0;
00023         if( tape != CPPAD_NULL )
00024                 tape_id = tape->id_;
00025 
00026         // id_ setting for parameters cannot match 0
00027         bool var_left  = left.id_  == tape_id;
00028         bool var_right = right.id_ == tape_id;
00029         CPPAD_ASSERT_KNOWN(
00030                 Parameter(left) || var_left ,
00031                 "+: left operand is a variable for a different thread"
00032         );
00033         CPPAD_ASSERT_KNOWN(
00034                 Parameter(right) || var_right ,
00035                 "+: right operand is a variable for a different thread"
00036         );
00037 
00038         AD<Base> result;
00039         result.value_  = left.value_ + right.value_;
00040         CPPAD_ASSERT_UNKNOWN( Parameter(result) );
00041 
00042         if( var_left )
00043         {       if( var_right )
00044                 {       // result = variable + variable
00045                         CPPAD_ASSERT_UNKNOWN( NumRes(AddvvOp) == 1 );
00046                         CPPAD_ASSERT_UNKNOWN( NumArg(AddvvOp) == 2 );
00047 
00048                         // put operand addresses in tape
00049                         tape->Rec_.PutArg(left.taddr_, right.taddr_);
00050                         // put operator in the tape
00051                         result.taddr_ = tape->Rec_.PutOp(AddvvOp);
00052                         // make result a variable
00053                         result.id_ = tape_id;
00054                 }
00055                 else if( IdenticalZero(right.value_) )
00056                 {       // result = variable + 0
00057                         result.make_variable(left.id_, left.taddr_);
00058                 }
00059                 else
00060                 {       // result = variable  + parameter
00061                         //        = parameter + variable
00062                         CPPAD_ASSERT_UNKNOWN( NumRes(AddpvOp) == 1 );
00063                         CPPAD_ASSERT_UNKNOWN( NumArg(AddpvOp) == 2 );
00064 
00065                         // put operand addresses in tape
00066                         size_t p = tape->Rec_.PutPar(right.value_);
00067                         tape->Rec_.PutArg(p, left.taddr_);
00068                         // put operator in the tape
00069                         result.taddr_ = tape->Rec_.PutOp(AddpvOp);
00070                         // make result a variable
00071                         result.id_ = tape_id;
00072                 }
00073         }
00074         else if( var_right )
00075         {       if( IdenticalZero(left.value_) )
00076                 {       // result = 0 + variable
00077                         result.make_variable(right.id_, right.taddr_);
00078                 }
00079                 else
00080                 {       // result = parameter + variable
00081                         CPPAD_ASSERT_UNKNOWN( NumRes(AddpvOp) == 1 );
00082                         CPPAD_ASSERT_UNKNOWN( NumArg(AddpvOp) == 2 );
00083 
00084                         // put operand addresses in tape
00085                         size_t p = tape->Rec_.PutPar(left.value_);
00086                         tape->Rec_.PutArg(p, right.taddr_);
00087                         // put operator in the tape
00088                         result.taddr_ = tape->Rec_.PutOp(AddpvOp);
00089                         // make result a variable
00090                         result.id_ = tape_id;
00091                 }
00092         }
00093         return result;
00094 }
00095 
00096 // convert other cases into the case above
00097 CPPAD_FOLD_AD_VALUED_BINARY_OPERATOR(+)
00098 
00099 } // END CppAD namespace
00100 
00101 # endif