CppAD: A C++ Algorithmic Differentiation Package  20130102
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) 2003-12 Bradley M. Bell
00007 
00008 CppAD is distributed under multiple licenses. This distribution is under
00009 the terms of the 
00010                     Eclipse 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 {
00022      // compute the Base part of this AD object
00023      AD<Base> result;
00024      result.value_  = left.value_ + right.value_;
00025      CPPAD_ASSERT_UNKNOWN( Parameter(result) );
00026 
00027      // check if there is a recording in progress
00028      ADTape<Base>* tape = AD<Base>::tape_ptr();
00029      if( tape == CPPAD_NULL )
00030           return result;
00031      tape_id_t tape_id = tape->id_;
00032 
00033      // tape_id cannot match the default value for tape_id_; i.e., 0
00034      CPPAD_ASSERT_UNKNOWN( tape_id > 0 );
00035      bool var_left  = left.tape_id_  == tape_id;
00036      bool var_right = right.tape_id_ == tape_id;
00037 
00038      if( var_left )
00039      {    if( var_right )
00040           {    // result = variable + variable
00041                CPPAD_ASSERT_UNKNOWN( NumRes(AddvvOp) == 1 );
00042                CPPAD_ASSERT_UNKNOWN( NumArg(AddvvOp) == 2 );
00043 
00044                // put operand addresses in tape
00045                tape->Rec_.PutArg(left.taddr_, right.taddr_);
00046                // put operator in the tape
00047                result.taddr_ = tape->Rec_.PutOp(AddvvOp);
00048                // make result a variable
00049                result.tape_id_ = tape_id;
00050           }
00051           else if( IdenticalZero(right.value_) )
00052           {    // result = variable + 0
00053                result.make_variable(left.tape_id_, left.taddr_);
00054           }
00055           else
00056           {    // result = variable  + parameter
00057                //        = parameter + variable
00058                CPPAD_ASSERT_UNKNOWN( NumRes(AddpvOp) == 1 );
00059                CPPAD_ASSERT_UNKNOWN( NumArg(AddpvOp) == 2 );
00060 
00061                // put operand addresses in tape
00062                addr_t p = tape->Rec_.PutPar(right.value_);
00063                tape->Rec_.PutArg(p, left.taddr_);
00064                // put operator in the tape
00065                result.taddr_ = tape->Rec_.PutOp(AddpvOp);
00066                // make result a variable
00067                result.tape_id_ = tape_id;
00068           }
00069      }
00070      else if( var_right )
00071      {    if( IdenticalZero(left.value_) )
00072           {    // result = 0 + variable
00073                result.make_variable(right.tape_id_, right.taddr_);
00074           }
00075           else
00076           {    // result = parameter + variable
00077                CPPAD_ASSERT_UNKNOWN( NumRes(AddpvOp) == 1 );
00078                CPPAD_ASSERT_UNKNOWN( NumArg(AddpvOp) == 2 );
00079 
00080                // put operand addresses in tape
00081                addr_t p = tape->Rec_.PutPar(left.value_);
00082                tape->Rec_.PutArg(p, right.taddr_);
00083                // put operator in the tape
00084                result.taddr_ = tape->Rec_.PutOp(AddpvOp);
00085                // make result a variable
00086                result.tape_id_ = tape_id;
00087           }
00088      }
00089      return result;
00090 }
00091 
00092 // convert other cases into the case above
00093 CPPAD_FOLD_AD_VALUED_BINARY_OPERATOR(+)
00094 
00095 } // END CppAD namespace
00096 
00097 # endif 
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