CppAD: A C++ Algorithmic Differentiation Package 20110419
mul.hpp
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00001 /* $Id$ */
00002 # ifndef CPPAD_MUL_INCLUDED
00003 # define CPPAD_MUL_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(MulvvOp) == 1 );
00046                         CPPAD_ASSERT_UNKNOWN( NumArg(MulvvOp) == 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(MulvvOp);
00052                         // make result a variable
00053                         result.id_ = tape_id;
00054                 }
00055                 else if( IdenticalZero(right.value_) )
00056                 {       // result = variable * 0
00057                 }
00058                 else if( IdenticalOne(right.value_) )
00059                 {       // result = variable * 1
00060                         result.make_variable(left.id_, left.taddr_);
00061                 }
00062                 else
00063                 {       // result = variable * parameter
00064                         CPPAD_ASSERT_UNKNOWN( NumRes(MulpvOp) == 1 );
00065                         CPPAD_ASSERT_UNKNOWN( NumArg(MulpvOp) == 2 );
00066 
00067                         // put operand addresses in tape
00068                         size_t p = tape->Rec_.PutPar(right.value_);
00069                         tape->Rec_.PutArg(p, left.taddr_);
00070                         // put operator in the tape
00071                         result.taddr_ = tape->Rec_.PutOp(MulpvOp);
00072                         // make result a variable
00073                         result.id_ = tape_id;
00074                 }
00075         }
00076         else if( var_right )
00077         {       if( IdenticalZero(left.value_) )
00078                 {       // result = 0 * variable
00079                 }
00080                 else if( IdenticalOne(left.value_) )
00081                 {       // result = 1 * variable
00082                         result.make_variable(right.id_, right.taddr_);
00083                 }
00084                 else
00085                 {       // result = parameter * variable
00086                         CPPAD_ASSERT_UNKNOWN( NumRes(MulpvOp) == 1 );
00087                         CPPAD_ASSERT_UNKNOWN( NumArg(MulpvOp) == 2 );
00088 
00089                         // put operand addresses in tape
00090                         size_t p = tape->Rec_.PutPar(left.value_);
00091                         tape->Rec_.PutArg(p, right.taddr_);
00092                         // put operator in the tape
00093                         result.taddr_ = tape->Rec_.PutOp(MulpvOp);
00094                         // make result a variable
00095                         result.id_ = tape_id;
00096                 }
00097         }
00098         return result;
00099 }
00100 
00101 // convert other cases into the case above
00102 CPPAD_FOLD_AD_VALUED_BINARY_OPERATOR(*)
00103 
00104 } // END CppAD namespace
00105 
00106 # endif