Reference a variable on another tape. More...
#include <global.hpp>
Public Member Functions | |
| void | forward (ForwardArgs< Scalar > &args) |
| RefOp copies value from other tape. | |
| void | forward (ForwardArgs< Replay > &args) |
| When replayed it 'resolves' references if applicable. | |
| template<class Type > | |
| void | reverse (ReverseArgs< Type > &args) |
| Reverse mode updates are forbidden until all references are resolved. | |
| void | reverse (ReverseArgs< Replay > &args) |
| Reverse mode updates are allowed in replay mode. | |
 Public Member Functions inherited from TMBad::global::Operator< ninput, noutput > | |
| void | dependencies_updating (Args<> &args, Dependencies &dep) const |
Default implementation of OperatorPure::dependencies_updating() | |
| void * | operator_data () |
| Return operator specific dynamic information (optional) | |
| OperatorPure * | other_fuse (OperatorPure *self, OperatorPure *other) |
| How to fuse this operator (self) with another (other) | |
| void | print (print_config cfg) |
| Print this operator (optional) | |
Additional Inherited Members | |
| Static Public Attributes inherited from TMBad::global::DynamicOperator< 0, 1 > | |
| static const bool | dynamic |
| static const int | max_fuse_depth |
| Static Public Attributes inherited from TMBad::global::Operator< ninput, noutput > | |
| static const bool | add_forward_replay_copy |
| Should this operator replay it self by invoking the copy CTOR ? | |
| static const bool | add_static_identifier |
| Should this operator have a static identifier ? | |
| static const bool | allow_remap |
| Is it safe to remap the inputs of this operator? More... | |
| static const int | dependent_variable |
| Is output of this operator a dependent variable ? | |
| static const bool | dynamic |
| Does this operator require dynamic allocation ? | |
| static const bool | elimination_protected |
| Protect this operator from elimination by the tape optimizer ? | |
| static const bool | have_dependencies |
Have dependencies member been defined ? | |
| static const bool | have_eval |
Does this class have an eval member from which to define forward ? | |
| static const bool | have_forward_incr_reverse_decr |
Have forward_incr and reverse_incr members been defined ? | |
| static const bool | have_forward_mark_reverse_mark |
Have forward_mark and reverse_mark members been defined ? | |
| static const bool | have_forward_reverse |
Have forward and reverse members been defined ? | |
| static const bool | have_increment_decrement |
Have increment and decrement members been defined ? | |
| static const bool | have_input_size_output_size |
Have input_size and output_size members been defined ? | |
| static const bool | implicit_dependencies |
| Does this operator have implicit dependencies? More... | |
| static const int | independent_variable |
| Is output of this operator an independent variable ? | |
| static const bool | is_constant |
| Is this a constant operator ? | |
| static const bool | is_linear |
| Is this a linear operator ? | |
| static const int | max_fuse_depth |
| How many times can this operator be doubled ? | |
| static const int | ninput |
| Number of operator inputs. | |
| static const int | noutput |
| Number of operator outputs. | |
| static const bool | smart_pointer |
| Is this operator a 'smart pointer' (with reference counting) ? | |
| static const bool | updating |
| This operator may update existing variables ? More... | |
Detailed Description
Reference a variable on another tape.
References to other tapes are a handy alternative to independent variables, but there are caveats. One must note that these references are absolute pointers into an other tape's value space. If the other tape is optimized the value indices might get remapped and the absolute references would no longer be valid! It follows that we must have some strict limitations on their use:
- References to other tapes are only allowed to exist temporarily, during tape construction.
- If a child tape has references to a parent tape the parent tape is not complete until all references are 'resolved', i.e. the child tape has been replayed on top of the parent.
- Atomic functions can never be allowed to contain references because atomic function replay does not change whats inside the atomic function. In other words, references would persist during replay and never get resolved.
Definition at line 2408 of file global.hpp.
The documentation for this struct was generated from the following files: