| // Ceres Solver - A fast non-linear least squares minimizer |
| // Copyright 2019 Google Inc. All rights reserved. |
| // http://code.google.com/p/ceres-solver/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
| // * Redistributions of source code must retain the above copyright notice, |
| // this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above copyright notice, |
| // this list of conditions and the following disclaimer in the documentation |
| // and/or other materials provided with the distribution. |
| // * Neither the name of Google Inc. nor the names of its contributors may be |
| // used to endorse or promote products derived from this software without |
| // specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| // POSSIBILITY OF SUCH DAMAGE. |
| // |
| // Author: darius.rueckert@fau.de (Darius Rueckert) |
| |
| #ifndef CERES_PUBLIC_CODEGEN_INTERNAL_EXPRESSION_GRAPH_H_ |
| #define CERES_PUBLIC_CODEGEN_INTERNAL_EXPRESSION_GRAPH_H_ |
| |
| #include <vector> |
| |
| #include "expression.h" |
| |
| namespace ceres { |
| namespace internal { |
| |
| // A directed, acyclic, unconnected graph containing all expressions of a |
| // program. |
| // |
| // The expression graph is stored linear in the expressions_ array. The order is |
| // identical to the execution order. Each expression can have multiple children |
| // and multiple parents. |
| // A is child of B <=> B has A as a parameter <=> B.DirectlyDependsOn(A) |
| // A is parent of B <=> A has B as a parameter <=> A.DirectlyDependsOn(B) |
| class ExpressionGraph { |
| public: |
| // Creates an arithmetic expression of the following form: |
| // <lhs> = <rhs>; |
| // |
| // For example: |
| // CreateArithmeticExpression(PLUS, 5) |
| // will generate: |
| // v_5 = __ + __; |
| // The place holders are then set by the CreateXX functions of Expression. |
| // |
| // If lhs_id == kInvalidExpressionId, then a new lhs_id will be generated and |
| // assigned to the created expression. |
| // Calling this function with a lhs_id that doesn't exist results in an |
| // error. |
| Expression& CreateArithmeticExpression(ExpressionType type, |
| ExpressionId lhs_id); |
| |
| // Control expression don't have a left hand side. |
| // Supported types: IF/ELSE/ENDIF/NOP |
| Expression& CreateControlExpression(ExpressionType type); |
| |
| // Checks if A depends on B. |
| // -> B is a descendant of A |
| bool DependsOn(ExpressionId A, ExpressionId B) const; |
| |
| bool operator==(const ExpressionGraph& other) const; |
| |
| Expression& ExpressionForId(ExpressionId id) { return expressions_[id]; } |
| const Expression& ExpressionForId(ExpressionId id) const { |
| return expressions_[id]; |
| } |
| |
| int Size() const { return expressions_.size(); } |
| |
| // Insert a new expression at "location" into the graph. All expression |
| // after "location" are moved by one element to the back. References to moved |
| // expression are updated. |
| void InsertExpression(ExpressionId location, |
| ExpressionType type, |
| ExpressionId lhs_id, |
| const std::vector<ExpressionId>& arguments, |
| const std::string& name, |
| double value); |
| |
| private: |
| // All Expressions are referenced by an ExpressionId. The ExpressionId is the |
| // index into this array. Each expression has a list of ExpressionId as |
| // arguments. These references form the graph. |
| std::vector<Expression> expressions_; |
| }; |
| |
| // After calling this method, all operations on 'ExpressionRef' objects will be |
| // recorded into an ExpressionGraph. You can obtain this graph by calling |
| // StopRecordingExpressions. |
| // |
| // Performing expression operations before calling StartRecordingExpressions or |
| // calling StartRecodring. twice is an error. |
| void StartRecordingExpressions(); |
| |
| // Stops recording and returns all expressions that have been executed since the |
| // call to StartRecordingExpressions. The internal ExpressionGraph will be |
| // invalidated and a second consecutive call to this method results in an error. |
| ExpressionGraph StopRecordingExpressions(); |
| |
| // Returns a pointer to the active expression tree. |
| // Normal users should not use this functions. |
| ExpressionGraph* GetCurrentExpressionGraph(); |
| |
| } // namespace internal |
| } // namespace ceres |
| |
| #endif // CERES_PUBLIC_CODEGEN_INTERNAL_EXPRESSION_GRAPH_H_ |