ExpressionDifferentiator¶

public class ExpressionDifferentiator¶: Object that knows how to differentiate an expression.

Constructors¶

protected ExpressionDifferentiator(DifferentiationEnv adEnv)¶: Constructor.

protected TapList<DiffAssignmentNode>[] adjointDifferentiateAssignedExpression(Tree lhs, boolean needSetDiffLhs, Tree expression, boolean needDiffRhs, TapList<NewBlockGraphNode> toPrecomputes, BoolVector beforeActiv, SymbolTable diffSymbolTable)¶

Adjoint differentiation of expression from assignment lhs:=expression.

Parameters

needSetDiffLhs – when true (general case, e.g. diffLhs is needed upstream) we must generate an instruction that recomputes diffLhs.
needDiffRhs – when true (general case, e.g. diffLhs is active downstream) we must generate the updates of the diff variables of the rhs expression.

Returns

an array (one per replica, in general only one) of lists of future differentiated assignments

protected static int getCost(Tree expression)¶

Run-time cost of expression.

Parameters

Returns

run-time cost.

protected Tree[] tangentDifferentiateAssignedExpression(Tree lhs, Tree expression, TapList<NewBlockGraphNode> toPrecomputes, TapList<DiffAssignmentNode> toPrecomputesDiff, Tree copySrcAssignment, BoolVector beforeActiv, TapPair<TapList<Tree>, TapList<Tree>> primRW, TapPair<TapList<Tree>, TapList<Tree>> diffRW, SymbolTable diffSymbolTable)¶

Tangent differentiation of expression from assignment lhs:=expression.

Returns: an array (one per replica, in general only one) of tangent diff assignment.

protected Tree[] tangentDifferentiatePlainExpression(ToObject<Tree> toPrimalExp, TapList<NewBlockGraphNode> toPrecomputes, TapList<DiffAssignmentNode> toPrecomputesDiff, BoolVector beforeActiv, TapPair<TapList<Tree>, TapList<Tree>> primRW, TapPair<TapList<Tree>, TapList<Tree>> diffRW, SymbolTable diffSymbolTable)¶

Tangent differentiation of a standalone expression (given in toPrimalExp.obj).

Returns: an array (one per replica, in general only one) of tangent diff expression.