| // Copyright 2008 the V8 project authors. All rights reserved. |
| // Copyright 1996 John Maloney and Mario Wolczko. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 2 of the License, or |
| // (at your option) any later version. |
| // |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| // |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| |
| // This implementation of the DeltaBlue benchmark is derived |
| // from the Smalltalk implementation by John Maloney and Mario |
| // Wolczko. Some parts have been translated directly, whereas |
| // others have been modified more aggresively to make it feel |
| // more like a JavaScript program. |
| |
| |
| var DeltaBlue = new BenchmarkSuite('DeltaBlue', 71104, [ |
| new Benchmark('DeltaBlue', deltaBlue) |
| ]); |
| |
| |
| /** |
| * A JavaScript implementation of the DeltaBlue constrain-solving |
| * algorithm, as described in: |
| * |
| * "The DeltaBlue Algorithm: An Incremental Constraint Hierarchy Solver" |
| * Bjorn N. Freeman-Benson and John Maloney |
| * January 1990 Communications of the ACM, |
| * also available as University of Washington TR 89-08-06. |
| * |
| * Beware: this benchmark is written in a grotesque style where |
| * the constraint model is built by side-effects from constructors. |
| * I've kept it this way to avoid deviating too much from the original |
| * implementation. |
| */ |
| |
| |
| /* --- O b j e c t M o d e l --- */ |
| |
| Object.prototype.inherits = function (shuper) { |
| function Inheriter() { } |
| Inheriter.prototype = shuper.prototype; |
| this.prototype = new Inheriter(); |
| this.superConstructor = shuper; |
| } |
| |
| function OrderedCollection() { |
| this.elms = new Array(); |
| } |
| |
| OrderedCollection.prototype.add = function (elm) { |
| this.elms.push(elm); |
| } |
| |
| OrderedCollection.prototype.at = function (index) { |
| return this.elms[index]; |
| } |
| |
| OrderedCollection.prototype.size = function () { |
| return this.elms.length; |
| } |
| |
| OrderedCollection.prototype.removeFirst = function () { |
| return this.elms.pop(); |
| } |
| |
| OrderedCollection.prototype.remove = function (elm) { |
| var index = 0, skipped = 0; |
| for (var i = 0; i < this.elms.length; i++) { |
| var value = this.elms[i]; |
| if (value != elm) { |
| this.elms[index] = value; |
| index++; |
| } else { |
| skipped++; |
| } |
| } |
| for (var i = 0; i < skipped; i++) |
| this.elms.pop(); |
| } |
| |
| /* --- * |
| * S t r e n g t h |
| * --- */ |
| |
| /** |
| * Strengths are used to measure the relative importance of constraints. |
| * New strengths may be inserted in the strength hierarchy without |
| * disrupting current constraints. Strengths cannot be created outside |
| * this class, so pointer comparison can be used for value comparison. |
| */ |
| function Strength(strengthValue, name) { |
| this.strengthValue = strengthValue; |
| this.name = name; |
| } |
| |
| Strength.stronger = function (s1, s2) { |
| return s1.strengthValue < s2.strengthValue; |
| } |
| |
| Strength.weaker = function (s1, s2) { |
| return s1.strengthValue > s2.strengthValue; |
| } |
| |
| Strength.weakestOf = function (s1, s2) { |
| return this.weaker(s1, s2) ? s1 : s2; |
| } |
| |
| Strength.strongest = function (s1, s2) { |
| return this.stronger(s1, s2) ? s1 : s2; |
| } |
| |
| Strength.prototype.nextWeaker = function () { |
| switch (this.strengthValue) { |
| case 0: return Strength.WEAKEST; |
| case 1: return Strength.WEAK_DEFAULT; |
| case 2: return Strength.NORMAL; |
| case 3: return Strength.STRONG_DEFAULT; |
| case 4: return Strength.PREFERRED; |
| case 5: return Strength.REQUIRED; |
| } |
| } |
| |
| // Strength constants. |
| Strength.REQUIRED = new Strength(0, "required"); |
| Strength.STONG_PREFERRED = new Strength(1, "strongPreferred"); |
| Strength.PREFERRED = new Strength(2, "preferred"); |
| Strength.STRONG_DEFAULT = new Strength(3, "strongDefault"); |
| Strength.NORMAL = new Strength(4, "normal"); |
| Strength.WEAK_DEFAULT = new Strength(5, "weakDefault"); |
| Strength.WEAKEST = new Strength(6, "weakest"); |
| |
| /* --- * |
| * C o n s t r a i n t |
| * --- */ |
| |
| /** |
| * An abstract class representing a system-maintainable relationship |
| * (or "constraint") between a set of variables. A constraint supplies |
| * a strength instance variable; concrete subclasses provide a means |
| * of storing the constrained variables and other information required |
| * to represent a constraint. |
| */ |
| function Constraint(strength) { |
| this.strength = strength; |
| } |
| |
| /** |
| * Activate this constraint and attempt to satisfy it. |
| */ |
| Constraint.prototype.addConstraint = function () { |
| this.addToGraph(); |
| planner.incrementalAdd(this); |
| } |
| |
| /** |
| * Attempt to find a way to enforce this constraint. If successful, |
| * record the solution, perhaps modifying the current dataflow |
| * graph. Answer the constraint that this constraint overrides, if |
| * there is one, or nil, if there isn't. |
| * Assume: I am not already satisfied. |
| */ |
| Constraint.prototype.satisfy = function (mark) { |
| this.chooseMethod(mark); |
| if (!this.isSatisfied()) { |
| if (this.strength == Strength.REQUIRED) |
| alert("Could not satisfy a required constraint!"); |
| return null; |
| } |
| this.markInputs(mark); |
| var out = this.output(); |
| var overridden = out.determinedBy; |
| if (overridden != null) overridden.markUnsatisfied(); |
| out.determinedBy = this; |
| if (!planner.addPropagate(this, mark)) |
| alert("Cycle encountered"); |
| out.mark = mark; |
| return overridden; |
| } |
| |
| Constraint.prototype.destroyConstraint = function () { |
| if (this.isSatisfied()) planner.incrementalRemove(this); |
| else this.removeFromGraph(); |
| } |
| |
| /** |
| * Normal constraints are not input constraints. An input constraint |
| * is one that depends on external state, such as the mouse, the |
| * keybord, a clock, or some arbitraty piece of imperative code. |
| */ |
| Constraint.prototype.isInput = function () { |
| return false; |
| } |
| |
| /* --- * |
| * U n a r y C o n s t r a i n t |
| * --- */ |
| |
| /** |
| * Abstract superclass for constraints having a single possible output |
| * variable. |
| */ |
| function UnaryConstraint(v, strength) { |
| UnaryConstraint.superConstructor.call(this, strength); |
| this.myOutput = v; |
| this.satisfied = false; |
| this.addConstraint(); |
| } |
| |
| UnaryConstraint.inherits(Constraint); |
| |
| /** |
| * Adds this constraint to the constraint graph |
| */ |
| UnaryConstraint.prototype.addToGraph = function () { |
| this.myOutput.addConstraint(this); |
| this.satisfied = false; |
| } |
| |
| /** |
| * Decides if this constraint can be satisfied and records that |
| * decision. |
| */ |
| UnaryConstraint.prototype.chooseMethod = function (mark) { |
| this.satisfied = (this.myOutput.mark != mark) |
| && Strength.stronger(this.strength, this.myOutput.walkStrength); |
| } |
| |
| /** |
| * Returns true if this constraint is satisfied in the current solution. |
| */ |
| UnaryConstraint.prototype.isSatisfied = function () { |
| return this.satisfied; |
| } |
| |
| UnaryConstraint.prototype.markInputs = function (mark) { |
| // has no inputs |
| } |
| |
| /** |
| * Returns the current output variable. |
| */ |
| UnaryConstraint.prototype.output = function () { |
| return this.myOutput; |
| } |
| |
| /** |
| * Calculate the walkabout strength, the stay flag, and, if it is |
| * 'stay', the value for the current output of this constraint. Assume |
| * this constraint is satisfied. |
| */ |
| UnaryConstraint.prototype.recalculate = function () { |
| this.myOutput.walkStrength = this.strength; |
| this.myOutput.stay = !this.isInput(); |
| if (this.myOutput.stay) this.execute(); // Stay optimization |
| } |
| |
| /** |
| * Records that this constraint is unsatisfied |
| */ |
| UnaryConstraint.prototype.markUnsatisfied = function () { |
| this.satisfied = false; |
| } |
| |
| UnaryConstraint.prototype.inputsKnown = function () { |
| return true; |
| } |
| |
| UnaryConstraint.prototype.removeFromGraph = function () { |
| if (this.myOutput != null) this.myOutput.removeConstraint(this); |
| this.satisfied = false; |
| } |
| |
| /* --- * |
| * S t a y C o n s t r a i n t |
| * --- */ |
| |
| /** |
| * Variables that should, with some level of preference, stay the same. |
| * Planners may exploit the fact that instances, if satisfied, will not |
| * change their output during plan execution. This is called "stay |
| * optimization". |
| */ |
| function StayConstraint(v, str) { |
| StayConstraint.superConstructor.call(this, v, str); |
| } |
| |
| StayConstraint.inherits(UnaryConstraint); |
| |
| StayConstraint.prototype.execute = function () { |
| // Stay constraints do nothing |
| } |
| |
| /* --- * |
| * E d i t C o n s t r a i n t |
| * --- */ |
| |
| /** |
| * A unary input constraint used to mark a variable that the client |
| * wishes to change. |
| */ |
| function EditConstraint(v, str) { |
| EditConstraint.superConstructor.call(this, v, str); |
| } |
| |
| EditConstraint.inherits(UnaryConstraint); |
| |
| /** |
| * Edits indicate that a variable is to be changed by imperative code. |
| */ |
| EditConstraint.prototype.isInput = function () { |
| return true; |
| } |
| |
| EditConstraint.prototype.execute = function () { |
| // Edit constraints do nothing |
| } |
| |
| /* --- * |
| * B i n a r y C o n s t r a i n t |
| * --- */ |
| |
| var Direction = new Object(); |
| Direction.NONE = 0; |
| Direction.FORWARD = 1; |
| Direction.BACKWARD = -1; |
| |
| /** |
| * Abstract superclass for constraints having two possible output |
| * variables. |
| */ |
| function BinaryConstraint(var1, var2, strength) { |
| BinaryConstraint.superConstructor.call(this, strength); |
| this.v1 = var1; |
| this.v2 = var2; |
| this.direction = Direction.NONE; |
| this.addConstraint(); |
| } |
| |
| BinaryConstraint.inherits(Constraint); |
| |
| /** |
| * Decides if this constratint can be satisfied and which way it |
| * should flow based on the relative strength of the variables related, |
| * and record that decision. |
| */ |
| BinaryConstraint.prototype.chooseMethod = function (mark) { |
| if (this.v1.mark == mark) { |
| this.direction = (this.v1.mark != mark && Strength.stronger(this.strength, this.v2.walkStrength)) |
| ? Direction.FORWARD |
| : Direction.NONE; |
| } |
| if (this.v2.mark == mark) { |
| this.direction = (this.v1.mark != mark && Strength.stronger(this.strength, this.v1.walkStrength)) |
| ? Direction.BACKWARD |
| : Direction.NONE; |
| } |
| if (Strength.weaker(this.v1.walkStrength, this.v2.walkStrength)) { |
| this.direction = Strength.stronger(this.strength, this.v1.walkStrength) |
| ? Direction.BACKWARD |
| : Direction.NONE; |
| } else { |
| this.direction = Strength.stronger(this.strength, this.v2.walkStrength) |
| ? Direction.FORWARD |
| : Direction.BACKWARD |
| } |
| } |
| |
| /** |
| * Add this constraint to the constraint graph |
| */ |
| BinaryConstraint.prototype.addToGraph = function () { |
| this.v1.addConstraint(this); |
| this.v2.addConstraint(this); |
| this.direction = Direction.NONE; |
| } |
| |
| /** |
| * Answer true if this constraint is satisfied in the current solution. |
| */ |
| BinaryConstraint.prototype.isSatisfied = function () { |
| return this.direction != Direction.NONE; |
| } |
| |
| /** |
| * Mark the input variable with the given mark. |
| */ |
| BinaryConstraint.prototype.markInputs = function (mark) { |
| this.input().mark = mark; |
| } |
| |
| /** |
| * Returns the current input variable |
| */ |
| BinaryConstraint.prototype.input = function () { |
| return (this.direction == Direction.FORWARD) ? this.v1 : this.v2; |
| } |
| |
| /** |
| * Returns the current output variable |
| */ |
| BinaryConstraint.prototype.output = function () { |
| return (this.direction == Direction.FORWARD) ? this.v2 : this.v1; |
| } |
| |
| /** |
| * Calculate the walkabout strength, the stay flag, and, if it is |
| * 'stay', the value for the current output of this |
| * constraint. Assume this constraint is satisfied. |
| */ |
| BinaryConstraint.prototype.recalculate = function () { |
| var ihn = this.input(), out = this.output(); |
| out.walkStrength = Strength.weakestOf(this.strength, ihn.walkStrength); |
| out.stay = ihn.stay; |
| if (out.stay) this.execute(); |
| } |
| |
| /** |
| * Record the fact that this constraint is unsatisfied. |
| */ |
| BinaryConstraint.prototype.markUnsatisfied = function () { |
| this.direction = Direction.NONE; |
| } |
| |
| BinaryConstraint.prototype.inputsKnown = function (mark) { |
| var i = this.input(); |
| return i.mark == mark || i.stay || i.determinedBy == null; |
| } |
| |
| BinaryConstraint.prototype.removeFromGraph = function () { |
| if (this.v1 != null) this.v1.removeConstraint(this); |
| if (this.v2 != null) this.v2.removeConstraint(this); |
| this.direction = Direction.NONE; |
| } |
| |
| /* --- * |
| * S c a l e C o n s t r a i n t |
| * --- */ |
| |
| /** |
| * Relates two variables by the linear scaling relationship: "v2 = |
| * (v1 * scale) + offset". Either v1 or v2 may be changed to maintain |
| * this relationship but the scale factor and offset are considered |
| * read-only. |
| */ |
| function ScaleConstraint(src, scale, offset, dest, strength) { |
| this.direction = Direction.NONE; |
| this.scale = scale; |
| this.offset = offset; |
| ScaleConstraint.superConstructor.call(this, src, dest, strength); |
| } |
| |
| ScaleConstraint.inherits(BinaryConstraint); |
| |
| /** |
| * Adds this constraint to the constraint graph. |
| */ |
| ScaleConstraint.prototype.addToGraph = function () { |
| ScaleConstraint.superConstructor.prototype.addToGraph.call(this); |
| this.scale.addConstraint(this); |
| this.offset.addConstraint(this); |
| } |
| |
| ScaleConstraint.prototype.removeFromGraph = function () { |
| ScaleConstraint.superConstructor.prototype.removeFromGraph.call(this); |
| if (this.scale != null) this.scale.removeConstraint(this); |
| if (this.offset != null) this.offset.removeConstraint(this); |
| } |
| |
| ScaleConstraint.prototype.markInputs = function (mark) { |
| ScaleConstraint.superConstructor.prototype.markInputs.call(this, mark); |
| this.scale.mark = this.offset.mark = mark; |
| } |
| |
| /** |
| * Enforce this constraint. Assume that it is satisfied. |
| */ |
| ScaleConstraint.prototype.execute = function () { |
| if (this.direction == Direction.FORWARD) { |
| this.v2.value = this.v1.value * this.scale.value + this.offset.value; |
| } else { |
| this.v1.value = (this.v2.value - this.offset.value) / this.scale.value; |
| } |
| } |
| |
| /** |
| * Calculate the walkabout strength, the stay flag, and, if it is |
| * 'stay', the value for the current output of this constraint. Assume |
| * this constraint is satisfied. |
| */ |
| ScaleConstraint.prototype.recalculate = function () { |
| var ihn = this.input(), out = this.output(); |
| out.walkStrength = Strength.weakestOf(this.strength, ihn.walkStrength); |
| out.stay = ihn.stay && this.scale.stay && this.offset.stay; |
| if (out.stay) this.execute(); |
| } |
| |
| /* --- * |
| * E q u a l i t y C o n s t r a i n t |
| * --- */ |
| |
| /** |
| * Constrains two variables to have the same value. |
| */ |
| function EqualityConstraint(var1, var2, strength) { |
| EqualityConstraint.superConstructor.call(this, var1, var2, strength); |
| } |
| |
| EqualityConstraint.inherits(BinaryConstraint); |
| |
| /** |
| * Enforce this constraint. Assume that it is satisfied. |
| */ |
| EqualityConstraint.prototype.execute = function () { |
| this.output().value = this.input().value; |
| } |
| |
| /* --- * |
| * V a r i a b l e |
| * --- */ |
| |
| /** |
| * A constrained variable. In addition to its value, it maintain the |
| * structure of the constraint graph, the current dataflow graph, and |
| * various parameters of interest to the DeltaBlue incremental |
| * constraint solver. |
| **/ |
| function Variable(name, initialValue) { |
| this.value = initialValue || 0; |
| this.constraints = new OrderedCollection(); |
| this.determinedBy = null; |
| this.mark = 0; |
| this.walkStrength = Strength.WEAKEST; |
| this.stay = true; |
| this.name = name; |
| } |
| |
| /** |
| * Add the given constraint to the set of all constraints that refer |
| * this variable. |
| */ |
| Variable.prototype.addConstraint = function (c) { |
| this.constraints.add(c); |
| } |
| |
| /** |
| * Removes all traces of c from this variable. |
| */ |
| Variable.prototype.removeConstraint = function (c) { |
| this.constraints.remove(c); |
| if (this.determinedBy == c) this.determinedBy = null; |
| } |
| |
| /* --- * |
| * P l a n n e r |
| * --- */ |
| |
| /** |
| * The DeltaBlue planner |
| */ |
| function Planner() { |
| this.currentMark = 0; |
| } |
| |
| /** |
| * Attempt to satisfy the given constraint and, if successful, |
| * incrementally update the dataflow graph. Details: If satifying |
| * the constraint is successful, it may override a weaker constraint |
| * on its output. The algorithm attempts to resatisfy that |
| * constraint using some other method. This process is repeated |
| * until either a) it reaches a variable that was not previously |
| * determined by any constraint or b) it reaches a constraint that |
| * is too weak to be satisfied using any of its methods. The |
| * variables of constraints that have been processed are marked with |
| * a unique mark value so that we know where we've been. This allows |
| * the algorithm to avoid getting into an infinite loop even if the |
| * constraint graph has an inadvertent cycle. |
| */ |
| Planner.prototype.incrementalAdd = function (c) { |
| var mark = this.newMark(); |
| var overridden = c.satisfy(mark); |
| while (overridden != null) |
| overridden = overridden.satisfy(mark); |
| } |
| |
| /** |
| * Entry point for retracting a constraint. Remove the given |
| * constraint and incrementally update the dataflow graph. |
| * Details: Retracting the given constraint may allow some currently |
| * unsatisfiable downstream constraint to be satisfied. We therefore collect |
| * a list of unsatisfied downstream constraints and attempt to |
| * satisfy each one in turn. This list is traversed by constraint |
| * strength, strongest first, as a heuristic for avoiding |
| * unnecessarily adding and then overriding weak constraints. |
| * Assume: c is satisfied. |
| */ |
| Planner.prototype.incrementalRemove = function (c) { |
| var out = c.output(); |
| c.markUnsatisfied(); |
| c.removeFromGraph(); |
| var unsatisfied = this.removePropagateFrom(out); |
| var strength = Strength.REQUIRED; |
| do { |
| for (var i = 0; i < unsatisfied.size(); i++) { |
| var u = unsatisfied.at(i); |
| if (u.strength == strength) |
| this.incrementalAdd(u); |
| } |
| strength = strength.nextWeaker(); |
| } while (strength != Strength.WEAKEST); |
| } |
| |
| /** |
| * Select a previously unused mark value. |
| */ |
| Planner.prototype.newMark = function () { |
| return ++this.currentMark; |
| } |
| |
| /** |
| * Extract a plan for resatisfaction starting from the given source |
| * constraints, usually a set of input constraints. This method |
| * assumes that stay optimization is desired; the plan will contain |
| * only constraints whose output variables are not stay. Constraints |
| * that do no computation, such as stay and edit constraints, are |
| * not included in the plan. |
| * Details: The outputs of a constraint are marked when it is added |
| * to the plan under construction. A constraint may be appended to |
| * the plan when all its input variables are known. A variable is |
| * known if either a) the variable is marked (indicating that has |
| * been computed by a constraint appearing earlier in the plan), b) |
| * the variable is 'stay' (i.e. it is a constant at plan execution |
| * time), or c) the variable is not determined by any |
| * constraint. The last provision is for past states of history |
| * variables, which are not stay but which are also not computed by |
| * any constraint. |
| * Assume: sources are all satisfied. |
| */ |
| Planner.prototype.makePlan = function (sources) { |
| var mark = this.newMark(); |
| var plan = new Plan(); |
| var todo = sources; |
| while (todo.size() > 0) { |
| var c = todo.removeFirst(); |
| if (c.output().mark != mark && c.inputsKnown(mark)) { |
| plan.addConstraint(c); |
| c.output().mark = mark; |
| this.addConstraintsConsumingTo(c.output(), todo); |
| } |
| } |
| return plan; |
| } |
| |
| /** |
| * Extract a plan for resatisfying starting from the output of the |
| * given constraints, usually a set of input constraints. |
| */ |
| Planner.prototype.extractPlanFromConstraints = function (constraints) { |
| var sources = new OrderedCollection(); |
| for (var i = 0; i < constraints.size(); i++) { |
| var c = constraints.at(i); |
| if (c.isInput() && c.isSatisfied()) |
| // not in plan already and eligible for inclusion |
| sources.add(c); |
| } |
| return this.makePlan(sources); |
| } |
| |
| /** |
| * Recompute the walkabout strengths and stay flags of all variables |
| * downstream of the given constraint and recompute the actual |
| * values of all variables whose stay flag is true. If a cycle is |
| * detected, remove the given constraint and answer |
| * false. Otherwise, answer true. |
| * Details: Cycles are detected when a marked variable is |
| * encountered downstream of the given constraint. The sender is |
| * assumed to have marked the inputs of the given constraint with |
| * the given mark. Thus, encountering a marked node downstream of |
| * the output constraint means that there is a path from the |
| * constraint's output to one of its inputs. |
| */ |
| Planner.prototype.addPropagate = function (c, mark) { |
| var todo = new OrderedCollection(); |
| todo.add(c); |
| while (todo.size() > 0) { |
| var d = todo.removeFirst(); |
| if (d.output().mark == mark) { |
| this.incrementalRemove(c); |
| return false; |
| } |
| d.recalculate(); |
| this.addConstraintsConsumingTo(d.output(), todo); |
| } |
| return true; |
| } |
| |
| |
| /** |
| * Update the walkabout strengths and stay flags of all variables |
| * downstream of the given constraint. Answer a collection of |
| * unsatisfied constraints sorted in order of decreasing strength. |
| */ |
| Planner.prototype.removePropagateFrom = function (out) { |
| out.determinedBy = null; |
| out.walkStrength = Strength.WEAKEST; |
| out.stay = true; |
| var unsatisfied = new OrderedCollection(); |
| var todo = new OrderedCollection(); |
| todo.add(out); |
| while (todo.size() > 0) { |
| var v = todo.removeFirst(); |
| for (var i = 0; i < v.constraints.size(); i++) { |
| var c = v.constraints.at(i); |
| if (!c.isSatisfied()) |
| unsatisfied.add(c); |
| } |
| var determining = v.determinedBy; |
| for (var i = 0; i < v.constraints.size(); i++) { |
| var next = v.constraints.at(i); |
| if (next != determining && next.isSatisfied()) { |
| next.recalculate(); |
| todo.add(next.output()); |
| } |
| } |
| } |
| return unsatisfied; |
| } |
| |
| Planner.prototype.addConstraintsConsumingTo = function (v, coll) { |
| var determining = v.determinedBy; |
| var cc = v.constraints; |
| for (var i = 0; i < cc.size(); i++) { |
| var c = cc.at(i); |
| if (c != determining && c.isSatisfied()) |
| coll.add(c); |
| } |
| } |
| |
| /* --- * |
| * P l a n |
| * --- */ |
| |
| /** |
| * A Plan is an ordered list of constraints to be executed in sequence |
| * to resatisfy all currently satisfiable constraints in the face of |
| * one or more changing inputs. |
| */ |
| function Plan() { |
| this.v = new OrderedCollection(); |
| } |
| |
| Plan.prototype.addConstraint = function (c) { |
| this.v.add(c); |
| } |
| |
| Plan.prototype.size = function () { |
| return this.v.size(); |
| } |
| |
| Plan.prototype.constraintAt = function (index) { |
| return this.v.at(index); |
| } |
| |
| Plan.prototype.execute = function () { |
| for (var i = 0; i < this.size(); i++) { |
| var c = this.constraintAt(i); |
| c.execute(); |
| } |
| } |
| |
| /* --- * |
| * M a i n |
| * --- */ |
| |
| /** |
| * This is the standard DeltaBlue benchmark. A long chain of equality |
| * constraints is constructed with a stay constraint on one end. An |
| * edit constraint is then added to the opposite end and the time is |
| * measured for adding and removing this constraint, and extracting |
| * and executing a constraint satisfaction plan. There are two cases. |
| * In case 1, the added constraint is stronger than the stay |
| * constraint and values must propagate down the entire length of the |
| * chain. In case 2, the added constraint is weaker than the stay |
| * constraint so it cannot be accomodated. The cost in this case is, |
| * of course, very low. Typical situations lie somewhere between these |
| * two extremes. |
| */ |
| function chainTest(n) { |
| planner = new Planner(); |
| var prev = null, first = null, last = null; |
| |
| // Build chain of n equality constraints |
| for (var i = 0; i <= n; i++) { |
| var name = "v" + i; |
| var v = new Variable(name); |
| if (prev != null) |
| new EqualityConstraint(prev, v, Strength.REQUIRED); |
| if (i == 0) first = v; |
| if (i == n) last = v; |
| prev = v; |
| } |
| |
| new StayConstraint(last, Strength.STRONG_DEFAULT); |
| var edit = new EditConstraint(first, Strength.PREFERRED); |
| var edits = new OrderedCollection(); |
| edits.add(edit); |
| var plan = planner.extractPlanFromConstraints(edits); |
| for (var i = 0; i < 100; i++) { |
| first.value = i; |
| plan.execute(); |
| if (last.value != i) |
| alert("Chain test failed."); |
| } |
| } |
| |
| /** |
| * This test constructs a two sets of variables related to each |
| * other by a simple linear transformation (scale and offset). The |
| * time is measured to change a variable on either side of the |
| * mapping and to change the scale and offset factors. |
| */ |
| function projectionTest(n) { |
| planner = new Planner(); |
| var scale = new Variable("scale", 10); |
| var offset = new Variable("offset", 1000); |
| var src = null, dst = null; |
| |
| var dests = new OrderedCollection(); |
| for (var i = 0; i < n; i++) { |
| src = new Variable("src" + i, i); |
| dst = new Variable("dst" + i, i); |
| dests.add(dst); |
| new StayConstraint(src, Strength.NORMAL); |
| new ScaleConstraint(src, scale, offset, dst, Strength.REQUIRED); |
| } |
| |
| change(src, 17); |
| if (dst.value != 1170) alert("Projection 1 failed"); |
| change(dst, 1050); |
| if (src.value != 5) alert("Projection 2 failed"); |
| change(scale, 5); |
| for (var i = 0; i < n - 1; i++) { |
| if (dests.at(i).value != i * 5 + 1000) |
| alert("Projection 3 failed"); |
| } |
| change(offset, 2000); |
| for (var i = 0; i < n - 1; i++) { |
| if (dests.at(i).value != i * 5 + 2000) |
| alert("Projection 4 failed"); |
| } |
| } |
| |
| function change(v, newValue) { |
| var edit = new EditConstraint(v, Strength.PREFERRED); |
| var edits = new OrderedCollection(); |
| edits.add(edit); |
| var plan = planner.extractPlanFromConstraints(edits); |
| for (var i = 0; i < 10; i++) { |
| v.value = newValue; |
| plan.execute(); |
| } |
| edit.destroyConstraint(); |
| } |
| |
| // Global variable holding the current planner. |
| var planner = null; |
| |
| function deltaBlue() { |
| chainTest(100); |
| projectionTest(100); |
| } |