Package androidx.constraintlayout.core

Class LinearSystem

java.lang.Object

androidx.constraintlayout.core.LinearSystem

public class LinearSystem
extends java.lang.Object

Represents and solves a system of linear equations.

Field Summary

Fields

Modifier and Type	Field	Description
static long	ARRAY_ROW_CREATION
static boolean	DEBUG
static boolean	FULL_DEBUG
boolean	graphOptimizer
boolean	hasSimpleDefinition
boolean	newgraphOptimizer
static long	OPTIMIZED_ARRAY_ROW_CREATION
static boolean	OPTIMIZED_ENGINE
static boolean	SIMPLIFY_SYNONYMS
static boolean	SKIP_COLUMNS
static Metrics	sMetrics
static boolean	USE_BASIC_SYNONYMS
static boolean	USE_DEPENDENCY_ORDERING
static boolean	USE_SYNONYMS

Constructor Summary

Constructors

Constructor	Description
LinearSystem()

Method Summary

Modifier and Type	Method	Description
void	addCentering(SolverVariable a, SolverVariable b, int m1, float bias, SolverVariable c, SolverVariable d, int m2, int strength)	Add an equation of the form (1 - bias) * (a - b) = bias * (c - d)
void	addCenterPoint(ConstraintWidget widget, ConstraintWidget target, float angle, int radius)	Add the equations constraining a widget center to another widget center, positioned on a circle, following an angle and radius
void	addConstraint(ArrayRow row)	Add the equation to the system
void	addEquality(SolverVariable a, int value)	Add an equation of the form a = value
ArrayRow	addEquality(SolverVariable a, SolverVariable b, int margin, int strength)	Add an equation of the form a = b + margin
void	addGreaterBarrier(SolverVariable a, SolverVariable b, int margin, boolean hasMatchConstraintWidgets)
void	addGreaterThan(SolverVariable a, SolverVariable b, int margin, int strength)	Add an equation of the form a >= b + margin
void	addLowerBarrier(SolverVariable a, SolverVariable b, int margin, boolean hasMatchConstraintWidgets)
void	addLowerThan(SolverVariable a, SolverVariable b, int margin, int strength)	Add an equation of the form a <= b + margin
void	addRatio(SolverVariable a, SolverVariable b, SolverVariable c, SolverVariable d, float ratio, int strength)
void	addSynonym(SolverVariable a, SolverVariable b, int margin)
SolverVariable	createErrorVariable(int strength, java.lang.String prefix)
SolverVariable	createExtraVariable()
SolverVariable	createObjectVariable(java.lang.Object anchor)
ArrayRow	createRow()
static ArrayRow	createRowDimensionPercent(LinearSystem linearSystem, SolverVariable variableA, SolverVariable variableC, float percent)	Create a constraint to express A = C * percent
SolverVariable	createSlackVariable()
void	displayReadableRows()
void	displayVariablesReadableRows()
void	fillMetrics(Metrics metrics)
Cache	getCache()
int	getMemoryUsed()
static Metrics	getMetrics()
int	getNumEquations()
int	getNumVariables()
int	getObjectVariableValue(java.lang.Object object)
void	minimize()	Minimize the current goal of the system.
void	removeRow(ArrayRow row)
void	reset()	Reset the LinearSystem object so that it can be reused.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FULL_DEBUG

public static final boolean FULL_DEBUG

See Also:

Constant Field Values

DEBUG

public static final boolean DEBUG

See Also:

Constant Field Values

USE_DEPENDENCY_ORDERING

public static boolean USE_DEPENDENCY_ORDERING

USE_BASIC_SYNONYMS

public static boolean USE_BASIC_SYNONYMS

SIMPLIFY_SYNONYMS

public static boolean SIMPLIFY_SYNONYMS

USE_SYNONYMS

public static boolean USE_SYNONYMS

SKIP_COLUMNS

public static boolean SKIP_COLUMNS

OPTIMIZED_ENGINE

public static boolean OPTIMIZED_ENGINE

hasSimpleDefinition

public boolean hasSimpleDefinition

graphOptimizer

public boolean graphOptimizer

newgraphOptimizer

public boolean newgraphOptimizer

sMetrics

public static Metrics sMetrics

ARRAY_ROW_CREATION

public static long ARRAY_ROW_CREATION

OPTIMIZED_ARRAY_ROW_CREATION

public static long OPTIMIZED_ARRAY_ROW_CREATION

Constructor Detail

LinearSystem

public LinearSystem()

Method Detail

fillMetrics

public void fillMetrics(Metrics metrics)

getMetrics

public static Metrics getMetrics()

reset

public void reset()

Reset the LinearSystem object so that it can be reused.

createObjectVariable

public SolverVariable createObjectVariable(java.lang.Object anchor)

createRow

public ArrayRow createRow()

createSlackVariable

public SolverVariable createSlackVariable()

createExtraVariable

public SolverVariable createExtraVariable()

createErrorVariable

public SolverVariable createErrorVariable(int strength,
                                          java.lang.String prefix)

getObjectVariableValue

public int getObjectVariableValue(java.lang.Object object)

minimize

public void minimize()
              throws java.lang.Exception

Minimize the current goal of the system.

Throws:

java.lang.Exception

addConstraint

public void addConstraint(ArrayRow row)

Add the equation to the system

Parameters:

row - the equation we want to add expressed as a system row.

removeRow

public void removeRow(ArrayRow row)

displayReadableRows

public void displayReadableRows()

displayVariablesReadableRows

public void displayVariablesReadableRows()

getMemoryUsed

public int getMemoryUsed()

getNumEquations

public int getNumEquations()

getNumVariables

public int getNumVariables()

getCache

public Cache getCache()

addGreaterThan

public void addGreaterThan(SolverVariable a,
                           SolverVariable b,
                           int margin,
                           int strength)

Add an equation of the form a >= b + margin

Parameters:

a - variable a

b - variable b

margin - margin

strength - strength used

addGreaterBarrier

public void addGreaterBarrier(SolverVariable a,
                              SolverVariable b,
                              int margin,
                              boolean hasMatchConstraintWidgets)

addLowerThan

public void addLowerThan(SolverVariable a,
                         SolverVariable b,
                         int margin,
                         int strength)

Add an equation of the form a <= b + margin

Parameters:

a - variable a

b - variable b

margin - margin

strength - strength used

addLowerBarrier

public void addLowerBarrier(SolverVariable a,
                            SolverVariable b,
                            int margin,
                            boolean hasMatchConstraintWidgets)

addCentering

public void addCentering(SolverVariable a,
                         SolverVariable b,
                         int m1,
                         float bias,
                         SolverVariable c,
                         SolverVariable d,
                         int m2,
                         int strength)

Add an equation of the form (1 - bias) * (a - b) = bias * (c - d)

Parameters:

a - variable a

b - variable b

m1 - margin 1

bias - bias between ab - cd

c - variable c

d - variable d

m2 - margin 2

strength - strength used

addRatio

public void addRatio(SolverVariable a,
                     SolverVariable b,
                     SolverVariable c,
                     SolverVariable d,
                     float ratio,
                     int strength)

addSynonym

public void addSynonym(SolverVariable a,
                       SolverVariable b,
                       int margin)

addEquality

public ArrayRow addEquality(SolverVariable a,
                            SolverVariable b,
                            int margin,
                            int strength)

Add an equation of the form a = b + margin

Parameters:

a - variable a

b - variable b

margin - margin used

strength - strength used

addEquality

public void addEquality(SolverVariable a,
                        int value)

Add an equation of the form a = value

Parameters:

a - variable a

value - the value we set

createRowDimensionPercent

public static ArrayRow createRowDimensionPercent(LinearSystem linearSystem,
                                                 SolverVariable variableA,
                                                 SolverVariable variableC,
                                                 float percent)

Create a constraint to express A = C * percent

Parameters:

linearSystem - the system we create the row on

variableA - variable a

variableC - variable c

percent - the percent used

Returns:

the created row

addCenterPoint

public void addCenterPoint(ConstraintWidget widget,
                           ConstraintWidget target,
                           float angle,
                           int radius)

Add the equations constraining a widget center to another widget center, positioned on a circle, following an angle and radius

Parameters:

angle - from 0 to 360

radius - the distance between the two centers