introduced norm and metric space

Torsten-Mumme · Torsten-Mumme · commit ceba215e8bee · 2017-12-06T11:57:49.000+01:00
diff --git a/src/main/java/net/itarray/automotion/internal/UIElement.java b/src/main/java/net/itarray/automotion/internal/UIElement.java
@@ -2,7 +2,7 @@
 
 import net.itarray.automotion.internal.geometry.Direction;
 import net.itarray.automotion.internal.geometry.ExtendGiving;
-import net.itarray.automotion.internal.geometry.GroupElement;
+import net.itarray.automotion.internal.geometry.MetricSpace;
 import net.itarray.automotion.internal.geometry.Interval;
 import net.itarray.automotion.internal.geometry.Rectangle;
 import net.itarray.automotion.internal.geometry.Scalar;
@@ -93,7 +93,7 @@ public Scalar getEnd(Direction direction) {
         return direction.end(rectangle);
     }
 
-    public <V extends GroupElement<V>> V getExtend(ExtendGiving<V> direction) {
+    public <V extends MetricSpace<V>> V getExtend(ExtendGiving<V> direction) {
         return direction.extend(rectangle);
     }
 
@@ -149,7 +149,7 @@ public boolean hasEqualBottomOffsetAs(UIElement other) {
         return hasEqualBegin(other, UP);
     }
 
-    private <V extends GroupElement<V>> boolean hasEqualExtendAs(UIElement other, ExtendGiving<V> direction) {
+    private <V extends MetricSpace<V>> boolean hasEqualExtendAs(UIElement other, ExtendGiving<V> direction) {
         return getExtend(direction).equals(other.getExtend(direction));
     }
 
@@ -285,7 +285,7 @@ public void validateSameWidth(UIElement element, Errors errors) {
         validateSameExtend(RIGHT, element, errors);
     }
 
-    public <V extends GroupElement<V>> void validateSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {
+    public <V extends MetricSpace<V>> void validateSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {
         if (!hasEqualExtendAs(element, direction)) {
             errors.add(
                     String.format("Element %s has not the same %s as element %s. %s of %s is %s. %s of element is %s",
@@ -301,7 +301,7 @@ public <V extends GroupElement<V>> void validateSameExtend(ExtendGiving<V> direc
         }
     }
 
-    public <V extends GroupElement<V>> void validateNotSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {
+    public <V extends MetricSpace<V>> void validateNotSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {
         if (hasEqualExtendAs(element, direction)) {
             errors.add(
                     String.format("Element %s has the same %s as element %s. %s of %s is %s. %s of element is %s",
diff --git a/src/main/java/net/itarray/automotion/internal/geometry/ExtendGiving.java b/src/main/java/net/itarray/automotion/internal/geometry/ExtendGiving.java
@@ -1,6 +1,6 @@
 package net.itarray.automotion.internal.geometry;
 
-public interface ExtendGiving<V extends GroupElement<V>> {
+public interface ExtendGiving<V extends MetricSpace<V>> {
     String extendName();
     V begin(Rectangle rectangle);
     V end(Rectangle rectangle);
diff --git a/src/main/java/net/itarray/automotion/internal/geometry/MetricSpace.java b/src/main/java/net/itarray/automotion/internal/geometry/MetricSpace.java
@@ -1,7 +1,8 @@
 package net.itarray.automotion.internal.geometry;
 
-public interface GroupElement<V> {
+public interface MetricSpace<V> {
     V plus(V addend);
     V minus(V subtrahend);
     String toStringWithUnits(String units);
+    Scalar norm();
 }
diff --git a/src/main/java/net/itarray/automotion/internal/geometry/Scalar.java b/src/main/java/net/itarray/automotion/internal/geometry/Scalar.java
@@ -4,7 +4,7 @@
 import net.itarray.automotion.validation.properties.Condition;
 import org.apache.commons.math3.fraction.Fraction;
 
-public class Scalar implements GroupElement<Scalar>, Comparable<Scalar> {
+public class Scalar implements MetricSpace<Scalar>, Comparable<Scalar> {
     private final Fraction fraction;
 
     private Scalar(int value) {
@@ -50,6 +50,10 @@ public int intValue() { // todo: remove usages, this is introspection
         return fraction.intValue();
     }
 
+    public Fraction fractionValue() {
+        return fraction;
+    }
+
     public Scalar plus(int addend) {
         return plus(scalar(addend));
     }
@@ -114,4 +118,8 @@ public Scalar min(Scalar other) {
     public Scalar max(Scalar other) {
         return isGreaterOrEqualTo(other) ? this : other;
     }
+
+    public Scalar norm() {
+        return abs();
+    }
 }
diff --git a/src/main/java/net/itarray/automotion/internal/geometry/Vector.java b/src/main/java/net/itarray/automotion/internal/geometry/Vector.java
@@ -1,8 +1,10 @@
 package net.itarray.automotion.internal.geometry;
 
+import org.apache.commons.math3.fraction.Fraction;
+
 import static net.itarray.automotion.internal.geometry.Scalar.scalar;
 
-public class Vector implements GroupElement<Vector> {
+public class Vector implements MetricSpace<Vector> {
     private final Scalar x;
     private final Scalar y;
 
@@ -56,4 +58,10 @@ public Vector minus(Vector subtrahend) {
     public Vector plus(Vector addend) {
         return new Vector(x.plus(addend.getX()), y.plus(addend.getY()));
     }
+
+    public Scalar norm() {
+        Fraction sumOfCoordinateSquares = x.times(x).plus(y.times(y)).fractionValue();
+        double distance = Math.sqrt(sumOfCoordinateSquares.doubleValue());
+        return scalar(new Fraction(distance));
+    }
 }
diff --git a/src/main/java/net/itarray/automotion/internal/properties/ConditionedExpression.java b/src/main/java/net/itarray/automotion/internal/properties/ConditionedExpression.java
@@ -1,7 +1,7 @@
 package net.itarray.automotion.internal.properties;
 
 import net.itarray.automotion.internal.geometry.Direction;
-import net.itarray.automotion.internal.geometry.GroupElement;
+import net.itarray.automotion.internal.geometry.MetricSpace;
 import net.itarray.automotion.validation.properties.Condition;
 import net.itarray.automotion.validation.properties.Expression;
 
@@ -27,6 +27,6 @@ public String getDescription(Context context, Direction direction) {
                 toBeConditioned.getDescription(context, direction),
                 toBeApplied.getDescription(context, direction),
                 toBeConditioned.getRepeatedDescription(context, direction),
-                (t instanceof GroupElement) ? ((GroupElement) t).toStringWithUnits("px") : t);
+                (t instanceof MetricSpace) ? ((MetricSpace) t).toStringWithUnits("px") : t);
     }
 }
diff --git a/src/main/java/net/itarray/automotion/internal/properties/ElementPropertyExpression.java b/src/main/java/net/itarray/automotion/internal/properties/ElementPropertyExpression.java
@@ -3,7 +3,7 @@
 import net.itarray.automotion.internal.UIElement;
 import net.itarray.automotion.internal.geometry.Direction;
 import net.itarray.automotion.internal.geometry.ExtendGiving;
-import net.itarray.automotion.internal.geometry.GroupElement;
+import net.itarray.automotion.internal.geometry.MetricSpace;
 import net.itarray.automotion.validation.properties.Expression;
 
 import java.util.function.Function;
@@ -18,7 +18,7 @@ private ElementPropertyExpression(UIElement element, Function<UIElement, T> prop
         this.property = new ElementProperty<>(property, descriptionFormat, name);
     }
 
-    public static <V extends GroupElement<V>> ElementPropertyExpression<V> extend(ExtendGiving<V> direction, UIElement element) {
+    public static <V extends MetricSpace<V>> ElementPropertyExpression<V> extend(ExtendGiving<V> direction, UIElement element) {
         return new ElementPropertyExpression<>(element, e -> e.getExtend(direction), direction.extendName() +
                     " of element %s", direction.extendName());
     }
diff --git a/src/test/java/net/itarray/automotion/tests/geometry/ScalarTest.java b/src/test/java/net/itarray/automotion/tests/geometry/ScalarTest.java
@@ -168,5 +168,11 @@ public void satisfies() {
         assertThat(scalar.satisfies(Condition.greaterOrEqualTo(value), context, direction)).isTrue();
         assertThat(scalar.satisfies(Condition.greaterOrEqualTo(value+1), context, direction)).isFalse();
     }
+
+    @Test
+    public void norm() {
+        assertThat(scalar.norm()).isEqualTo(scalar);
+        assertThat(scalar.negated().norm()).isEqualTo(scalar);
+    }
 }
 
diff --git a/src/test/java/net/itarray/automotion/tests/geometry/VectorTest.java b/src/test/java/net/itarray/automotion/tests/geometry/VectorTest.java
@@ -16,8 +16,8 @@ public class VectorTest {
 
     @Before
     public void createVector() {
-        x = scalar(10);
-        y = scalar(23);
+        x = scalar(5);
+        y = scalar(12);
         vector = new Vector(x, y);
     }
 
@@ -55,7 +55,7 @@ public void getYReturnsTheFirstConstructorArgument() {
 
     @Test
     public void toStringWithUnitsAppendsTheUnitsToEachCoordinate() {
-        assertThat(vector.toStringWithUnits("px")).isEqualTo("10px x 23px");
+        assertThat(vector.toStringWithUnits("px")).isEqualTo("5px x 12px");
     }
 
     @Test
@@ -69,4 +69,9 @@ public void plusReturnsAVectorWithValueEqualToTheSumOfValueAndTheAddendValueInBo
         Vector addend = new Vector(2, 3);
         assertThat(vector.plus(addend)).isEqualTo(new Vector(x.plus(2), y.plus(3)));
     }
+
+    @Test
+    public void normReturnsTheEuklideanDistanceToTheOrigin() {
+        assertThat(vector.norm()).isEqualTo(scalar(13));
+    }
 }

Original file line number	Diff line number	Diff line change
`@@ -2,7 +2,7 @@`
`2`	`2`
`3`	`3`	`import net.itarray.automotion.internal.geometry.Direction;`
`4`	`4`	`import net.itarray.automotion.internal.geometry.ExtendGiving;`
`5`		`-import net.itarray.automotion.internal.geometry.GroupElement;`
	`5`	`+import net.itarray.automotion.internal.geometry.MetricSpace;`
`6`	`6`	`import net.itarray.automotion.internal.geometry.Interval;`
`7`	`7`	`import net.itarray.automotion.internal.geometry.Rectangle;`
`8`	`8`	`import net.itarray.automotion.internal.geometry.Scalar;`
`@@ -93,7 +93,7 @@ public Scalar getEnd(Direction direction) {`
`93`	`93`	`return direction.end(rectangle);`
`94`	`94`	`}`
`95`	`95`
`96`		`- public <V extends GroupElement<V>> V getExtend(ExtendGiving<V> direction) {`
	`96`	`+ public <V extends MetricSpace<V>> V getExtend(ExtendGiving<V> direction) {`
`97`	`97`	`return direction.extend(rectangle);`
`98`	`98`	`}`
`99`	`99`
`@@ -149,7 +149,7 @@ public boolean hasEqualBottomOffsetAs(UIElement other) {`
`149`	`149`	`return hasEqualBegin(other, UP);`
`150`	`150`	`}`
`151`	`151`
`152`		`- private <V extends GroupElement<V>> boolean hasEqualExtendAs(UIElement other, ExtendGiving<V> direction) {`
	`152`	`+ private <V extends MetricSpace<V>> boolean hasEqualExtendAs(UIElement other, ExtendGiving<V> direction) {`
`153`	`153`	`return getExtend(direction).equals(other.getExtend(direction));`
`154`	`154`	`}`
`155`	`155`
`@@ -285,7 +285,7 @@ public void validateSameWidth(UIElement element, Errors errors) {`
`285`	`285`	`validateSameExtend(RIGHT, element, errors);`
`286`	`286`	`}`
`287`	`287`
`288`		`- public <V extends GroupElement<V>> void validateSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {`
	`288`	`+ public <V extends MetricSpace<V>> void validateSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {`
`289`	`289`	`if (!hasEqualExtendAs(element, direction)) {`
`290`	`290`	`errors.add(`
`291`	`291`	`String.format("Element %s has not the same %s as element %s. %s of %s is %s. %s of element is %s",`
`@@ -301,7 +301,7 @@ public <V extends GroupElement<V>> void validateSameExtend(ExtendGiving<V> direc`
`301`	`301`	`}`
`302`	`302`	`}`
`303`	`303`
`304`		`- public <V extends GroupElement<V>> void validateNotSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {`
	`304`	`+ public <V extends MetricSpace<V>> void validateNotSameExtend(ExtendGiving<V> direction, UIElement element, Errors errors) {`
`305`	`305`	`if (hasEqualExtendAs(element, direction)) {`
`306`	`306`	`errors.add(`
`307`	`307`	`String.format("Element %s has the same %s as element %s. %s of %s is %s. %s of element is %s",`
Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,8 @@`
`1`	`1`	`package net.itarray.automotion.internal.geometry;`
`2`	`2`
`3`		`-public interface GroupElement<V> {`
	`3`	`+public interface MetricSpace<V> {`
`4`	`4`	`V plus(V addend);`
`5`	`5`	`V minus(V subtrahend);`
`6`	`6`	`String toStringWithUnits(String units);`
	`7`	`+ Scalar norm();`
`7`	`8`	`}`
Original file line number	Diff line number	Diff line change
`@@ -4,7 +4,7 @@`
`4`	`4`	`import net.itarray.automotion.validation.properties.Condition;`
`5`	`5`	`import org.apache.commons.math3.fraction.Fraction;`
`6`	`6`
`7`		`-public class Scalar implements GroupElement<Scalar>, Comparable<Scalar> {`
	`7`	`+public class Scalar implements MetricSpace<Scalar>, Comparable<Scalar> {`
`8`	`8`	`private final Fraction fraction;`
`9`	`9`
`10`	`10`	`private Scalar(int value) {`
`@@ -50,6 +50,10 @@ public int intValue() { // todo: remove usages, this is introspection`
`50`	`50`	`return fraction.intValue();`
`51`	`51`	`}`
`52`	`52`
	`53`	`+ public Fraction fractionValue() {`
	`54`	`+ return fraction;`
	`55`	`+ }`
	`56`	`+`
`53`	`57`	`public Scalar plus(int addend) {`
`54`	`58`	`return plus(scalar(addend));`
`55`	`59`	`}`
`@@ -114,4 +118,8 @@ public Scalar min(Scalar other) {`
`114`	`118`	`public Scalar max(Scalar other) {`
`115`	`119`	`return isGreaterOrEqualTo(other) ? this : other;`
`116`	`120`	`}`
	`121`	`+`
	`122`	`+ public Scalar norm() {`
	`123`	`+ return abs();`
	`124`	`+ }`
`117`	`125`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,7 @@`
`1`	`1`	`package net.itarray.automotion.internal.properties;`
`2`	`2`
`3`	`3`	`import net.itarray.automotion.internal.geometry.Direction;`
`4`		`-import net.itarray.automotion.internal.geometry.GroupElement;`
	`4`	`+import net.itarray.automotion.internal.geometry.MetricSpace;`
`5`	`5`	`import net.itarray.automotion.validation.properties.Condition;`
`6`	`6`	`import net.itarray.automotion.validation.properties.Expression;`
`7`	`7`
`@@ -27,6 +27,6 @@ public String getDescription(Context context, Direction direction) {`
`27`	`27`	`toBeConditioned.getDescription(context, direction),`
`28`	`28`	`toBeApplied.getDescription(context, direction),`
`29`	`29`	`toBeConditioned.getRepeatedDescription(context, direction),`
`30`		`- (t instanceof GroupElement) ? ((GroupElement) t).toStringWithUnits("px") : t);`
	`30`	`+ (t instanceof MetricSpace) ? ((MetricSpace) t).toStringWithUnits("px") : t);`
`31`	`31`	`}`
`32`	`32`	`}`
Original file line number	Diff line number	Diff line change
`@@ -168,5 +168,11 @@ public void satisfies() {`
`168`	`168`	`assertThat(scalar.satisfies(Condition.greaterOrEqualTo(value), context, direction)).isTrue();`
`169`	`169`	`assertThat(scalar.satisfies(Condition.greaterOrEqualTo(value+1), context, direction)).isFalse();`
`170`	`170`	`}`
	`171`	`+`
	`172`	`+ @Test`
	`173`	`+ public void norm() {`
	`174`	`+ assertThat(scalar.norm()).isEqualTo(scalar);`
	`175`	`+ assertThat(scalar.negated().norm()).isEqualTo(scalar);`
	`176`	`+ }`
`171`	`177`	`}`
`172`	`178`
Original file line number	Diff line number	Diff line change
`@@ -16,8 +16,8 @@ public class VectorTest {`
`16`	`16`
`17`	`17`	`@Before`
`18`	`18`	`public void createVector() {`
`19`		`- x = scalar(10);`
`20`		`- y = scalar(23);`
	`19`	`+ x = scalar(5);`
	`20`	`+ y = scalar(12);`
`21`	`21`	`vector = new Vector(x, y);`
`22`	`22`	`}`
`23`	`23`
`@@ -55,7 +55,7 @@ public void getYReturnsTheFirstConstructorArgument() {`
`55`	`55`
`56`	`56`	`@Test`
`57`	`57`	`public void toStringWithUnitsAppendsTheUnitsToEachCoordinate() {`
`58`		`- assertThat(vector.toStringWithUnits("px")).isEqualTo("10px x 23px");`
	`58`	`+ assertThat(vector.toStringWithUnits("px")).isEqualTo("5px x 12px");`
`59`	`59`	`}`
`60`	`60`
`61`	`61`	`@Test`
`@@ -69,4 +69,9 @@ public void plusReturnsAVectorWithValueEqualToTheSumOfValueAndTheAddendValueInBo`
`69`	`69`	`Vector addend = new Vector(2, 3);`
`70`	`70`	`assertThat(vector.plus(addend)).isEqualTo(new Vector(x.plus(2), y.plus(3)));`
`71`	`71`	`}`
	`72`	`+`
	`73`	`+ @Test`
	`74`	`+ public void normReturnsTheEuklideanDistanceToTheOrigin() {`
	`75`	`+ assertThat(vector.norm()).isEqualTo(scalar(13));`
	`76`	`+ }`
`72`	`77`	`}`