Adds ConfigurableDataSource data generators for Classification

Classification/Core/src/main/java/org/tribuo/classification/example/CheckerboardDataSource.java

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+/*
+ * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.tribuo.classification.example;
+
+import com.oracle.labs.mlrg.olcut.config.Config;
+import com.oracle.labs.mlrg.olcut.config.PropertyException;
+import org.tribuo.Example;
+import org.tribuo.classification.Label;
+import org.tribuo.impl.ArrayExample;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Creates a data source using a 2d checkerboard of alternating classes.
+ */
+public final class CheckerboardDataSource extends DemoLabelDataSource {
+
+    @Config(description = "The number of squares on each side.")
+    private int numSquares = 5;
+
+    @Config(description = "The minimum feature value.")
+    private double min = 0.0;
+
+    @Config(description = "The maximum feature value.")
+    private double max = 10.0;
+
+    private double range;
+
+    private double tileWidth;
+
+    /**
+     * For OLCUT.
+     */
+    private CheckerboardDataSource() {
+        super();
+    }
+
+    /**
+     * Creates a checkboard with the required number of squares per dimension, where each feature value lies between min and max.
+     *
+     * @param numSamples The number of samples to generate.
+     * @param seed       The RNG seed.
+     * @param numSquares The number of squares.
+     * @param min        The minimum feature value.
+     * @param max        The maximum feature value.
+     */
+    public CheckerboardDataSource(int numSamples, long seed, int numSquares, double min, double max) {
+        super(numSamples, seed);
+        this.numSquares = numSquares;
+        this.min = min;
+        this.max = max;
+        postConfig();
+    }
+
+    /**
+     * Used by the OLCUT configuration system, and should not be called by external code.
+     */
+    @Override
+    public void postConfig() {
+        if (max <= min) {
+            throw new PropertyException("", "min", "min must be strictly less than max, min = " + min + ", max = " + max);
+        }
+        if (numSquares < 2) {
+            throw new PropertyException("", "numSquares", "numSquares must be 2 or greater, found " + numSquares);
+        }
+        range = Math.abs(max - min);
+        tileWidth = range / numSquares;
+        super.postConfig();
+    }
+
+    @Override
+    protected List<Example<Label>> generate() {
+        List<Example<Label>> list = new ArrayList<>();
+
+        for (int i = 0; i < numSamples; i++) {
+            double[] values = new double[2];
+            values[0] = (rng.nextDouble() * range);
+            values[1] = (rng.nextDouble() * range);
+
+            int modX1 = ((int) Math.floor(values[0] / tileWidth)) % 2;
+            int modX2 = ((int) Math.floor(values[1] / tileWidth)) % 2;
+
+            Label label;
+            if (modX1 == modX2) {
+                label = FIRST_CLASS;
+            } else {
+                label = SECOND_CLASS;
+            }
+
+            // Update the minimums after computing the label so we don't have to
+            // deal with tricky negative issues interacting with Math.floor().
+            values[0] += min;
+            values[1] += min;
+
+            list.add(new ArrayExample<>(label, FEATURE_NAMES, values));
+        }
+
+        return list;
+    }
+
+    @Override
+    public String toString() {
+        return "Checkerboard(numSamples=" + numSamples + ",seed=" + seed + ",numSquares=" + numSquares + ",min=" + min + ",max=" + max + ')';
+    }
+}

Classification/Core/src/main/java/org/tribuo/classification/example/ConcentricCirclesDataSource.java

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+/*
+ * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.tribuo.classification.example;
+
+import com.oracle.labs.mlrg.olcut.config.Config;
+import com.oracle.labs.mlrg.olcut.config.PropertyException;
+import org.tribuo.Example;
+import org.tribuo.classification.Label;
+import org.tribuo.impl.ArrayExample;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A data source for two concentric circles, one per class.
+ */
+public final class ConcentricCirclesDataSource extends DemoLabelDataSource {
+
+    @Config(description = "The radius of the outer circle.")
+    private double radius = 2;
+
+    @Config(description = "The proportion of the circle radius that forms class one.")
+    private double classProportion = 0.5;
+
+    /**
+     * For OLCUT.
+     */
+    private ConcentricCirclesDataSource() {
+        super();
+    }
+
+    /**
+     * Constructs a data source for two concentric circles, one per class.
+     *
+     * @param numSamples      The number of samples to generate.
+     * @param seed            The RNG seed.
+     * @param radius          The radius of the outer circle.
+     * @param classProportion The proportion of the circle area that forms class 1.
+     */
+    public ConcentricCirclesDataSource(int numSamples, long seed, double radius, double classProportion) {
+        super(numSamples, seed);
+        this.radius = radius;
+        this.classProportion = classProportion;
+        postConfig();
+    }
+
+    /**
+     * Used by the OLCUT configuration system, and should not be called by external code.
+     */
+    @Override
+    public void postConfig() {
+        if ((classProportion <= 0.0) || (classProportion >= 1.0)) {
+            throw new PropertyException("", "classProportion", "Class proportion must be between zero and one, found " + classProportion);
+        }
+        if (radius <= 0) {
+            throw new PropertyException("", "radius", "Radius must be positive, found " + radius);
+        }
+        super.postConfig();
+    }
+
+    @Override
+    protected List<Example<Label>> generate() {
+        List<Example<Label>> list = new ArrayList<>();
+
+        for (int i = 0; i < numSamples; i++) {
+            double rotation = rng.nextDouble() * 2 * Math.PI;
+            double distance = Math.sqrt(rng.nextDouble()) * radius;
+            double[] values = new double[2];
+            values[0] = distance * Math.cos(rotation);
+            values[1] = distance * Math.sin(rotation);
+
+            double labelDistance = (values[0] * values[0]) + (values[1] * values[1]);
+            Label label;
+            if (labelDistance < classProportion * radius * radius) {
+                label = FIRST_CLASS;
+            } else {
+                label = SECOND_CLASS;
+            }
+
+            list.add(new ArrayExample<>(label, FEATURE_NAMES, values));
+        }
+
+        return list;
+    }
+
+    @Override
+    public String toString() {
+        return "ConcentricCircles(numSamples=" + numSamples + ",seed=" + seed + ",radius=" + radius + ",classProportion=" + classProportion + ")";
+    }
+}