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Fixed gradient decent

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This commit is contained in:
Ziver Koc 2018-10-01 17:06:53 +02:00
parent cf94310598
commit 98f2219366
2 changed files with 44 additions and 22 deletions
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39
test/zutil/ml/LinearRegressionTest.java
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@ -1,6 +1,7 @@
package zutil.ml;
import org.junit.Test;
import zutil.io.MultiPrintStream;
import zutil.log.LogUtil;
import java.util.logging.Level;
@ -36,8 +37,8 @@ public class LinearRegressionTest {
}
// Does not work
//@Test
public void gradientAscent() {
@Test
public void gradientDescent() {
double[][] x = {
{1.0, 0.1, 0.6, 1.1},
{1.0, 0.2, 0.7, 1.2},
@ -59,14 +60,40 @@ public class LinearRegressionTest {
2
};
double[] resultTheta = LinearRegression.gradientDescent(x, y, theta, 0);
// Alpha zero
assertEquals(0.73482, LinearRegression.calculateCost(x, y, resultTheta), 0.000001);
double[] resultTheta = LinearRegression.gradientDescent(x, y, theta, 0);
System.out.println("Result Theta (alpha = 0):");
System.out.println(MultiPrintStream.dumpToString(resultTheta));
assertArrayEquals(theta, resultTheta, 0.000001);
// Alpha +
resultTheta = LinearRegression.gradientDescent(x, y, theta, 0.1);
System.out.println("Result Theta (alpha = 0.1):");
System.out.println(MultiPrintStream.dumpToString(resultTheta));
assertArrayEquals(
new double[]{-1.31221, -1.98259, 0.36131, 1.70520},
resultTheta, 0.001);
}
@Test
public void gradientAscentIteration() {
double[] theta = LinearRegression.gradientDescentIteration( // one iteration
public void gradientDescentIteration() {
// Zero iterations
double[] theta = LinearRegression.gradientDescentIteration(
/* x */ new double[][]{{1, 5},{1, 2},{1, 4},{1, 5}},
/* y */ new double[]{1, 6, 4, 2},
/* theta */ new double[]{0, 0},
/* alpha */0.0);
assertArrayEquals(new double[]{0.0, 0.0}, theta, 0.000001);
// One iteration
theta = LinearRegression.gradientDescentIteration(
/* x */ new double[][]{{1, 5},{1, 2},{1, 4},{1, 5}},
/* y */ new double[]{1, 6, 4, 2},
/* theta */ new double[]{0, 0},