Added speed test.

eclipse-january#420

org.eclipse.january.test/src/org/eclipse/january/dataset/SpeedTest.java

@@ -0,0 +1,106 @@
+package org.eclipse.january.dataset;
+
+import static org.junit.Assert.assertTrue;
+
+import java.util.Arrays;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class SpeedTest {
+
+	@Before
+	public void setup() {
+		// We are doing a speed test so we run it once
+		// to make sure libary loading is not timed.
+		multiplyDoubles(Random.rand(10), Math.PI, false);
+		multiplyDoubles(Random.rand(10), Random.rand(10), false);
+		multiplyDoubles(Random.rand(10,10), Random.rand(10), false);
+	}
+
+	@Test
+	public void imulConstant() throws Exception {
+		System.out.println(">> Constant");
+		multiplyDoubles(Random.rand(10000), Math.PI);
+		multiplyDoubles(Random.rand(1000,1000), Math.PI);
+		multiplyDoubles(Random.rand(5000,5000), Math.PI);
+		multiplyDoubles(Random.rand(10,1000,1000), Math.PI);
+		System.out.println(">>>>>");
+	}
+
+	@Test
+	public void imulDataset() throws Exception {
+
+		System.out.println(">> Matrix");
+		multiplyDoubles(Random.rand(10000), Random.rand(10000));
+		multiplyDoubles(Random.rand(1000,1000), Random.rand(1000,1000));
+		multiplyDoubles(Random.rand(5000,5000), Random.rand(5000,5000));
+		multiplyDoubles(Random.rand(10,1000,1000), Random.rand(10,1000,1000));
+		System.out.println(">>>>>");
+	}
+
+	@Test
+	public void imulColumn() throws Exception {
+
+		System.out.println(">> Column");
+		multiplyDoubles(Random.rand(1000,1000), Random.rand(1000));
+		multiplyDoubles(Random.rand(5000,5000), Random.rand(5000));
+		System.out.println(">>>>>");
+	}
+
+	private void multiplyDoubles(final Dataset data, final Object val) {
+		multiplyDoubles(data, val, true);
+	}
+
+	private void multiplyDoubles(final Dataset data, final Object val, boolean realTest) {
+
+		// Using iterator
+		long dt = time(()->data.imultiply(val));
+		if (realTest) {
+			System.out.println("Time imultiply shape "+Arrays.toString(data.getShape())+" was "+dt+"ms");
+		}
+
+		Runnable nr = getNaiveImplementation(data, val);
+		long nt = time(nr);
+		if (realTest) {
+			System.out.println("Time basic loop "+Arrays.toString(data.getShape())+" was "+nt+"ms");
+		}
+
+		// We do not want these tests to be too much slower than simple loop.
+		if (realTest) assertTrue((2*nt)+25 >= dt); // The test is no longer than twice plus a small number constant. 
+		// Adding  a small number constant allows for small differences to be ironed out.
+	}
+
+	private Runnable getNaiveImplementation(Dataset data, Object val) {
+		if (val instanceof Dataset) {
+			Dataset dsVal = (Dataset)val;
+			final double[] da1 = (double[])data.getBuffer();
+			final double[] da2 = (double[])dsVal.getBuffer();
+			if (Arrays.equals(data.getShape(), dsVal.getShape())) {
+				return ()-> {
+					for (int i = 0; i < da1.length; i++) da1[i] *= da2[i];
+				};
+			} else { // Assume columnwise multiply
+				return () -> {
+					for (int i = 0; i < da1.length; i++) {
+						da1[i] *= da2[i%da2.length];
+					}
+				};
+			}
+		} else {
+			double dblValue = (double)val;
+			final double[] da = (double[])data.getBuffer();
+			return ()->{
+				for (int i = 0; i < da.length; i++) da[i] *= dblValue;
+			};
+		}
+
+	}
+
+	private long time(Runnable nr) {
+		long b = System.currentTimeMillis();
+		nr.run();
+		long a = System.currentTimeMillis();
+		return Math.max(1, a-b); // 1 or more for out concerns here.
+	}
+}