[BAEL-2996] Added ejml example

libraries-2/pom.xml

@@ -50,6 +50,11 @@
 			<artifactId>picocli</artifactId>
 			<version>${picocli.version}</version>
 		</dependency>
+        <dependency>
+            <groupId>org.ejml</groupId>
+            <artifactId>ejml-all</artifactId>
+            <version>${ejml.version}</version>
+        </dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter</artifactId>
@@ -93,10 +98,10 @@
 			<scope>test</scope>
 		</dependency>
 
-                <dependency>
+        <dependency>
-                    <groupId>edu.uci.ics</groupId>
+            <groupId>edu.uci.ics</groupId>
-                    <artifactId>crawler4j</artifactId>
+            <artifactId>crawler4j</artifactId>
-                    <version>${crawler4j.version}</version>
+            <version>${crawler4j.version}</version>
 		</dependency>
           
 	</dependencies>
@@ -109,5 +114,6 @@
 		<chronicle.map.version>3.17.2</chronicle.map.version>
         <crawler4j.version>4.4.0</crawler4j.version>
 		<spring-boot-starter.version>2.1.4.RELEASE</spring-boot-starter.version>
+		<ejml.version>0.37.1</ejml.version>
 	</properties>
 </project>

libraries-2/src/test/java/com/baeldung/ejml/SimpleMatrixUnitTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.ejml;
+
+import org.ejml.simple.SimpleMatrix;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class SimpleMatrixUnitTest {
+
+    @Test
+    void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        SimpleMatrix firstMatrix = new SimpleMatrix(
+          new double[][] {
+            new double[] {1d, 5d},
+            new double[] {2d, 3d},
+            new double[] {1d ,7d}
+          }
+        );
+
+        SimpleMatrix secondMatrix = new SimpleMatrix(
+          new double[][] {
+            new double[] {1d, 2d, 3d, 7d},
+            new double[] {5d, 2d, 8d, 1d}
+          }
+        );
+
+        SimpleMatrix expected = new SimpleMatrix(
+          new double[][] {
+            new double[] {26d, 12d, 43d, 12d},
+            new double[] {17d, 10d, 30d, 17d},
+            new double[] {36d, 16d, 59d, 14d}
+          }
+        );
+
+        SimpleMatrix actual = firstMatrix.mult(secondMatrix);
+
+        assertThat(actual.numRows()).isEqualTo(expected.numRows());
+        assertThat(actual.numCols()).isEqualTo(expected.numCols());
+        for (int row = 0; row < actual.numRows(); row++) {
+            for (int col = 0; col < actual.numCols(); col++) {
+                assertThat(actual.get(row, col))
+                  .describedAs("Cells at [%d, %d] don't match", row, col)
+                  .isEqualTo(expected.get(row, col));
+            }
+        }
+    }
+}