[BAEL-2996] Added Colt library example

libraries-2/pom.xml

@@ -54,6 +54,11 @@
             <groupId>org.ejml</groupId>
             <artifactId>ejml-all</artifactId>
             <version>${ejml.version}</version>
+        </dependency>
+		<dependency>
+			<groupId>colt</groupId>
+			<artifactId>colt</artifactId>
+			<version>${colt.version}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
@@ -115,5 +120,6 @@
         <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>
+		<colt.version>1.2.0</colt.version>
 	</properties>
 </project>

libraries-2/src/test/java/com/baeldung/colt/DoubleMatrix2DUniTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.colt;
+
+import cern.colt.matrix.DoubleFactory2D;
+import cern.colt.matrix.DoubleMatrix2D;
+import cern.colt.matrix.linalg.Algebra;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class DoubleMatrix2DUniTest {
+
+    @Test
+    void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        DoubleFactory2D doubleFactory2D = DoubleFactory2D.dense;
+
+        DoubleMatrix2D firstMatrix = doubleFactory2D.make(
+          new double[][] {
+            new double[] {1d, 5d},
+            new double[] {2d, 3d},
+            new double[] {1d ,7d}
+          });
+
+        DoubleMatrix2D secondMatrix = doubleFactory2D.make(
+          new double[][] {
+            new double[] {1d, 2d, 3d, 7d},
+            new double[] {5d, 2d, 8d, 1d}
+          }
+        );
+
+        DoubleMatrix2D expected = doubleFactory2D.make(
+          new double[][] {
+            new double[] {26d, 12d, 43d, 12d},
+            new double[] {17d, 10d, 30d, 17d},
+            new double[] {36d, 16d, 59d, 14d}
+          }
+        );
+
+        Algebra algebra = new Algebra();
+        DoubleMatrix2D actual = algebra.mult(firstMatrix, secondMatrix);
+
+        assertThat(actual).isEqualTo(expected);
+    }
+}