add serialization example.

Signed-off-by: Robert Altena <[email protected]>

Author: RobAltena

nd4j-examples/src/main/java/org/nd4j/examples/Nd4jEx16_Serialization.java

@@ -0,0 +1,58 @@
+package org.nd4j.examples;
+
+import org.nd4j.linalg.api.ndarray.INDArray;
+import org.nd4j.linalg.factory.Nd4j;
+
+import java.io.*;
+import java.util.Objects;
+
+/**
+ * Nd4j provides serialization of INDArrays many formats. This example gives some examples for binary and text
+ * serialization.
+ */
+public class Nd4jEx16_Serialization {
+
+    public static void main(String[] args) throws IOException {
+        ClassLoader loader = Nd4jEx16_Serialization.class.getClassLoader();  // used to read files from resources.
+
+        // 1. binary format from stream.
+        INDArray arrWrite = Nd4j.linspace(1,25,25).reshape(5,5);
+        String pathname = "tmp.bin";
+        DataOutputStream sWrite = new DataOutputStream(new FileOutputStream(new File(pathname )));
+        Nd4j.write(arrWrite, sWrite);
+
+        DataInputStream sRead = new DataInputStream(new FileInputStream(new File(pathname )));
+        INDArray arrRead = Nd4j.read(sRead);
+        // We now have our test matrix in arrRead
+        System.out.println("Read from binary format:" );
+        System.out.println(arrRead );
+
+
+        // 2. Read the numpy npy (and npz) formats:
+        File file =  new File( Objects.requireNonNull(loader.getResource("twentyfive.npy")).getFile());
+
+        INDArray x = Nd4j.createFromNpyFile(file); // Nd4j.createFromNpzFile for npz Numpy files.
+        System.out.println();
+        System.out.println("Read from Numpy .npyformat:" );
+        System.out.println(x);
+
+
+        // 3. binary format from file.
+        file =  new File(pathname);
+        Nd4j.saveBinary(arrWrite, file);
+        arrRead = Nd4j.readBinary(file );
+        System.out.println();
+        System.out.println("Read from Numpy .npyformat:" );
+        System.out.println(arrRead);
+
+
+        // 4. read a csv file.
+        file =  new File( Objects.requireNonNull(loader.getResource("twentyfive.csv")).getFile());
+        String Filename = file.getAbsolutePath();
+        arrRead  = Nd4j.readNumpy(Filename, ",");
+        System.out.println();
+        System.out.println("Read from csv format:" );
+        System.out.println(arrRead);
+    }
+
+}

nd4j-examples/src/main/resources/twentyfive.csv

@@ -0,0 +1,5 @@
+1.000000000000000000e+00,2.000000000000000000e+00,3.000000000000000000e+00,4.000000000000000000e+00,5.000000000000000000e+00
+6.000000000000000000e+00,7.000000000000000000e+00,8.000000000000000000e+00,9.000000000000000000e+00,1.000000000000000000e+01
+1.100000000000000000e+01,1.200000000000000000e+01,1.300000000000000000e+01,1.400000000000000000e+01,1.500000000000000000e+01
+1.600000000000000000e+01,1.700000000000000000e+01,1.800000000000000000e+01,1.900000000000000000e+01,2.000000000000000000e+01
+2.100000000000000000e+01,2.200000000000000000e+01,2.300000000000000000e+01,2.400000000000000000e+01,2.500000000000000000e+01