Tensorflow JNI development

About

Based on this.

And this one - tensorflow/java/README.md.

How to:

• Install things
• Build libtensorflow.jar, libtensorflow_jni.so
• Install pom.xml and libtensorflow.jar to local maven repo in ~/.m2
• Modify Tensorflow JNI functions
• Create a maven project and use modified JNI

Install

• In Kubuntu
• Get TF 1.15.0 - git or archive
• Install bazel 0.25.2 - see *.deb in releases

Build

cd ~/git/tensorflow-1.15.0
./configure # do not forget CUDA
bazel build -c opt //tensorflow/java:tensorflow //tensorflow/java:libtensorflow_jni //tensorflow/java:pom

Artifacts of interest in bazel-bin/tensorflow/java/:

libtensorflow_jni.so
libtensorflow.jar
pom.xml

• xml and jar are taken care of.
• so will have to be in the library path - set LD_LIBRARY_PATH or PATH or go "java -Djava.library.path"

Install TF to local maven repo

mvn install:install-file -Dfile=bazel-bin/tensorflow/java/libtensorflow.jar -DpomFile=bazel-bin/tensorflow/java/pom.xml

How to uninstall maven local repo - and switch back to official versions form Central:

https://stackoverflow.com/questions/15358851/how-to-remove-jar-file-from-local-maven-repository-which-was-added-with-install

Modify TF JNI

For example, one wants to create a new function in org.tensorflow.TensorFlow package. Then, see:

tensorflow/java/src/main/java/org/tensorflow/
tensorflow/java/src/main/native/

• add native method to tensorflow/java/src/main/java/org/tensorflow/TensorFlow.java
• add to header file tensorflow/java/src/main/native/tensorflow_jni.h
• add to c file tensorflow/java/src/main/native/tensorflow_jni.cc

• rebuild and reinstall to mvn

Java maven project in Eclipse

• Create a new maven project
• Edit pom.xml:

<project>
  ...
  <dependencies>
    ...
    <dependency>
      <groupId>org.tensorflow</groupId>
      <artifactId>libtensorflow</artifactId>
      <version>1.15.0</version>
    </dependency>
    ...
  </dependencies>
  ...
</project>

Basic example code

tfhello.java:

import org.tensorflow.TensorFlow;

public class tfhello{
	public static void main(String[] args){
		System.out.println(TensorFlow.version());
	}
}