build nd4j for android arm64

nd4jdroid.sh

#for arm64
git clone https://github.com/bytedeco/javacpp-presets.git

export ANDROID_NDK=/path/to/android-ndk/ # e.g. ~/Android/android-ndk-r16b

# build openblas presets for arm64
mvn install --projects .,openblas -Djavacpp.platform=android-arm64 -Djavacpp.platform.root=$ANDROID_NDK -Djavacpp.platform.compiler=$ANDROID_NDK/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64/bin/aarch64-linux-android-g++
#install openblas javacpp-presets arm64 in local maven repository
mvn install:install-file -Dfile=openblas/target/openblas-android-arm64.jar -DgroupID=org.bytedeco.javacpp-presets -DartifactId=openblas -Dversion=0.2.20-1.4.1-SNAPSHOT -Dpackaging=jar -Dclassifier=android-arm64
 
# build openblas presets for arm
#mvn install --projects .,openblas -Djavacpp.platform=android-arm -Djavacpp.platform.root=$ANDROID_NDK -Djavacpp.platform.compiler=$ANDROID_NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++


git clone https://github.com/deeplearning4j/libnd4j
git clone https://github.com/deeplearning4j/nd4j

cd libnd4j
bash buildnativeoperations.sh -platform android-arm64
# bash buildnativeoperations.sh -platform android-arm64

cd ../nd4j

mvn clean install -Djavacpp.platform=android-arm64 -DskipTests -pl :nd4j-api,:nd4j-native -Djavacpp.platform.root=$ANDROID_NDK -Djavacpp.platform.compiler=$ANDROID_NDK/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64/bin/aarch64-linux-android-g++