ND4S is a free, open-source extension of the Scala programming language operating on the Java Virtual Machine—though it is compatible with both Java and Clojure. ND4S is a scientific computing library for linear algebra and matrix manipulation in a production environment, integrating with Hadoop and Spark to work with distributed GPUs. It supports n-dimensional arrays for JVM-based languages. ND4S has primarily been developed by the group in San Francisco that built Deeplearning4j, led by Adam Gibson. It was created under an Apache Software Foundation license.