How to determine at runtime if the dl4j/nd4j backend is CPU or GPU?

Question

There is an optimization for dl4j that only works with GPUs: DataTypeUtil.setDTypeForContext(DataBuffer.Type.HALF)

I'd like to only make that call if the backend is a GPU.

In my Maven pom.xml, I've got

<!-- CPU or GPU -->
<nd4j.backend>nd4j-native-platform</nd4j.backend>
<!--<nd4j.backend>nd4j-cuda-8.0-platform</nd4j.backend>-->

And I was looking at ways to read that value from Java, all of which seem clunky. It would be much easier if I could query dl4j or nd4j for "What flavor of backend are we running?" and then make the optimization call based on that.

Edit from answer:

Nd4jBackend.load().let { be->
    println("nd4j Backend: ${be.javaClass.simpleName}")
    if(be.javaClass.simpleName.toLowerCase().contains("gpu")) {
        println("Optimizing for GPU")
        DataTypeUtil.setDTypeForContext(DataBuffer.Type.HALF)
    }
}

Answer 1

See if you can use Nd4j.backend. Printing it with cuda enabled I get:

org.nd4j.linalg.jcublas.JCublasBackend

and without cuda:

org.nd4j.linalg.cpu.nativecpu.CpuBackend