nd4j-backends/nd4j-api-parent/nd4j-api/src/main/java/org/nd4j/linalg/ops/transforms/Transforms.java
public static INDArray atan2(@NonNull INDArray x, @NonNull INDArray y) {
        return Nd4j.getExecutioner()
                        .execAndReturn(new OldAtan2Op(x, y, Nd4j.createUninitialized(x.shape(), x.ordering())));
    }
public static INDArray atan2(@NonNull INDArray x, @NonNull INDArray y) {
        return Nd4j.getExecutioner()
                        .execAndReturn(new OldAtan2Op(x, y, Nd4j.createUninitialized(x.shape(), x.ordering())));
    }
Atan2 operation, new INDArray instance will be returned
Note the order of x and y parameters is opposite to that of java.lang.Math.atan2

@param x the abscissa coordinate
@param y the ordinate coordinate
@return the theta from point (r, theta) when converting (x,y) from to cartesian to polar coordinates