code: public SDVariable var(String name, LongShapeDescriptor shapeDesc) {
          Preconditions.checkNotNull(shapeDesc != null, "Invalid shape: shape may not be null");
          return var(name, shapeDesc, new ZeroInitScheme());
      }
docs: Creates a {@link SDVariable} with the given shape and name<br>
  Any array will be generated with all zeros for the values<br>
  This is a VARIABLE type SDVariable - i.e., must be floating point, and is a trainable parameter. See {@link VariableType} for more details.
  
  @param name      the name of the variable
  @param shapeDesc the shape of the variable
  @return the created variable