docstr: Adds a dimension at the end of the `params` array.
docstr_tok: ["Adds","a","dimension","at","the","end","of","the","`","params","`","array","."]
code: def add_dim(self):
      """Adds a dimension at the end of the `params` array."""
      new_params = jnp.expand_dims(self.params, axis=-1)
      # Returns a new object
      return self.__class__(new_params, self.domain)
  
imports: import warnings
  from typing import Callable, TypeVar
  import equinox
  from equinox import tree_equal
  from jax import eval_shape
  from jax import numpy
  from jax import vmap
  from jaxtyping import PyTree
  from jaxdf.core import Field
  from jaxdf.geometry import Domain
label_desc: Use image node_id 2 for calling the OnGrid obj's underlying member method code with example usage: obj.add_dim() and returns: self