code: def multiply(q1, q2):
      """Multiply two quaternions."""
      c = re(q1) * im(q2) + re(q2) * im(q1) + jnp.cross(im(q1), im(q2))
      w = re(q1) * re(q2) - jnp.dot(im(q1), im(q2))
      return jnp.concatenate([c, w], axis=-1)
  
file_path: nerfies/nerfies/quaternion.py
imports: from jax import numpy
  from jax.numpy import linalg
label_desc: Use image node_id 9 for calling a global function with example usage: multiply(q1, q2) and returns: jnp