code: def exponential(x: TensorType, scale: TensorType) -> tf.Tensor:
      return -x / scale - tf.math.log(scale)
  
file_path: GPflow/gpflow/logdensities.py
imports: import numpy
  import tensorflow
  from check_shapes import check_shapes
  from .base import TensorType
  from .utilities import to_default_float
label_desc: Use image node_id 5 for calling a global function with example usage: exponential(x, scale) and returns: unknown