code: def triangular_size(n: tf.Tensor) -> tf.Tensor:
      """
      Returns the number of non-zero elements in an `n` by `n` triangular matrix.
      """
      return n * (n + 1) // 2
  
file_path: GPflow/gpflow/utilities/bijectors.py
imports: from typing import Optional
  import tensorflow
  import tensorflow_probability
  from check_shapes import check_shapes
  from ..None import config
  from .misc import to_default_float
label_desc: Use image node_id 3 for calling a global function with example usage: triangular_size(n) and returns: unknown