code: def student_t(
      x: TensorType, mean: TensorType, scale: TensorType, df: TensorType
  ) -> tf.Tensor:
      df = to_default_float(df)
      const = (
          tf.math.lgamma((df + 1.0) * 0.5)
          - tf.math.lgamma(df * 0.5)
          - 0.5
          * (
              tf.math.log(tf.square(scale))
              + tf.math.log(df)
              + np.log(np.pi)
          )
      )
      return const - 0.5 * (df + 1.0) * tf.math.log(
          1.0 + (1.0 / df) * (tf.square((x - mean) / 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 7 for calling a global function with example usage: student_t(x, mean, scale, df) and returns: unknown