code: def _ndtr(x):
      """Implements ndtr core logic."""
      half_sqrt_2 = constant_op.constant(
          0.5 * np.sqrt(2.0), dtype=x.dtype, name="half_sqrt_2"
      )
      w = x * half_sqrt_2
      z = math_ops.abs(w)
      y = array_ops.where_v2(
          math_ops.less(z, half_sqrt_2),
          1.0 + math_ops.erf(w),
          array_ops.where_v2(
              math_ops.greater(w, 0.0),
              2.0 - math_ops.erfc(z),
              math_ops.erfc(z),
          ),
      )
      return 0.5 * y
  
file_path: tensorflow-upstream/tensorflow/python/ops/distributions/special_math.py
imports: import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
label_desc: Use image node_id 2 for calling a global function with example usage: _ndtr(x) and returns: unknown