code: def log_phi(x: Tensor) -> Tensor:
      r"""Logarithm of standard normal pdf"""
      log_sqrt_2pi, neg_half = get_constants_like(
          (_log_sqrt_2pi, -0.5), x
      )
      return neg_half * x.square() - log_sqrt_2pi
  
imports: from __future__ import annotations
  import math
  from functools import lru_cache
  from math import pi
  from numbers import Number
  from typing import Any, Callable, Iterable, Iterator, Optional, Tuple, Union
  import torch
  from botorch.utils.safe_math import logdiffexp
  from numpy.polynomial.legendre import leggauss
  from torch import BoolTensor, LongTensor, Tensor
label_desc: Use image node_id 9 for calling a global function with example usage: log_phi(x) and returns: unknown