config.py

• cfg_from_file(filename)

def cfg_from_file(filename):
  """Load a config file and merge it into the default options."""
  import yaml
  with open(filename, 'r') as f:
    yaml_cfg = edict(yaml.load(f))#将yml文件转换为字典

  _merge_a_into_b(yaml_cfg, __C)

• _merge_a_into_b(a, b)

def _merge_a_into_b(a, b):;将文件a的内容替换到b
  """Merge config dictionary a into config dictionary b, clobbering the
  options in b whenever they are also specified in a.
  """
  if type(a) is not edict:
    return

  for k, v in a.items():;key,value遍历字典
    # a must specify keys that are in b;a的key必须在b中
    if k not in b:
      raise KeyError('{} is not a valid config key'.format(k))

    # the types must match, too;a的value必须与b对应的value类型一致
    old_type = type(b[k])
    if old_type is not type(v):
      if isinstance(b[k], np.ndarray):;判断是否是同一实例,ndarray:N维数组(简称数组)对象，存储单一数据类型的N维数组
        v = np.array(v, dtype=b[k].dtype);np.array()一个函数，返回ndarray实例
      else:
        raise ValueError(('Type mismatch ({} vs. {}) '
                          'for config key: {}').format(type(b[k]),
                                                       type(v), k))

    # recursively merge dicts;递归合并字典
    if type(v) is edict:
      try:
        _merge_a_into_b(a[k], b[k]);递归处理
      except:
        print(('Error under config key: {}'.format(k)))
        raise
    else:
      b[k] = v

cfg_file

• res101.yml

EXP_DIR: res101
TRAIN:
  HAS_RPN: True
  IMS_PER_BATCH: 1
  BBOX_NORMALIZE_TARGETS_PRECOMPUTED: True
  RPN_POSITIVE_OVERLAP: 0.7
  RPN_BATCHSIZE: 256
  PROPOSAL_METHOD: gt
  BG_THRESH_LO: 0.0
  DISPLAY: 20
  BATCH_SIZE: 256
  DOUBLE_BIAS: False
  SNAPSHOT_PREFIX: res101_faster_rcnn
TEST:
  HAS_RPN: True
POOLING_MODE: crop