class_docstr: Implements the ohem cross entropy loss function.
  
  Args:
      thresh (float, optional): The threshold of ohem. Default: 0.7.
      min_kept (int, optional): The min number to keep in loss computation. Default: 10000.
      ignore_index (int64, optional): Specifies a target value that is ignored
          and does not contribute to the input gradient. Default ``255``.
code: def __init__(self, thresh=0.7, min_kept=10000, ignore_index=255):
      super(OhemCrossEntropyLoss, self).__init__()
      self.thresh = thresh
      self.min_kept = min_kept
      self.ignore_index = ignore_index
      self.EPS = 1e-5
  
file_path: PaddleSeg/paddleseg/models/losses/ohem_cross_entropy_loss.py
imports: import paddle
  from paddle import nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager
label_desc: Use image node_id 1 to create a new OhemCrossEntropyLoss object from inherited base classes: nn with example: obj = OhemCrossEntropyLoss(thresh, min_kept, ignore_index)