class_docstr: Trigger invoked when specific value becomes minimum.
  
  For example you can use this trigger to take snapshot on the epoch the
  validation loss is minimum.
  
  Args:
      key (str): Key of value. The trigger fires when the value associated
          with this key becomes minimum.
      trigger: Trigger that decides the comparison interval between current
          best value and new value. This must be a tuple in the form of
          ``<int>, 'epoch'`` or ``<int>, 'iteration'`` which is passed to
          :class:`~chainer.training.triggers.IntervalTrigger`.
class_docstr_tok: ["Trigger","invoked","when","specific","value","becomes","minimum",".","For","example","you","can","use","this","trigger","to","take","snapshot","on","the","epoch","the","validation","loss","is","minimum",".","Args",":","key","(","str",")",":","Key","of","value",".","The","trigger","fires","when","the","value","associated","with","this","key","becomes","minimum",".","trigger",":","Trigger","that","decides","the","comparison","interval","between","current","best","value","and","new","value",".","This","must","be","a","tuple","in","the","form","of","``","<","int",">",",","'epoch","'","``","or","``","<","int",">",",","'iteration","'","``","which","is","passed","to",":","class",":","`","~chainer.training.triggers.IntervalTrigger","`","."]
code: def __init__(self, key, trigger=(1, "epoch")):
      super(MinValueTrigger, self).__init__(
          key,
          lambda min_value, new_value: new_value < min_value,
          trigger,
      )
  
file_path: chainer/chainer/training/triggers/minmax_value_trigger.py
imports: from chainer import reporter
  from chainer.training import util
label_desc: Use image node_id 1 to create a new MinValueTrigger object from inherited base classes: BestValueTrigger with example: obj = MinValueTrigger(key, trigger)