class_docstr: Each window is associated with a tuple of coordinates.
  These data properties are used to create TF
  placeholders or ``tf.data.Dataset`` when constructing a TF graph.
  Sampler read the data specifications and fill the placeholder/dataset.
class_docstr_tok: ["Each","window","is","associated","with","a","tuple","of","coordinates",".","These","data","properties","are","used","to","create","TF","placeholders","or","``","tf.data.Dataset","``","when","constructing","a","TF","graph",".","Sampler","read","the","data","specifications","and","fill","the","placeholder\/dataset","."]
docstr: Update the placeholders according to the new n_samples (batch_size).
  Used in the queue-based tensorflow APIs.
  
  :param n_samples:
  :return:
docstr_tok: ["Update","the","placeholders","according","to","the","new","n_samples","(","batch_size",")",".","Used","in","the","queue-based","tensorflow","APIs",".",":","param","n_samples",":",":","return",":"]
code: def _update_placeholders_dict(self, n_samples=1):
      """
      Update the placeholders according to the new n_samples (batch_size).
      Used in the queue-based tensorflow APIs.
  
      :param n_samples:
      :return:
      """
      # batch size=1 if the shapes are dynamic
      self.n_samples = 1 if self.has_dynamic_shapes else n_samples
  
      try:
          self._placeholders_dict = {}
          for name in list(self.tf_dtypes):
              self._placeholders_dict[name] = tf.placeholder(
                  dtype=self.tf_dtypes[name],
                  shape=self.shapes[name],
                  name=name,
              )
      except TypeError:
          tf.logging.fatal(
              "shape should be defined as dict of iterable %s",
              self.shapes,
          )
          raise
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import argparse
  import copy
  import numpy
  import tensorflow
  from tensorflow.python.data.util import nest
  from niftynet.utilities.util_common import ParserNamespace
label_desc: Use image node_id 12 for calling the ImageWindow obj's underlying member method code with example usage: obj._update_placeholders_dict(n_samples) without return types