class_docstr: A sequence of potential optimizations.
  
  Retrieve a sequence of optimizations (a SeqOptimizer) by calling query().
  
  Each potential optimization is registered with a floating-point position.
  No matter which optimizations are selected by a query, they are carried
  out in order of increasing position.
  
  The optdb itself (`theano.compile.mode.optdb`), from which (among many
  other tags) fast_run and fast_compile optimizers are drawn is a SequenceDB.
class_docstr_tok: ["A","sequence","of","potential","optimizations",".","Retrieve","a","sequence","of","optimizations","(","a","SeqOptimizer",")","by","calling","query","(",")",".","Each","potential","optimization","is","registered","with","a","floating-point","position",".","No","matter","which","optimizations","are","selected","by","a","query",",","they","are","carried","out","in","order","of","increasing","position",".","The","optdb","itself","(","`","theano.compile.mode.optdb","`",")",",","from","which","(","among","many","other","tags",")","fast_run","and","fast_compile","optimizers","are","drawn","is","a","SequenceDB","."]
code: def register(self, name, obj, position, *tags):
      super(SequenceDB, self).register(name, obj, *tags)
      if position == "last":
          if len(self.__position__) == 0:
              self.__position__[name] = 0
          else:
              self.__position__[name] = (
                  max(self.__position__.values()) + 1
              )
      else:
          assert isinstance(position, (integer_types, float))
          self.__position__[name] = position
  
imports: from __future__ import absolute_import, print_function, division
  import copy
  import sys
  from theano.compat import DefaultOrderedDict
  from theano.misc.ordered_set import OrderedSet
  from six import StringIO, integer_types
  from theano.gof import opt
  from theano import config
label_desc: Use image node_id 2 for calling the SequenceDB obj's underlying member method code with example usage: obj.register(name, obj, position) without return types