class_docstr: Tracks the performance of the algorithm.
code: def prepare_capital_change(self, is_interday):
      self.cumulative_performance.initialize_subperiod_divider()
  
      if not is_interday:
          # Change comes in the middle of day
          self.todays_performance.initialize_subperiod_divider()
  
imports: from __future__ import division
  import logbook
  import pandas
  from pandas.tseries.tools import normalize_date
  from catalyst.finance.performance.period import PerformancePeriod
  from catalyst.errors import NoFurtherDataError
  import catalyst.finance.risk
  from .position_tracker import PositionTracker
  from catalyst.constants import LOG_LEVEL
label_desc: Use image node_id 10 for calling the PerformanceTracker obj's underlying member method code with example usage: obj.prepare_capital_change(is_interday) without return types