Initialization Methods

The IDAES toolset contains a number of utility functions to assist users with initializing models.

Available Methods

This module contains utility functions for initialization of IDAES models.

idaes.core.util.initialization.fix_state_vars(blk, state_args={})[source]

Method for fixing state variables within StateBlocks. Method takes an optional argument of values to use when fixing variables.

Parameters:
  • blk – An IDAES StateBlock object in which to fix the state variables
  • state_args – a dict containing values to use when fixing state variables. Keys must match with names used in the define_state_vars method, and indices of any variables must agree.
Returns:

A dict keyed by block index, state variable name (as defined by define_state_variables) and variable index indicating the fixed status of each variable before the fix_state_vars method was applied.
idaes.core.util.initialization.propagate_state(stream, direction='forward')[source]

This method propagates values between Ports along Arcs. Values can be propagated in either direction using the direction argument.

Parameters:
  • stream – Arc object along which to propagate values
  • direction – direction in which to propagate values. Default = ‘forward’ Valid value: ‘forward’, ‘backward’.
Returns:

None
idaes.core.util.initialization.revert_state_vars(blk, flags)[source]

Method to revert the fixed state of the state variables within an IDAES StateBlock based on a set of flags of the previous state.

Parameters:
  • blk – an IDAES StateBlock
  • flags – a dict of bools indicating previous state with keys in the form (StateBlock index, state variable name (as defined by define_state_vars), var indices).
Returns:

None
idaes.core.util.initialization.solve_indexed_blocks(solver, blocks, **kwds)[source]

This method allows for solving of Indexed Block components as if they were a single Block. A temporary Block object is created which is populated with the contents of the objects in the blocks argument and then solved.

Parameters:
  • solver – a Pyomo solver object to use when solving the Indexed Block
  • blocks – an object which inherits from Block, or a list of Blocks
  • kwds – a dict of argumnets to be passed to the solver
Returns:

A Pyomo solver results object