Source code for pyomo.contrib.parmest.parmest

#  ___________________________________________________________________________
#
#  Pyomo: Python Optimization Modeling Objects
#  Copyright (c) 2008-2024
#  National Technology and Engineering Solutions of Sandia, LLC
#  Under the terms of Contract DE-NA0003525 with National Technology and
#  Engineering Solutions of Sandia, LLC, the U.S. Government retains certain
#  rights in this software.
#  This software is distributed under the 3-clause BSD License.
#  ___________________________________________________________________________
#### Using mpi-sppy instead of PySP; May 2020
#### Adding option for "local" EF starting Sept 2020
#### Wrapping mpi-sppy functionality and local option Jan 2021, Feb 2021

# TODO: move use_mpisppy to a Pyomo configuration option
#
# False implies always use the EF that is local to parmest
use_mpisppy = True  # Use it if we can but use local if not.
if use_mpisppy:
    try:
        # MPI-SPPY has an unfortunate side effect of outputting
        # "[ 0.00] Initializing mpi-sppy" when it is imported.  This can
        # cause things like doctests to fail.  We will suppress that
        # information here.
        from pyomo.common.tee import capture_output

        with capture_output():
            import mpisppy.utils.sputils as sputils
    except ImportError:
        use_mpisppy = False  # we can't use it
if use_mpisppy:
    # These things should be outside the try block.
    sputils.disable_tictoc_output()
    import mpisppy.opt.ef as st
    import mpisppy.scenario_tree as scenario_tree
else:
    import pyomo.contrib.parmest.utils.create_ef as local_ef
    import pyomo.contrib.parmest.utils.scenario_tree as scenario_tree

import re
import importlib as im
import logging
import types
import json
from itertools import combinations

from pyomo.common.dependencies import (
    attempt_import,
    numpy as np,
    numpy_available,
    pandas as pd,
    pandas_available,
    scipy,
    scipy_available,
)

import pyomo.environ as pyo

from pyomo.opt import SolverFactory
from pyomo.environ import Block, ComponentUID

import pyomo.contrib.parmest.utils as utils
import pyomo.contrib.parmest.graphics as graphics
from pyomo.dae import ContinuousSet

parmest_available = numpy_available & pandas_available & scipy_available

inverse_reduced_hessian, inverse_reduced_hessian_available = attempt_import(
    'pyomo.contrib.interior_point.inverse_reduced_hessian'
)

logger = logging.getLogger(__name__)


[docs]def ef_nonants(ef): # Wrapper to call someone's ef_nonants # (the function being called is very short, but it might be changed) if use_mpisppy: return sputils.ef_nonants(ef) else: return local_ef.ef_nonants(ef)
def _experiment_instance_creation_callback( scenario_name, node_names=None, cb_data=None ): """ This is going to be called by mpi-sppy or the local EF and it will call into the user's model's callback. Parameters: ----------- scenario_name: `str` Scenario name should end with a number node_names: `None` ( Not used here ) cb_data : dict with ["callback"], ["BootList"], ["theta_names"], ["cb_data"], etc. "cb_data" is passed through to user's callback function that is the "callback" value. "BootList" is None or bootstrap experiment number list. (called cb_data by mpisppy) Returns: -------- instance: `ConcreteModel` instantiated scenario Note: ---- There is flexibility both in how the function is passed and its signature. """ assert cb_data is not None outer_cb_data = cb_data scen_num_str = re.compile(r'(\d+)$').search(scenario_name).group(1) scen_num = int(scen_num_str) basename = scenario_name[: -len(scen_num_str)] # to reconstruct name CallbackFunction = outer_cb_data["callback"] if callable(CallbackFunction): callback = CallbackFunction else: cb_name = CallbackFunction if "CallbackModule" not in outer_cb_data: raise RuntimeError( "Internal Error: need CallbackModule in parmest callback" ) else: modname = outer_cb_data["CallbackModule"] if isinstance(modname, str): cb_module = im.import_module(modname, package=None) elif isinstance(modname, types.ModuleType): cb_module = modname else: print("Internal Error: bad CallbackModule") raise try: callback = getattr(cb_module, cb_name) except: print("Error getting function=" + cb_name + " from module=" + str(modname)) raise if "BootList" in outer_cb_data: bootlist = outer_cb_data["BootList"] # print("debug in callback: using bootlist=",str(bootlist)) # assuming bootlist itself is zero based exp_num = bootlist[scen_num] else: exp_num = scen_num scen_name = basename + str(exp_num) cb_data = outer_cb_data["cb_data"] # cb_data might be None. # at least three signatures are supported. The first is preferred try: instance = callback(experiment_number=exp_num, cb_data=cb_data) except TypeError: raise RuntimeError( "Only one callback signature is supported: " "callback(experiment_number, cb_data) " ) """ try: instance = callback(scenario_tree_model, scen_name, node_names) except TypeError: # deprecated signature? try: instance = callback(scen_name, node_names) except: print("Failed to create instance using callback; TypeError+") raise except: print("Failed to create instance using callback.") raise """ if hasattr(instance, "_mpisppy_node_list"): raise RuntimeError(f"scenario for experiment {exp_num} has _mpisppy_node_list") nonant_list = [ instance.find_component(vstr) for vstr in outer_cb_data["theta_names"] ] if use_mpisppy: instance._mpisppy_node_list = [ scenario_tree.ScenarioNode( name="ROOT", cond_prob=1.0, stage=1, cost_expression=instance.FirstStageCost, nonant_list=nonant_list, scen_model=instance, ) ] else: instance._mpisppy_node_list = [ scenario_tree.ScenarioNode( name="ROOT", cond_prob=1.0, stage=1, cost_expression=instance.FirstStageCost, scen_name_list=None, nonant_list=nonant_list, scen_model=instance, ) ] if "ThetaVals" in outer_cb_data: thetavals = outer_cb_data["ThetaVals"] # dlw august 2018: see mea code for more general theta for vstr in thetavals: theta_cuid = ComponentUID(vstr) theta_object = theta_cuid.find_component_on(instance) if thetavals[vstr] is not None: # print("Fixing",vstr,"at",str(thetavals[vstr])) theta_object.fix(thetavals[vstr]) else: # print("Freeing",vstr) theta_object.unfix() return instance # ============================================= def _treemaker(scenlist): """ Makes a scenario tree (avoids dependence on daps) Parameters ---------- scenlist (list of `int`): experiment (i.e. scenario) numbers Returns ------- a `ConcreteModel` that is the scenario tree """ num_scenarios = len(scenlist) m = scenario_tree.tree_structure_model.CreateAbstractScenarioTreeModel() m = m.create_instance() m.Stages.add('Stage1') m.Stages.add('Stage2') m.Nodes.add('RootNode') for i in scenlist: m.Nodes.add('LeafNode_Experiment' + str(i)) m.Scenarios.add('Experiment' + str(i)) m.NodeStage['RootNode'] = 'Stage1' m.ConditionalProbability['RootNode'] = 1.0 for node in m.Nodes: if node != 'RootNode': m.NodeStage[node] = 'Stage2' m.Children['RootNode'].add(node) m.Children[node].clear() m.ConditionalProbability[node] = 1.0 / num_scenarios m.ScenarioLeafNode[node.replace('LeafNode_', '')] = node return m
[docs]def group_data(data, groupby_column_name, use_mean=None): """ Group data by scenario Parameters ---------- data: DataFrame Data groupby_column_name: strings Name of data column which contains scenario numbers use_mean: list of column names or None, optional Name of data columns which should be reduced to a single value per scenario by taking the mean Returns ---------- grouped_data: list of dictionaries Grouped data """ if use_mean is None: use_mean_list = [] else: use_mean_list = use_mean grouped_data = [] for exp_num, group in data.groupby(data[groupby_column_name]): d = {} for col in group.columns: if col in use_mean_list: d[col] = group[col].mean() else: d[col] = list(group[col]) grouped_data.append(d) return grouped_data
class _SecondStageCostExpr(object): """ Class to pass objective expression into the Pyomo model """ def __init__(self, ssc_function, data): self._ssc_function = ssc_function self._data = data def __call__(self, model): return self._ssc_function(model, self._data)
[docs]class Estimator(object): """ Parameter estimation class Parameters ---------- model_function: function Function that generates an instance of the Pyomo model using 'data' as the input argument data: pd.DataFrame, list of dictionaries, list of dataframes, or list of json file names Data that is used to build an instance of the Pyomo model and build the objective function theta_names: list of strings List of Var names to estimate obj_function: function, optional Function used to formulate parameter estimation objective, generally sum of squared error between measurements and model variables. If no function is specified, the model is used "as is" and should be defined with a "FirstStageCost" and "SecondStageCost" expression that are used to build an objective. tee: bool, optional Indicates that ef solver output should be teed diagnostic_mode: bool, optional If True, print diagnostics from the solver solver_options: dict, optional Provides options to the solver (also the name of an attribute) """ def __init__( self, model_function, data, theta_names, obj_function=None, tee=False, diagnostic_mode=False, solver_options=None, ): self.model_function = model_function assert isinstance( data, (list, pd.DataFrame) ), "Data must be a list or DataFrame" # convert dataframe into a list of dataframes, each row = one scenario if isinstance(data, pd.DataFrame): self.callback_data = [ data.loc[i, :].to_frame().transpose() for i in data.index ] else: self.callback_data = data assert isinstance( self.callback_data[0], (dict, pd.DataFrame, str) ), "The scenarios in data must be a dictionary, DataFrame or filename" if len(theta_names) == 0: self.theta_names = ['parmest_dummy_var'] else: self.theta_names = theta_names self.obj_function = obj_function self.tee = tee self.diagnostic_mode = diagnostic_mode self.solver_options = solver_options self._second_stage_cost_exp = "SecondStageCost" # boolean to indicate if model is initialized using a square solve self.model_initialized = False def _return_theta_names(self): """ Return list of fitted model parameter names """ # if fitted model parameter names differ from theta_names created when Estimator object is created if hasattr(self, 'theta_names_updated'): return self.theta_names_updated else: return ( self.theta_names ) # default theta_names, created when Estimator object is created def _create_parmest_model(self, data): """ Modify the Pyomo model for parameter estimation """ model = self.model_function(data) if (len(self.theta_names) == 1) and ( self.theta_names[0] == 'parmest_dummy_var' ): model.parmest_dummy_var = pyo.Var(initialize=1.0) # Add objective function (optional) if self.obj_function: for obj in model.component_objects(pyo.Objective): if obj.name in ["Total_Cost_Objective"]: raise RuntimeError( "Parmest will not override the existing model Objective named " + obj.name ) obj.deactivate() for expr in model.component_data_objects(pyo.Expression): if expr.name in ["FirstStageCost", "SecondStageCost"]: raise RuntimeError( "Parmest will not override the existing model Expression named " + expr.name ) model.FirstStageCost = pyo.Expression(expr=0) model.SecondStageCost = pyo.Expression( rule=_SecondStageCostExpr(self.obj_function, data) ) def TotalCost_rule(model): return model.FirstStageCost + model.SecondStageCost model.Total_Cost_Objective = pyo.Objective( rule=TotalCost_rule, sense=pyo.minimize ) # Convert theta Params to Vars, and unfix theta Vars model = utils.convert_params_to_vars(model, self.theta_names) # Update theta names list to use CUID string representation for i, theta in enumerate(self.theta_names): var_cuid = ComponentUID(theta) var_validate = var_cuid.find_component_on(model) if var_validate is None: logger.warning( "theta_name[%s] (%s) was not found on the model", (i, theta) ) else: try: # If the component is not a variable, # this will generate an exception (and the warning # in the 'except') var_validate.unfix() self.theta_names[i] = repr(var_cuid) except: logger.warning(theta + ' is not a variable') self.parmest_model = model return model def _instance_creation_callback(self, experiment_number=None, cb_data=None): # cb_data is a list of dictionaries, list of dataframes, OR list of json file names exp_data = cb_data[experiment_number] if isinstance(exp_data, (dict, pd.DataFrame)): pass elif isinstance(exp_data, str): try: with open(exp_data, 'r') as infile: exp_data = json.load(infile) except: raise RuntimeError(f'Could not read {exp_data} as json') else: raise RuntimeError(f'Unexpected data format for cb_data={cb_data}') model = self._create_parmest_model(exp_data) return model def _Q_opt( self, ThetaVals=None, solver="ef_ipopt", return_values=[], bootlist=None, calc_cov=False, cov_n=None, ): """ Set up all thetas as first stage Vars, return resulting theta values as well as the objective function value. """ if solver == "k_aug": raise RuntimeError("k_aug no longer supported.") # (Bootstrap scenarios will use indirection through the bootlist) if bootlist is None: scenario_numbers = list(range(len(self.callback_data))) scen_names = ["Scenario{}".format(i) for i in scenario_numbers] else: scen_names = ["Scenario{}".format(i) for i in range(len(bootlist))] # tree_model.CallbackModule = None outer_cb_data = dict() outer_cb_data["callback"] = self._instance_creation_callback if ThetaVals is not None: outer_cb_data["ThetaVals"] = ThetaVals if bootlist is not None: outer_cb_data["BootList"] = bootlist outer_cb_data["cb_data"] = self.callback_data # None is OK outer_cb_data["theta_names"] = self.theta_names options = {"solver": "ipopt"} scenario_creator_options = {"cb_data": outer_cb_data} if use_mpisppy: ef = sputils.create_EF( scen_names, _experiment_instance_creation_callback, EF_name="_Q_opt", suppress_warnings=True, scenario_creator_kwargs=scenario_creator_options, ) else: ef = local_ef.create_EF( scen_names, _experiment_instance_creation_callback, EF_name="_Q_opt", suppress_warnings=True, scenario_creator_kwargs=scenario_creator_options, ) self.ef_instance = ef # Solve the extensive form with ipopt if solver == "ef_ipopt": if not calc_cov: # Do not calculate the reduced hessian solver = SolverFactory('ipopt') if self.solver_options is not None: for key in self.solver_options: solver.options[key] = self.solver_options[key] solve_result = solver.solve(self.ef_instance, tee=self.tee) # The import error will be raised when we attempt to use # inv_reduced_hessian_barrier below. # # elif not asl_available: # raise ImportError("parmest requires ASL to calculate the " # "covariance matrix with solver 'ipopt'") else: # parmest makes the fitted parameters stage 1 variables ind_vars = [] for ndname, Var, solval in ef_nonants(ef): ind_vars.append(Var) # calculate the reduced hessian (solve_result, inv_red_hes) = ( inverse_reduced_hessian.inv_reduced_hessian_barrier( self.ef_instance, independent_variables=ind_vars, solver_options=self.solver_options, tee=self.tee, ) ) if self.diagnostic_mode: print( ' Solver termination condition = ', str(solve_result.solver.termination_condition), ) # assume all first stage are thetas... thetavals = {} for ndname, Var, solval in ef_nonants(ef): # process the name # the scenarios are blocks, so strip the scenario name vname = Var.name[Var.name.find(".") + 1 :] thetavals[vname] = solval objval = pyo.value(ef.EF_Obj) if calc_cov: # Calculate the covariance matrix # Number of data points considered n = cov_n # Extract number of fitted parameters l = len(thetavals) # Assumption: Objective value is sum of squared errors sse = objval '''Calculate covariance assuming experimental observation errors are independent and follow a Gaussian distribution with constant variance. The formula used in parmest was verified against equations (7-5-15) and (7-5-16) in "Nonlinear Parameter Estimation", Y. Bard, 1974. This formula is also applicable if the objective is scaled by a constant; the constant cancels out. (was scaled by 1/n because it computes an expected value.) ''' cov = 2 * sse / (n - l) * inv_red_hes cov = pd.DataFrame( cov, index=thetavals.keys(), columns=thetavals.keys() ) thetavals = pd.Series(thetavals) if len(return_values) > 0: var_values = [] if len(scen_names) > 1: # multiple scenarios block_objects = self.ef_instance.component_objects( Block, descend_into=False ) else: # single scenario block_objects = [self.ef_instance] for exp_i in block_objects: vals = {} for var in return_values: exp_i_var = exp_i.find_component(str(var)) if ( exp_i_var is None ): # we might have a block such as _mpisppy_data continue # if value to return is ContinuousSet if type(exp_i_var) == ContinuousSet: temp = list(exp_i_var) else: temp = [pyo.value(_) for _ in exp_i_var.values()] if len(temp) == 1: vals[var] = temp[0] else: vals[var] = temp if len(vals) > 0: var_values.append(vals) var_values = pd.DataFrame(var_values) if calc_cov: return objval, thetavals, var_values, cov else: return objval, thetavals, var_values if calc_cov: return objval, thetavals, cov else: return objval, thetavals else: raise RuntimeError("Unknown solver in Q_Opt=" + solver) def _Q_at_theta(self, thetavals, initialize_parmest_model=False): """ Return the objective function value with fixed theta values. Parameters ---------- thetavals: dict A dictionary of theta values. initialize_parmest_model: boolean If True: Solve square problem instance, build extensive form of the model for parameter estimation, and set flag model_initialized to True Returns ------- objectiveval: float The objective function value. thetavals: dict A dictionary of all values for theta that were input. solvertermination: Pyomo TerminationCondition Tries to return the "worst" solver status across the scenarios. pyo.TerminationCondition.optimal is the best and pyo.TerminationCondition.infeasible is the worst. """ optimizer = pyo.SolverFactory('ipopt') if len(thetavals) > 0: dummy_cb = { "callback": self._instance_creation_callback, "ThetaVals": thetavals, "theta_names": self._return_theta_names(), "cb_data": self.callback_data, } else: dummy_cb = { "callback": self._instance_creation_callback, "theta_names": self._return_theta_names(), "cb_data": self.callback_data, } if self.diagnostic_mode: if len(thetavals) > 0: print(' Compute objective at theta = ', str(thetavals)) else: print(' Compute objective at initial theta') # start block of code to deal with models with no constraints # (ipopt will crash or complain on such problems without special care) instance = _experiment_instance_creation_callback("FOO0", None, dummy_cb) try: # deal with special problems so Ipopt will not crash first = next(instance.component_objects(pyo.Constraint, active=True)) active_constraints = True except: active_constraints = False # end block of code to deal with models with no constraints WorstStatus = pyo.TerminationCondition.optimal totobj = 0 scenario_numbers = list(range(len(self.callback_data))) if initialize_parmest_model: # create dictionary to store pyomo model instances (scenarios) scen_dict = dict() for snum in scenario_numbers: sname = "scenario_NODE" + str(snum) instance = _experiment_instance_creation_callback(sname, None, dummy_cb) if initialize_parmest_model: # list to store fitted parameter names that will be unfixed # after initialization theta_init_vals = [] # use appropriate theta_names member theta_ref = self._return_theta_names() for i, theta in enumerate(theta_ref): # Use parser in ComponentUID to locate the component var_cuid = ComponentUID(theta) var_validate = var_cuid.find_component_on(instance) if var_validate is None: logger.warning( "theta_name %s was not found on the model", (theta) ) else: try: if len(thetavals) == 0: var_validate.fix() else: var_validate.fix(thetavals[theta]) theta_init_vals.append(var_validate) except: logger.warning( 'Unable to fix model parameter value for %s (not a Pyomo model Var)', (theta), ) if active_constraints: if self.diagnostic_mode: print(' Experiment = ', snum) print(' First solve with special diagnostics wrapper') (status_obj, solved, iters, time, regu) = ( utils.ipopt_solve_with_stats( instance, optimizer, max_iter=500, max_cpu_time=120 ) ) print( " status_obj, solved, iters, time, regularization_stat = ", str(status_obj), str(solved), str(iters), str(time), str(regu), ) results = optimizer.solve(instance) if self.diagnostic_mode: print( 'standard solve solver termination condition=', str(results.solver.termination_condition), ) if ( results.solver.termination_condition != pyo.TerminationCondition.optimal ): # DLW: Aug2018: not distinguishing "middlish" conditions if WorstStatus != pyo.TerminationCondition.infeasible: WorstStatus = results.solver.termination_condition if initialize_parmest_model: if self.diagnostic_mode: print( "Scenario {:d} infeasible with initialized parameter values".format( snum ) ) else: if initialize_parmest_model: if self.diagnostic_mode: print( "Scenario {:d} initialization successful with initial parameter values".format( snum ) ) if initialize_parmest_model: # unfix parameters after initialization for theta in theta_init_vals: theta.unfix() scen_dict[sname] = instance else: if initialize_parmest_model: # unfix parameters after initialization for theta in theta_init_vals: theta.unfix() scen_dict[sname] = instance objobject = getattr(instance, self._second_stage_cost_exp) objval = pyo.value(objobject) totobj += objval retval = totobj / len(scenario_numbers) # -1?? if initialize_parmest_model and not hasattr(self, 'ef_instance'): # create extensive form of the model using scenario dictionary if len(scen_dict) > 0: for scen in scen_dict.values(): scen._mpisppy_probability = 1 / len(scen_dict) if use_mpisppy: EF_instance = sputils._create_EF_from_scen_dict( scen_dict, EF_name="_Q_at_theta", # suppress_warnings=True ) else: EF_instance = local_ef._create_EF_from_scen_dict( scen_dict, EF_name="_Q_at_theta", nonant_for_fixed_vars=True ) self.ef_instance = EF_instance # set self.model_initialized flag to True to skip extensive form model # creation using theta_est() self.model_initialized = True # return initialized theta values if len(thetavals) == 0: # use appropriate theta_names member theta_ref = self._return_theta_names() for i, theta in enumerate(theta_ref): thetavals[theta] = theta_init_vals[i]() return retval, thetavals, WorstStatus def _get_sample_list(self, samplesize, num_samples, replacement=True): samplelist = list() scenario_numbers = list(range(len(self.callback_data))) if num_samples is None: # This could get very large for i, l in enumerate(combinations(scenario_numbers, samplesize)): samplelist.append((i, np.sort(l))) else: for i in range(num_samples): attempts = 0 unique_samples = 0 # check for duplicates in each sample duplicate = False # check for duplicates between samples while (unique_samples <= len(self._return_theta_names())) and ( not duplicate ): sample = np.random.choice( scenario_numbers, samplesize, replace=replacement ) sample = np.sort(sample).tolist() unique_samples = len(np.unique(sample)) if sample in samplelist: duplicate = True attempts += 1 if attempts > num_samples: # arbitrary timeout limit raise RuntimeError( """Internal error: timeout constructing a sample, the dim of theta may be too close to the samplesize""" ) samplelist.append((i, sample)) return samplelist
[docs] def theta_est( self, solver="ef_ipopt", return_values=[], calc_cov=False, cov_n=None ): """ Parameter estimation using all scenarios in the data Parameters ---------- solver: string, optional Currently only "ef_ipopt" is supported. Default is "ef_ipopt". return_values: list, optional List of Variable names, used to return values from the model for data reconciliation calc_cov: boolean, optional If True, calculate and return the covariance matrix (only for "ef_ipopt" solver) cov_n: int, optional If calc_cov=True, then the user needs to supply the number of datapoints that are used in the objective function Returns ------- objectiveval: float The objective function value thetavals: pd.Series Estimated values for theta variable values: pd.DataFrame Variable values for each variable name in return_values (only for solver='ef_ipopt') cov: pd.DataFrame Covariance matrix of the fitted parameters (only for solver='ef_ipopt') """ assert isinstance(solver, str) assert isinstance(return_values, list) assert isinstance(calc_cov, bool) if calc_cov: assert isinstance( cov_n, int ), "The number of datapoints that are used in the objective function is required to calculate the covariance matrix" assert cov_n > len( self._return_theta_names() ), "The number of datapoints must be greater than the number of parameters to estimate" return self._Q_opt( solver=solver, return_values=return_values, bootlist=None, calc_cov=calc_cov, cov_n=cov_n, )
[docs] def theta_est_bootstrap( self, bootstrap_samples, samplesize=None, replacement=True, seed=None, return_samples=False, ): """ Parameter estimation using bootstrap resampling of the data Parameters ---------- bootstrap_samples: int Number of bootstrap samples to draw from the data samplesize: int or None, optional Size of each bootstrap sample. If samplesize=None, samplesize will be set to the number of samples in the data replacement: bool, optional Sample with or without replacement seed: int or None, optional Random seed return_samples: bool, optional Return a list of sample numbers used in each bootstrap estimation Returns ------- bootstrap_theta: pd.DataFrame Theta values for each sample and (if return_samples = True) the sample numbers used in each estimation """ assert isinstance(bootstrap_samples, int) assert isinstance(samplesize, (type(None), int)) assert isinstance(replacement, bool) assert isinstance(seed, (type(None), int)) assert isinstance(return_samples, bool) if samplesize is None: samplesize = len(self.callback_data) if seed is not None: np.random.seed(seed) global_list = self._get_sample_list(samplesize, bootstrap_samples, replacement) task_mgr = utils.ParallelTaskManager(bootstrap_samples) local_list = task_mgr.global_to_local_data(global_list) bootstrap_theta = list() for idx, sample in local_list: objval, thetavals = self._Q_opt(bootlist=list(sample)) thetavals['samples'] = sample bootstrap_theta.append(thetavals) global_bootstrap_theta = task_mgr.allgather_global_data(bootstrap_theta) bootstrap_theta = pd.DataFrame(global_bootstrap_theta) if not return_samples: del bootstrap_theta['samples'] return bootstrap_theta
[docs] def theta_est_leaveNout( self, lNo, lNo_samples=None, seed=None, return_samples=False ): """ Parameter estimation where N data points are left out of each sample Parameters ---------- lNo: int Number of data points to leave out for parameter estimation lNo_samples: int Number of leave-N-out samples. If lNo_samples=None, the maximum number of combinations will be used seed: int or None, optional Random seed return_samples: bool, optional Return a list of sample numbers that were left out Returns ------- lNo_theta: pd.DataFrame Theta values for each sample and (if return_samples = True) the sample numbers left out of each estimation """ assert isinstance(lNo, int) assert isinstance(lNo_samples, (type(None), int)) assert isinstance(seed, (type(None), int)) assert isinstance(return_samples, bool) samplesize = len(self.callback_data) - lNo if seed is not None: np.random.seed(seed) global_list = self._get_sample_list(samplesize, lNo_samples, replacement=False) task_mgr = utils.ParallelTaskManager(len(global_list)) local_list = task_mgr.global_to_local_data(global_list) lNo_theta = list() for idx, sample in local_list: objval, thetavals = self._Q_opt(bootlist=list(sample)) lNo_s = list(set(range(len(self.callback_data))) - set(sample)) thetavals['lNo'] = np.sort(lNo_s) lNo_theta.append(thetavals) global_bootstrap_theta = task_mgr.allgather_global_data(lNo_theta) lNo_theta = pd.DataFrame(global_bootstrap_theta) if not return_samples: del lNo_theta['lNo'] return lNo_theta
[docs] def leaveNout_bootstrap_test( self, lNo, lNo_samples, bootstrap_samples, distribution, alphas, seed=None ): """ Leave-N-out bootstrap test to compare theta values where N data points are left out to a bootstrap analysis using the remaining data, results indicate if theta is within a confidence region determined by the bootstrap analysis Parameters ---------- lNo: int Number of data points to leave out for parameter estimation lNo_samples: int Leave-N-out sample size. If lNo_samples=None, the maximum number of combinations will be used bootstrap_samples: int: Bootstrap sample size distribution: string Statistical distribution used to define a confidence region, options = 'MVN' for multivariate_normal, 'KDE' for gaussian_kde, and 'Rect' for rectangular. alphas: list List of alpha values used to determine if theta values are inside or outside the region. seed: int or None, optional Random seed Returns ---------- List of tuples with one entry per lNo_sample: * The first item in each tuple is the list of N samples that are left out. * The second item in each tuple is a DataFrame of theta estimated using the N samples. * The third item in each tuple is a DataFrame containing results from the bootstrap analysis using the remaining samples. For each DataFrame a column is added for each value of alpha which indicates if the theta estimate is in (True) or out (False) of the alpha region for a given distribution (based on the bootstrap results) """ assert isinstance(lNo, int) assert isinstance(lNo_samples, (type(None), int)) assert isinstance(bootstrap_samples, int) assert distribution in ['Rect', 'MVN', 'KDE'] assert isinstance(alphas, list) assert isinstance(seed, (type(None), int)) if seed is not None: np.random.seed(seed) data = self.callback_data.copy() global_list = self._get_sample_list(lNo, lNo_samples, replacement=False) results = [] for idx, sample in global_list: # Reset callback_data to only include the sample self.callback_data = [data[i] for i in sample] obj, theta = self.theta_est() # Reset callback_data to include all scenarios except the sample self.callback_data = [data[i] for i in range(len(data)) if i not in sample] bootstrap_theta = self.theta_est_bootstrap(bootstrap_samples) training, test = self.confidence_region_test( bootstrap_theta, distribution=distribution, alphas=alphas, test_theta_values=theta, ) results.append((sample, test, training)) # Reset callback_data (back to full data set) self.callback_data = data return results
[docs] def objective_at_theta(self, theta_values=None, initialize_parmest_model=False): """ Objective value for each theta Parameters ---------- theta_values: pd.DataFrame, columns=theta_names Values of theta used to compute the objective initialize_parmest_model: boolean If True: Solve square problem instance, build extensive form of the model for parameter estimation, and set flag model_initialized to True Returns ------- obj_at_theta: pd.DataFrame Objective value for each theta (infeasible solutions are omitted). """ if len(self.theta_names) == 1 and self.theta_names[0] == 'parmest_dummy_var': pass # skip assertion if model has no fitted parameters else: # create a local instance of the pyomo model to access model variables and parameters model_temp = self._create_parmest_model(self.callback_data[0]) model_theta_list = [] # list to store indexed and non-indexed parameters # iterate over original theta_names for theta_i in self.theta_names: var_cuid = ComponentUID(theta_i) var_validate = var_cuid.find_component_on(model_temp) # check if theta in theta_names are indexed try: # get component UID of Set over which theta is defined set_cuid = ComponentUID(var_validate.index_set()) # access and iterate over the Set to generate theta names as they appear # in the pyomo model set_validate = set_cuid.find_component_on(model_temp) for s in set_validate: self_theta_temp = repr(var_cuid) + "[" + repr(s) + "]" # generate list of theta names model_theta_list.append(self_theta_temp) # if theta is not indexed, copy theta name to list as-is except AttributeError: self_theta_temp = repr(var_cuid) model_theta_list.append(self_theta_temp) except: raise # if self.theta_names is not the same as temp model_theta_list, # create self.theta_names_updated if set(self.theta_names) == set(model_theta_list) and len( self.theta_names ) == set(model_theta_list): pass else: self.theta_names_updated = model_theta_list if theta_values is None: all_thetas = {} # dictionary to store fitted variables # use appropriate theta names member theta_names = self._return_theta_names() else: assert isinstance(theta_values, pd.DataFrame) # for parallel code we need to use lists and dicts in the loop theta_names = theta_values.columns # # check if theta_names are in model for theta in list(theta_names): theta_temp = theta.replace("'", "") # cleaning quotes from theta_names assert theta_temp in [ t.replace("'", "") for t in model_theta_list ], "Theta name {} in 'theta_values' not in 'theta_names' {}".format( theta_temp, model_theta_list ) assert len(list(theta_names)) == len(model_theta_list) all_thetas = theta_values.to_dict('records') if all_thetas: task_mgr = utils.ParallelTaskManager(len(all_thetas)) local_thetas = task_mgr.global_to_local_data(all_thetas) else: if initialize_parmest_model: task_mgr = utils.ParallelTaskManager( 1 ) # initialization performed using just 1 set of theta values # walk over the mesh, return objective function all_obj = list() if len(all_thetas) > 0: for Theta in local_thetas: obj, thetvals, worststatus = self._Q_at_theta( Theta, initialize_parmest_model=initialize_parmest_model ) if worststatus != pyo.TerminationCondition.infeasible: all_obj.append(list(Theta.values()) + [obj]) # DLW, Aug2018: should we also store the worst solver status? else: obj, thetvals, worststatus = self._Q_at_theta( thetavals={}, initialize_parmest_model=initialize_parmest_model ) if worststatus != pyo.TerminationCondition.infeasible: all_obj.append(list(thetvals.values()) + [obj]) global_all_obj = task_mgr.allgather_global_data(all_obj) dfcols = list(theta_names) + ['obj'] obj_at_theta = pd.DataFrame(data=global_all_obj, columns=dfcols) return obj_at_theta
[docs] def likelihood_ratio_test( self, obj_at_theta, obj_value, alphas, return_thresholds=False ): r""" Likelihood ratio test to identify theta values within a confidence region using the :math:`\chi^2` distribution Parameters ---------- obj_at_theta: pd.DataFrame, columns = theta_names + 'obj' Objective values for each theta value (returned by objective_at_theta) obj_value: int or float Objective value from parameter estimation using all data alphas: list List of alpha values to use in the chi2 test return_thresholds: bool, optional Return the threshold value for each alpha Returns ------- LR: pd.DataFrame Objective values for each theta value along with True or False for each alpha thresholds: pd.Series If return_threshold = True, the thresholds are also returned. """ assert isinstance(obj_at_theta, pd.DataFrame) assert isinstance(obj_value, (int, float)) assert isinstance(alphas, list) assert isinstance(return_thresholds, bool) LR = obj_at_theta.copy() S = len(self.callback_data) thresholds = {} for a in alphas: chi2_val = scipy.stats.chi2.ppf(a, 2) thresholds[a] = obj_value * ((chi2_val / (S - 2)) + 1) LR[a] = LR['obj'] < thresholds[a] thresholds = pd.Series(thresholds) if return_thresholds: return LR, thresholds else: return LR
[docs] def confidence_region_test( self, theta_values, distribution, alphas, test_theta_values=None ): """ Confidence region test to determine if theta values are within a rectangular, multivariate normal, or Gaussian kernel density distribution for a range of alpha values Parameters ---------- theta_values: pd.DataFrame, columns = theta_names Theta values used to generate a confidence region (generally returned by theta_est_bootstrap) distribution: string Statistical distribution used to define a confidence region, options = 'MVN' for multivariate_normal, 'KDE' for gaussian_kde, and 'Rect' for rectangular. alphas: list List of alpha values used to determine if theta values are inside or outside the region. test_theta_values: pd.Series or pd.DataFrame, keys/columns = theta_names, optional Additional theta values that are compared to the confidence region to determine if they are inside or outside. Returns training_results: pd.DataFrame Theta value used to generate the confidence region along with True (inside) or False (outside) for each alpha test_results: pd.DataFrame If test_theta_values is not None, returns test theta value along with True (inside) or False (outside) for each alpha """ assert isinstance(theta_values, pd.DataFrame) assert distribution in ['Rect', 'MVN', 'KDE'] assert isinstance(alphas, list) assert isinstance( test_theta_values, (type(None), dict, pd.Series, pd.DataFrame) ) if isinstance(test_theta_values, (dict, pd.Series)): test_theta_values = pd.Series(test_theta_values).to_frame().transpose() training_results = theta_values.copy() if test_theta_values is not None: test_result = test_theta_values.copy() for a in alphas: if distribution == 'Rect': lb, ub = graphics.fit_rect_dist(theta_values, a) training_results[a] = (theta_values > lb).all(axis=1) & ( theta_values < ub ).all(axis=1) if test_theta_values is not None: # use upper and lower bound from the training set test_result[a] = (test_theta_values > lb).all(axis=1) & ( test_theta_values < ub ).all(axis=1) elif distribution == 'MVN': dist = graphics.fit_mvn_dist(theta_values) Z = dist.pdf(theta_values) score = scipy.stats.scoreatpercentile(Z, (1 - a) * 100) training_results[a] = Z >= score if test_theta_values is not None: # use score from the training set Z = dist.pdf(test_theta_values) test_result[a] = Z >= score elif distribution == 'KDE': dist = graphics.fit_kde_dist(theta_values) Z = dist.pdf(theta_values.transpose()) score = scipy.stats.scoreatpercentile(Z, (1 - a) * 100) training_results[a] = Z >= score if test_theta_values is not None: # use score from the training set Z = dist.pdf(test_theta_values.transpose()) test_result[a] = Z >= score if test_theta_values is not None: return training_results, test_result else: return training_results