class_docstr: This is a lightweight stateless class that bundles together instantiation utils.
  It is used both on its own and as a mixin to AxClient, with the intent that
  these methods can be overridden by its subclasses for specific use cases.
class_docstr_tok: ["This","is","a","lightweight","stateless","class","that","bundles","together","instantiation","utils",".","It","is","used","both","on","its","own","and","as","a","mixin","to","AxClient",",","with","the","intent","that","these","methods","can","be","overridden","by","its","subclasses","for","specific","use","cases","."]
docstr: Parse string representation of a parameter constraint.
docstr_tok: ["Parse","string","representation","of","a","parameter","constraint","."]
code: def constraint_from_str(
      representation: str, parameters: Dict[str, Parameter]
  ) -> ParameterConstraint:
      """Parse string representation of a parameter constraint."""
      tokens = representation.split()
      parameter_names = parameters.keys()
      try:
          float(tokens[-1])
          last_token_is_numeric = True
      except ValueError:
          last_token_is_numeric = False
      order_const = len(tokens) == 3 and tokens[1] in COMPARISON_OPS
      sum_const = (
          len(tokens) >= 5
          and len(tokens) % 2 == 1
          and tokens[-2] in COMPARISON_OPS
      )
      if not (order_const or sum_const):
          raise ValueError(
              "Parameter constraint should be of form <parameter_name> >= "
              "<other_parameter_name> for order constraints or `<parameter_name> "
              "+ <other_parameter_name> >= x, where any number of terms can be "
              "added and `x` is a float bound. Acceptable comparison operators "
              'are ">=" and "<=".'
          )
  
      # Case "x1 >= x2" => order constraint.
      if len(tokens) == 3 and not last_token_is_numeric:
          left, right = tokens[0], tokens[2]
          assert (
              left in parameter_names
          ), f"Parameter {left} not in {parameter_names}."
          assert (
              right in parameter_names
          ), f"Parameter {right} not in {parameter_names}."
          return (
              OrderConstraint(
                  lower_parameter=parameters[left],
                  upper_parameter=parameters[right],
              )
              if COMPARISON_OPS[tokens[1]] is ComparisonOp.LEQ
              else OrderConstraint(
                  lower_parameter=parameters[right],
                  upper_parameter=parameters[left],
              )
          )
      if not last_token_is_numeric:
          raise ValueError(
              f"Bound for the constraint must be a number; got {tokens[-1]}"
          )
      bound = float(tokens[-1])
      if any(token[0] == "*" or token[-1] == "*" for token in tokens):
          raise ValueError(
              "A linear constraint should be the form a*x + b*y - c*z <= d"
              ", where a,b,c,d are float constants and x,y,z are parameters. "
              "There should be no space in each term around the operator * while "
              "there should be a single space around each operator +, -, <= and >=."
          )
      parameter_weight = {}
      comparison_multiplier = (
          1.0
          if COMPARISON_OPS[tokens[-2]] is ComparisonOp.LEQ
          else -1.0
      )
      operator_sign = 1.0  # Determines whether the operator is + or -
      # tokens are alternating monomials and operators
      for idx, token in enumerate(tokens[:-2]):
          # for monomials
          if idx % 2 == 0:
              split_token = token.split("*")
              parameter = ""  # Initializing the parameter
              multiplier = 1.0  # Initializing the multiplier
              if (
                  len(split_token) == 2
              ):  # There is a non-unit multiplier
                  try:
                      multiplier = float(split_token[0])
                  except ValueError:
                      raise ValueError(
                          f"Multiplier should be float; got {split_token[0]}"
                      )
                  parameter = split_token[1]
              elif (
                  len(split_token) == 1
              ):  # The multiplier is either -1 or 1
                  parameter = split_token[0]
                  if parameter[0] == "-":  # The multiplier is -1
                      parameter = parameter[1:]
                      multiplier = -1.0
                  else:
                      multiplier = 1.0
              assert (
                  parameter in parameter_names
              ), f"Parameter {parameter} not in {parameter_names}."
              parameter_weight[parameter] = operator_sign * multiplier
          # for operators
          else:
              assert (
                  token == "+" or token == "-"
              ), f"Expected a mixed constraint, found operator {token}."
              operator_sign = 1.0 if token == "+" else -1.0
      return ParameterConstraint(
          constraint_dict={
              p: comparison_multiplier * parameter_weight[p]
              for p in parameter_weight
          },
          bound=comparison_multiplier * bound,
      )
  
imports: import enum
  from dataclasses import dataclass
  from logging import Logger
  from typing import Any, Dict, List, Optional, Sequence, Type, Union
  from ax.core.arm import Arm
  from ax.core.experiment import DataType, DEFAULT_OBJECTIVE_NAME, Experiment
  from ax.core.map_metric import MapMetric
  from ax.core.metric import Metric
  from ax.core.objective import MultiObjective, Objective
  from ax.core.observation import ObservationFeatures
  from ax.core.optimization_config import MultiObjectiveOptimizationConfig, ObjectiveThreshold, OptimizationConfig
  from ax.core.outcome_constraint import OutcomeConstraint
  from ax.core.parameter import ChoiceParameter, FixedParameter, Parameter, PARAMETER_PYTHON_TYPE_MAP, ParameterType, RangeParameter, TParameterType
  from ax.core.parameter_constraint import OrderConstraint, ParameterConstraint
  from ax.core.search_space import HierarchicalSearchSpace, SearchSpace
  from ax.core.types import ComparisonOp, TParameterization, TParamValue
  from ax.exceptions.core import UnsupportedError
  from ax.utils.common.constants import Keys
  from ax.utils.common.logger import get_logger
  from ax.utils.common.typeutils import checked_cast, checked_cast_optional, checked_cast_to_tuple, not_none
label_desc: Use image node_id 9 for calling the InstantiationBase obj's underlying member method code with example usage: obj.constraint_from_str(representation, parameters) and returns: ParameterConstraint, unknown