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Commit 118a2fa8 authored by Steven Cordwell's avatar Steven Cordwell
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partial rewrite of strings

parent 0296640b
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src/mdptoolbox/mdp.py
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......@@ -118,7 +118,9 @@ class MDP(object):
R : array
Reward vectors.
V : tuple
The optimal value function.
The optimal value function. Each element is a float corresponding to
the expected value of being in that state assuming the optimal policy
is followed.
discount : float
The discount rate on future rewards.
max_iter : int
......@@ -151,8 +153,8 @@ class MDP(object):
self.discount = float(discount)
assert 0.0 < self.discount <= 1.0, "Discount rate must be in ]0; 1]"
if self.discount == 1:
print("PyMDPtoolbox WARNING: check conditions of convergence. "
"With no discount, convergence is not always assumed.")
print("WARNING: check conditions of convergence. With no "
"discount, convergence is can not be assumed.")
# if the max_iter is None then the algorithm is assumed to not use it
# in its computations
if max_iter is not None:
......@@ -292,8 +294,6 @@ class FiniteHorizon(MDP):
"""A MDP solved using the finite-horizon backwards induction algorithm.
Let S = number of states, A = number of actions
Parameters
----------
transitions : array
......@@ -305,23 +305,22 @@ class FiniteHorizon(MDP):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
N = number of periods, upper than 0
h(S) = terminal reward, optional (default [0; 0; ... 0] )
N : int
Number of periods. Must be greater than 0.
h : array, optional
Terminal reward. Default: a vector of zeros.
Attributes
----------
Methods
-------
V(S,N+1) = optimal value function
V(:,n) = optimal value function at stage n
with stage in 1, ..., N
V(:,N+1) = value function for terminal stage
policy(S,N) = optimal policy
policy(:,n) = optimal policy at stage n
with stage in 1, ...,N
policy(:,N) = policy for stage N
cpu_time = used CPU time
Data Attributes
---------------
V : array
Optimal value function. Shape = (S, N+1). ``V[:, n]`` = optimal value
function at stage ``n`` with stage in (0, 1...N-1). ``V[:, N]`` value
function for terminal stage.
policy : array
Optimal policy. ``policy[:, n]`` = optimal policy at stage ``n`` with
stage in (0, 1...N). ``policy[:, N]`` = policy for stage ``N``.
time : float
used CPU time
Notes
-----
......@@ -391,6 +390,8 @@ class FiniteHorizon(MDP):
class LP(MDP):
"""A discounted MDP soloved using linear programming.
This class requires the Python ``cvxopt`` module to be installed.
Arguments
---------
......@@ -403,13 +404,17 @@ class LP(MDP):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
h(S) = terminal reward, optional (default [0; 0; ... 0] )
h : array, optional
Terminal reward. Default: a vector of zeros.
Evaluation
----------
V(S) = optimal values
policy(S) = optimal policy
cpu_time = used CPU time
Data Attributes
---------------
V : tuple
optimal values
policy : tuple
optimal policy
time : float
used CPU time
Notes
-----
......@@ -494,20 +499,26 @@ class PolicyIteration(MDP):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
policy0(S) = starting policy, optional
max_iter : int
policy0 : array, optional
Starting policy.
max_iter : int, optional
Maximum number of iterations. See the documentation for the ``MDP``
class for details. Default is 1000.
eval_type = type of function used to evaluate policy:
0 for mdp_eval_policy_matrix, else mdp_eval_policy_iterative
optional (default 0)
eval_type : int or string, optional
Type of function used to evaluate policy. 0 or "matrix" to solve as a
set of linear equations. 1 or "iterative" to solve iteratively.
Default: 0.
Evaluation
----------
V(S) = value function
policy(S) = optimal policy
iter = number of done iterations
cpu_time = used CPU time
Data Attributes
---------------
V : tuple
value function
policy : tuple
optimal policy
iter : int
number of done iterations
time : float
used CPU time
Notes
-----
......@@ -782,25 +793,23 @@ class PolicyIterationModified(PolicyIteration):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
*policy0(S) = starting policy, optional
max_iter : int
epsilon : float, optional
Stopping criterion. See the documentation for the ``MDP`` class for
details. Default: 0.01.
max_iter : int, optional
Maximum number of iterations. See the documentation for the ``MDP``
class for details. Default is 1000.
eval_type = type of function used to evaluate policy:
0 for mdp_eval_policy_matrix, else mdp_eval_policy_iterative
optional (default 0)
class for details. Default is 10.
Data Attributes
---------------
V(S) = value function
policy(S) = optimal policy
iter = number of done iterations
cpu_time = used CPU time
Notes
-----
In verbose mode, at each iteration, displays the number
of differents actions between policy n-1 and n
V : tuple
value function
policy : tuple
optimal policy
iter : int
number of done iterations
time : float
used CPU time
Examples
--------
......@@ -902,21 +911,21 @@ class QLearning(MDP):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
n_iter : int
Number of iterations to execute. Default value = 10000. This is ignored
unless it is an integer greater than the default value.
Results
-------
Q : learned Q matrix (SxA)
V : learned value function (S).
n_iter : int, optional
Number of iterations to execute. This is ignored unless it is an
integer greater than the default value. Defaut: 10,000.
policy : learned optimal policy (S).
mean_discrepancy : vector of V discrepancy mean over 100 iterations
Then the length of this vector for the default value of N is 100
(N/100).
Data Attributes
---------------
Q : array
learned Q matrix (SxA)
V : tuple
learned value function (S).
policy : tuple
learned optimal policy (S).
mean_discrepancy : array
Vector of V discrepancy mean over 100 iterations. Then the length of
this vector for the default value of N is 100 (N/100).
Examples
---------
......@@ -1057,18 +1066,21 @@ class RelativeValueIteration(MDP):
reward : array
Reward matrices or vectors. See the documentation for the ``MDP`` class
for details.
epsilon : float
epsilon : float, optional
Stopping criterion. See the documentation for the ``MDP`` class for
details.
max_iter : int
details. Default: 0.01.
max_iter : int, optional
Maximum number of iterations. See the documentation for the ``MDP``
class for details. Default = 1000.
class for details. Default: 1000.
Evaluation
----------
policy(S) = epsilon-optimal policy
average_reward = average reward of the optimal policy
cpu_time = used CPU time
Data Attributes
---------------
policy : tuple
epsilon-optimal policy
average_reward : tuple
average reward of the optimal policy
cpu_time : float
used CPU time
Notes
-----
......@@ -1192,25 +1204,22 @@ class ValueIteration(MDP):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
eepsilon : float
epsilon : float, optional
Stopping criterion. See the documentation for the ``MDP`` class for
details.
max_iter : int
Maximum number of iterations. See the documentation for the ``MDP``
class for details. **If the value given in argument is greater than a
computed bound, a warning informs that the computed bound will be
considered. By default, if discount is not equal to 1, a bound for
max_iter is computed, if not max_iter = 1000.**
initial_value : array, optional (default: zeros(S,))
The starting value function. By default ``initial_value`` is composed
of 0 elements.
details. Default: 0.01.
max_iter : int, optional
Maximum number of iterations. If the value given is greater than a
computed bound, a warning informs that the computed bound will be used
instead. By default, if ``discount`` is not equal to 1, a bound for
``max_iter`` is computed, otherwise ``max_iter`` = 1000. See the
documentation for the ``MDP`` class for further details.
initial_value : array, optional
The starting value function. Default: a vector of zeros.
Data Attributes
---------------
V : tuple
The optimal value function. Each element is a float corresponding to
the expected value of being in that state assuming the optimal policy
is followed.
The optimal value function.
policy : tuple
The optimal policy function. Each element is an integer corresponding
to an action which maximises the value function in that state.
......@@ -1221,6 +1230,8 @@ class ValueIteration(MDP):
Methods
-------
run()
Do the algorithm iteration.
setSilent()
Sets the instance to silent mode.
setVerbose()
......@@ -1402,13 +1413,12 @@ class ValueIteration(MDP):
if variation < self.thresh:
if self.verbose:
print("PyMDPToolbox: iteration stopped, epsilon-optimal "
"policy found.")
print("Iteration stopped, epsilon-optimal policy found.")
break
elif (self.iter == self.max_iter):
if self.verbose:
print("PyMDPToolbox: iteration stopped by maximum number "
"of iterations condition.")
print("Iteration stopped by maximum number of iterations "
"condition.")
break
# store value and policy as tuples
......@@ -1422,8 +1432,8 @@ class ValueIterationGS(ValueIteration):
"""
A discounted MDP solved using the value iteration Gauss-Seidel algorithm.
Arguments
---------
Parameters
----------
transitions : array
Transition probability matrices. See the documentation for the ``MDP``
class for details.
......@@ -1433,19 +1443,23 @@ class ValueIterationGS(ValueIteration):
discount : float
Discount factor. See the documentation for the ``MDP`` class for
details.
epsilon : float
epsilon : float, optional
Stopping criterion. See the documentation for the ``MDP`` class for
details.
max_iter : int
details. Default: 0.01.
max_iter : int, optional
Maximum number of iterations. See the documentation for the ``MDP``
and ``ValueIteration`` classes for details. Default: computed.
V0(S) = starting value function, optional (default : zeros(S,1))
initial_value : array, optional
The starting value function. Default: a vector of zeros.
Evaluation
----------
policy(S) = epsilon-optimal policy
iter = number of done iterations
cpu_time = used CPU time
Data Attribues
--------------
policy : tuple
epsilon-optimal policy
iter : int
number of done iterations
time : float
used CPU time
Notes
-----
......@@ -1477,8 +1491,8 @@ class ValueIterationGS(ValueIteration):
self.V = zeros(self.S)
else:
if len(initial_value) != self.S:
raise ValueError("PyMDPtoolbox: The initial value must be "
"a vector of length S.")
raise ValueError("The initial value must be a vector of "
"length S.")
else:
try:
self.V = initial_value.reshape(self.S)
......@@ -1530,14 +1544,13 @@ class ValueIterationGS(ValueIteration):
if variation < self.thresh:
done = True
if self.verbose:
print("MDP Toolbox : iterations stopped, epsilon-optimal "
"policy found.")
print("Iterations stopped, epsilon-optimal policy found.")
elif self.iter == self.max_iter:
done = True
if self.verbose:
print("MDP Toolbox : iterations stopped by maximum number "
"of iteration condition.")
print("Iterations stopped by maximum number of iteration "
"condition.")
self.policy = []
for s in range(self.S):
......
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