Merge branch 'master' into dev_visitor

# Conflicts:
#	src/games/gametree.h

Author: tturocy

ChangeLog

@@ -1,27 +1,44 @@
 # Changelog
 
-## [16.5.0] - unreleased
+## [16.5.0] - 2026-01-05
+
+### Fixed
+- Sequence-form based equilibrium-finding methods returned incorrect output on games with
+  outcomes at non-terminal nodes.  (#654)
 
 ### Added
 - Implement `IsAbsentMinded()` on information sets (C++) and `Infoset.is_absent_minded` (Python)
   to detect if an information is absent-minded.
+- Tests for EFG Nash solvers -- `enumpoly_solve`, `lp_solve`, `lcp_solve` -- in behavior strategies
+- In `pygambit`, `Node` objects now have a read-only property `own_prior_action` and `Infoset` objects
+  have a read-only property `own_prior_actions` to retrieve the last action or the set of last actions
+  taken by the player before reaching the node or information set, respectively. (#582)
+- In `pygambit`, `Node` objects now have a read-only property `is_strategy_reachable` to determine
+  if the node is reachable by at least one pure strategy profile. This proves useful for identifying
+  unreachable parts of the game tree in games with absent-mindedness. (#629)
 
 ### Changed
+- Labels for players, outcomes, strategies, and actions are expected to be non-empty and unique within
+  the relevant scope (games for players and outcomes, players for strategies, and information sets for
+  actions).  `pygambit` now issues a `FutureWarning` if a label is changed that does not conform to these
+  expectations.  There is now an optional flag `normalize_labels` to `read_*` which will automatically
+  fill in non-confirming sets of labels.  In version 16.6 these will be enforced; invalid label sets will
+  generate an error and files will be normalized automatically on read. (#614)
+- Terminology for agent-form calculations on extensive games has been clarified.  Mixed behavior profiles
+  distinguish "agent" regret and liap values from their strategy-based analogs.  Methods which compute
+  using the agent-form - specifically `enumpure_solve` and `liap_solve`, now clarify this by being named
+  differently in `pygambit`. (#617)
+- For clarity, the `stop_after` and `max_depth` arguments to `lcp_solve` are no longer permitted when solving using
+  the sequence form.  These actually had no effect in previous versions. (#671)
 - In the graphical interface, removed option to configure information set link drawing; information sets
   are always drawn and indicators are always drawn if an information set spans multiple levels.
 - In `pygambit`, indexing the children of a node by a string inteprets the string as an action label,
   not a label of a child node.  In addition, indexing by an action object is now supported. (#587)
 - In `pygambit`, `min_payoff` and `max_payoff` (for both games and players) now refers to payoffs in
   any play of the game; previously this referred only to the set of outcomes. (#498)
-
-### Added
-- Tests for EFG Nash solvers -- `enumpoly_solve`, `lp_solve`, `lcp_solve` -- in behavior stratgegies
-- In `pygambit`, `Node` objects now have a read-only property `own_prior_action` and `Infoset` objects
-  have a read-only property `own_prior_actions` to retrieve the last action or the set of last actions
-  taken by the player before reaching the node or information set, respectively. (#582)
-- In `pygambit`, `Node` objects now have a read-only property `is_strategy_reachable` to determine
-  if the node is reachable by at least one pure strategy profile. This proves useful for identifying
-  unreachable parts of the game tree in games with absent-mindedness. (#629)
+- In `pygambit`, calls to `sort_infosets` are no longer required to normalise the game representation.
+  Iteration ordering of information sets and their members is ensured internally.  `sort_infosets`
+  is therefore now a no-op and is deprecated; it will be removed in a future version.
 
 ### Removed
 - Eliminating dominated actions has been removed from the GUI as it was implementing a non-standard

Makefile.am

@@ -1,6 +1,6 @@
 ##
 ## This file is part of Gambit
-## Copyright (c) 1994-2025, The Gambit Project (https://www.gambit-project.org)
+## Copyright (c) 1994-2026, The Gambit Project (https://www.gambit-project.org)
 ##
 ## FILE: Makefile.am
 ## Top-level automake input file for Gambit
@@ -249,7 +249,6 @@ core_SOURCES = \
 	src/core/vector.h \
 	src/core/recarray.h \
 	src/core/matrix.h \
-	src/core/matrix.imp \
 	src/core/integer.cc \
 	src/core/integer.h \
 	src/core/rational.cc \

contrib/games/myerson_fig_4_2.efg

@@ -0,0 +1,15 @@
+EFG 2 R "Myerson (1991) Fig 4.2" { "Player 1" "Player 2" }
+"An example from Myerson (1991) Fig 4.2 which has an agent Nash equilibrium that is
+not a Nash equilibrium"
+
+p "" 1 1 "" { "A1" "B1" } 0
+p "" 2 1 "" { "W2" "X2" } 0
+p "" 1 2 "" { "Y1" "Z1" } 0
+t "" 1 "" { 3, 0 }
+t "" 2 "" { 0, 0 }
+p "" 1 2 "" { "Y1" "Z1" } 0
+t "" 3 "" { 2, 3 }
+t "" 4 "" { 4, 1 }
+p "" 2 1 "" { "W2" "X2" } 0
+t "" 5 "" { 2, 3 }
+t "" 6 "" { 3, 2 }

doc/conf.py

@@ -49,7 +49,7 @@
 
 # General information about the project.
 project = "Gambit"
-copyright = "1994-2025, The Gambit Project"  # noqa
+copyright = "1994-2026, The Gambit Project"  # noqa
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the

doc/formats.efg.rst

@@ -6,18 +6,13 @@ The extensive game (.efg) file format
 The extensive game (.efg) file format has been used by Gambit, with
 minor variations, to represent extensive games since circa 1994. It
 replaced an earlier format, which had no particular name but which had
-the conventional extension .dt1. It is intended that some new formats
-will be introduced in the future; however, this format will be
-supported by Gambit, possibly through the use of converter programs to
-those putative future formats, for the foreseeable future.
+the conventional extension .dt1.
 
 
 A sample file
 -------------
 
-This is a sample file illustrating the general format of the file.
-This file is similar to the one distributed in the Gambit distribution
-under the name bayes1a.efg::
+This is a sample file illustrating the general format of the file::
 
     EFG 2 R "General Bayes game, one stage" { "Player 1" "Player 2" }
     c "ROOT" 1 "(0,1)" { "1G" 0.500000 "1B" 0.500000 } 0
@@ -53,8 +48,6 @@ under the name bayes1a.efg::
     t "" 16 "Outcome 16" { 10.000000 0.000000 }
 
 
-
-
 Structure of the prologue
 -------------------------
 
@@ -97,11 +90,9 @@ of one line per node.
 Each node entry begins with an unquoted character indicating the type
 of the node. There are three node types:
 
-
-
-+ c for a chance node
-+ p for a personal player node
-+ t for a terminal node
++ `c` for a chance node
++ `p` for a personal player node
++ `t` for a terminal node
 
 Each node type will be discussed individually below. There are three
 numbering conventions which are used to identify the information
@@ -116,19 +107,21 @@ integer may be used to specify information sets for different players;
 this is not ambiguous since the player number appears as well.
 Finally, outcomes are also arbitrarily numbered in the file format in
 the same way in which information sets are, except for the special
-number 0 which indicates the null outcome.
+number 0 which is reserved to indicate the null outcome.
+Outcome 0 must not have a name or payoffs specified.
 
 Information sets and outcomes may (and frequently will) appear
 multiple times within a game. By convention, the second and subsequent
 times an information set or outcome appears, the file may omit the
 descriptive information for that information set or outcome.
 Alternatively, the file may specify the descriptive information again;
 however, it must precisely match the original declaration of the
-information set or outcome. If any part of the description is omitted,
-the whole description must be omitted.
+information set or outcome. Any mismatch in repeated declarations
+is an error, and the file is not valid.
+If any part of the description is omitted, the whole description must be omitted.
 
 Outcomes may appear at nonterminal nodes. In these cases, payoffs are
-interepreted as incremental payoffs; the payoff to a player for a
+interpreted as incremental payoffs; the payoff to a player for a
 given path through the tree is interpreted as the sum of the payoffs
 at the outcomes encountered on that path (including at the terminal
 node). This is ideal for the representation of games with well-
@@ -146,41 +139,28 @@ with the character c . Following this, in order, are
 
 + a text string, giving the name of the node
 + a positive integer specifying the information set number
-+ (optional) the name of the information set
-+ (optional) a list of actions at the information set with their
++ (optional) the name of the information set and a list of actions at the information set with their
   corresponding probabilities
 + a nonnegative integer specifying the outcome
-+ (optional)the payoffs to each player for the outcome
-
-
++ (optional) the name of the outcome and the payoffs to each player for the outcome
 
 **Format of personal (player) nodes.** Entries for personal player
 decision nodes begin with the character p . Following this, in order,
 are:
 
-
-
 + a text string, giving the name of the node
 + a positive integer specifying the player who owns the node
 + a positive integer specifying the information set
-+ (optional) the name of the information set
-+ (optional) a list of action names for the information set
++ (optional) the name of the information set and a list of action names for the information set
 + a nonnegative integer specifying the outcome
-+ (optional) the name of the outcome
-+ the payoffs to each player for the outcome
-
++ (optional) the name of the outcome and the payoffs to each player for the outcome
 
 
 **Format of terminal nodes.** Entries for terminal nodes begin with
 the character t . Following this, in order, are:
 
-
-
 + a text string, giving the name of the node
 + a nonnegative integer specifying the outcome
-+ (optional) the name of the outcome
-+ the payoffs to each player for the outcome
-
-
++ (optional) the name of the outcome and the payoffs to each player for the outcome
 
 There is no explicit end-of-file delimiter for the file.

doc/pygambit.api.rst

@@ -258,6 +258,8 @@ Probability distributions over behavior
    MixedBehaviorProfile.infoset_prob
    MixedBehaviorProfile.belief
    MixedBehaviorProfile.is_defined_at
+   MixedBehaviorProfile.agent_max_regret
+   MixedBehaviorProfile.agent_liap_value
    MixedBehaviorProfile.max_regret
    MixedBehaviorProfile.liap_value
    MixedBehaviorProfile.as_strategy
@@ -297,11 +299,13 @@ Computation of Nash equilibria
 
    NashComputationResult
    enumpure_solve
+   enumpure_agent_solve
    enummixed_solve
    enumpoly_solve
    lp_solve
    lcp_solve
    liap_solve
+   liap_agent_solve
    logit_solve
    simpdiv_solve
    ipa_solve

doc/tools.convert.rst

@@ -40,7 +40,7 @@ Example invocation for HTML output
 
    $ gambit-convert -O html 2x2.nfg
    Convert games among various file formats
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    <center><h1>Two person 2 x 2 game with unique mixed equilibrium</h1></center>
@@ -55,7 +55,7 @@ Example invocation for LaTeX output
 
    $ gambit-convert -O sgame 2x2.nfg
    Convert games among various file formats
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    \begin{game}{2}{2}[Player 1][Player 2]

doc/tools.enummixed.rst

@@ -70,7 +70,7 @@ in Figure 2 of Selten (International Journal of Game Theory,
 
    $ gambit-enummixed e02.nfg
    Compute Nash equilibria by enumerating extreme points
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    NE,1,0,0,1,0
@@ -82,7 +82,7 @@ information using the `-c` switch
 
    $ gambit-enummixed -c e02.nfg
    Compute Nash equilibria by enumerating extreme points
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    NE,1,0,0,1,0

doc/tools.enumpoly.rst

@@ -98,7 +98,7 @@ Computing equilibria of the strategic game :download:`e01.nfg
 
    $ gambit-enumpoly e01.nfg
    Compute Nash equilibria by solving polynomial systems
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    NE,1.000000,0.000000,1.000000,0.000000,0.000000,1.000000

doc/tools.enumpure.rst

@@ -38,10 +38,10 @@ pure-strategy Nash equilibria.
 
    .. versionadded:: 14.0.2
 
-   Report agent form equilibria, that is, equilibria which consider
-   only deviations at one information set.  Only has an effect for
-   extensive games, as strategic games have only one information set
-   per player.
+   Report agent Nash equilibria, that is, equilibria which consider
+   only deviations at a single information set at a time.  Only has
+   an effect for extensive games, as strategic games have only
+   one information set per player.
 
 .. cmdoption:: -h
 
@@ -60,7 +60,7 @@ Computing the pure-strategy equilibria of extensive game :download:`e02.efg
 
    Search for Nash equilibria in pure strategies
 
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
 
    This is free software, distributed under the GNU GPL
 
@@ -73,7 +73,7 @@ strategies
    $ gambit-enumpure -S e02.efg
 
    Search for Nash equilibria in pure strategies
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    NE,1,0,0,1,0
@@ -84,7 +84,7 @@ only one information set; therefore the set of solutions is larger
 
    $ gambit-enumpure -A e02.efg
    Search for Nash equilibria in pure strategies
-   Gambit version |release|, Copyright (C) 1994-2025, The Gambit Project
+   Gambit version |release|, Copyright (C) 1994-2026, The Gambit Project
    This is free software, distributed under the GNU GPL
 
    NE,1,0,1,0,1,0