Remove Player entirely from pygambit

ChangeLog

@@ -35,6 +35,9 @@
   of a game in strategic (table) representation.
 - Added `Game.get_payoffs`, which returns the payoff to each player at a pure-strategy
   contingency, for a game in any representation.
+- Added `Game.get_strategies(player)`, `Game.get_sequences(player)`, `Game.get_min_payoff(player)`,
+  and `Game.get_max_payoff(player)`, replacing `Player.strategies`/`.sequences`/`.min_payoff`/
+  `.max_payoff` now that `Player` has been removed.
 
 ### Changed
 - `Infoset` is now a lazy, node-anchored view (like `Node.player`/`Node.outcome`), constructed
@@ -53,6 +56,19 @@
 - `Game.behavior_support_profile`'s `actions` filter callable is now called as
   `actions(node, action)` (two positional arguments, where `node` is a representative node of
   the information set and `action` is the action's label) rather than with a single `Action`.
+- `Node.player` now returns the player's label (`str`), or `None` at a terminal node, directly
+  rather than a lazy `NodePlayer` proxy object. `Infoset.player`/`Event.player`/`Sequence.player`
+  now likewise return a label (`str`) rather than a `Player` object.
+- `StrategySupport.player`, `BehaviorSupport.player`, `MixedStrategy.player`, and
+  `MixedBehavior.player` now return a label (`str`) rather than a `Player` object.
+- `Game.players` now iterates player labels (`str`) rather than `Player` objects; indexing by
+  label is no longer supported (a label is already in hand once iterated) -- use `in` to test
+  membership.
+- `Game.append_move`, `Game.insert_move`, `Game.reveal`, `Game.relabel_strategies`, and
+  `Game.set_strategies` now take `player` as a label (`str`) rather than accepting a `Player`
+  object.
+- `Game.strategy_support_profile`'s `strategies` filter callable's `player` argument is now a
+  label (`str`) rather than a `Player` object.
 - Command-line tools are now implemented in `pygambit` rather than C++-based compiled programs.
   The `gambit-convert` utility has been removed.
 - Refreshed GUI icons and standardised dialog layout and formatting
@@ -78,11 +94,16 @@
   (`pip install gtdraw`) to run tutorials locally or build the documentation.
 - `Game.contingencies` now yields contingencies as a mapping from player label to strategy
   label, rather than a list of per-player strategy indices.
-- `Player.strategies` now iterates strategy labels (`str`) rather than `Strategy` objects;
-  indexing by label is no longer supported (a label is already in hand once iterated) -- use
-  `in` to test membership.
 - `Game.strategy_support_profile`'s `strategies` filter callable is now called as
   `strategies(player, label)` (two positional arguments) rather than with a single `Strategy`.
+- Removed `Player`. Players are now identified purely by label (`str`), as returned by iterating
+  `Game.players`. `Player.strategies`/`.sequences`/`.min_payoff`/`.max_payoff` are replaced by
+  `Game.get_strategies`/`Game.get_sequences`/`Game.get_min_payoff`/`Game.get_max_payoff`;
+  `Player.number` had no remaining use once labels are unambiguous (recover via
+  `list(game.players).index(label)` if truly needed); `Player.is_chance` and `Game.players.chance`
+  are removed outright, with no replacement -- test `Node.event`/`Node.infoset` truthiness
+  instead. `GamePlayerRep` in the C++ core is unaffected by this change (a separate, later piece
+  of work).
 - `Game.get_behavior`'s `player` and `strategy` parameters are now labels (`str`) rather than
   accepting a `Player`/`Strategy` object; `StrategyBehavior.player`/`.strategy` now return
   labels rather than `Player`/`Strategy` objects.

doc/pygambit.api.rst

@@ -14,7 +14,6 @@ Representation of games
    :toctree: api/
 
    Game
-   Player
    Outcome
    Node
    Infoset
@@ -107,28 +106,20 @@ Information about the game
    Game.outcomes
    Game.min_payoff
    Game.max_payoff
+   Game.get_min_payoff
+   Game.get_max_payoff
    Game.root
    Game.get_infosets
    Game.get_events
+   Game.get_strategies
+   Game.get_sequences
    Game.nodes
    Game.contingencies
    Game.get_outcome
    Game.get_payoffs
    Game.subgames
    Game.minimal_subgame
 
-.. autosummary::
-   :toctree: api/
-
-   Player.label
-   Player.number
-   Player.game
-   Player.strategies
-   Player.is_chance
-   Player.min_payoff
-   Player.max_payoff
-   Player.sequences
-
 .. autosummary::
    :toctree: api/
 

doc/tutorials/01_quickstart.ipynb

@@ -76,7 +76,7 @@
    "id": "9d8203e8",
    "metadata": {},
    "outputs": [],
-   "source": "tom, jerry = g.players\ng.relabel_players({tom.label: \"Tom\", jerry.label: \"Jerry\"})\n\nfor player in g.players:\n    cooperate, defect = player.strategies\n    g.relabel_strategies(player, {cooperate: \"Cooperate\", defect: \"Defect\"})"
+   "source": "tom, jerry = g.players\ng.relabel_players({tom: \"Tom\", jerry: \"Jerry\"})\n\nfor player in g.players:\n    cooperate, defect = g.get_strategies(player)\n    g.relabel_strategies(player, {cooperate: \"Cooperate\", defect: \"Defect\"})"
   },
   {
    "cell_type": "markdown",
@@ -268,15 +268,7 @@
    "id": "980bf6b1",
    "metadata": {},
    "outputs": [],
-   "source": [
-    "payoffs = msp.payoffs\n",
-    "for player in g.players:\n",
-    "    print(f\"{player.label} plays the equilibrium strategy:\")\n",
-    "    print(f\"Probability of cooperating: {msp[player.label]['Cooperate']}\")\n",
-    "    print(f\"Probability of defecting: {msp[player.label]['Defect']}\")\n",
-    "    print(f\"Payoff: {payoffs[player.label]}\")\n",
-    "    print()"
-   ]
+   "source": "payoffs = msp.payoffs\nfor player in g.players:\n    print(f\"{player} plays the equilibrium strategy:\")\n    print(f\"Probability of cooperating: {msp[player]['Cooperate']}\")\n    print(f\"Probability of defecting: {msp[player]['Defect']}\")\n    print(f\"Payoff: {payoffs[player]}\")\n    print()"
   },
   {
    "cell_type": "markdown",

doc/tutorials/03_stripped_down_poker.ipynb

@@ -82,21 +82,15 @@
    "cell_type": "markdown",
    "id": "d9796238",
    "metadata": {},
-   "source": [
-    "In addition to the two named players, Gambit also instantiates a chance player."
-   ]
+   "source": "In addition to the two named players, Gambit also instantiates a chance player internally to represent moves of chance. It isn't exposed as a value you can access directly -- `Game.players` lists only the personal players; chance moves are identified via `Node.event` instead (see below)."
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "id": "841f9f74",
    "metadata": {},
    "outputs": [],
-   "source": [
-    "print(g.players[\"Alice\"])\n",
-    "print(g.players[\"Bob\"])\n",
-    "print(g.players.chance)"
-   ]
+   "source": "list(g.players)"
   },
   {
    "cell_type": "markdown",
@@ -538,7 +532,7 @@
    "id": "d4ecff88",
    "metadata": {},
    "outputs": [],
-   "source": "list(g.players[\"Alice\"].strategies)"
+   "source": "g.get_strategies(\"Alice\")"
   },
   {
    "cell_type": "markdown",
@@ -597,7 +591,7 @@
    "id": "56e2f847",
    "metadata": {},
    "outputs": [],
-   "source": "gnm_payoffs = gnm_eqm.payoffs\ngnm_strategy_values = gnm_eqm.strategy_values\nfor player in g.players:\n    print(\n        f\"{player.label}'s expected payoffs playing:\"\n    )\n    for strategy in player.strategies:\n        print(\n            f\"Strategy {strategy}: {gnm_strategy_values[player.label][strategy]:.4f}\"\n        )\n    print(\n        f\"{player.label}'s overall expected payoff: {gnm_payoffs[player.label]:.4f}\"\n    )\n    print()"
+   "source": "gnm_payoffs = gnm_eqm.payoffs\ngnm_strategy_values = gnm_eqm.strategy_values\nfor player in g.players:\n    print(\n        f\"{player}'s expected payoffs playing:\"\n    )\n    for strategy in g.get_strategies(player):\n        print(\n            f\"Strategy {strategy}: {gnm_strategy_values[player][strategy]:.4f}\"\n        )\n    print(\n        f\"{player}'s overall expected payoff: {gnm_payoffs[player]:.4f}\"\n    )\n    print()"
   },
   {
    "cell_type": "markdown",
@@ -618,23 +612,7 @@
    "id": "d18a91f0",
    "metadata": {},
    "outputs": [],
-   "source": [
-    "for player in g.players:\n",
-    "    print(\n",
-    "        f\"{player.label}'s expected payoffs:\"\n",
-    "    )\n",
-    "    gnm_action_values = gnm_eqm.as_behavior().action_values\n",
-    "    lcp_action_values = eqm.action_values\n",
-    "    for node in g.get_infosets(player.label):\n",
-    "        for action in node.actions:\n",
-    "            print(\n",
-    "                f\"At information set {node.infoset.number}, \"\n",
-    "                f\"when playing {action} - \"\n",
-    "                f\"gnm: {gnm_action_values[node][action]:.4f}\"\n",
-    "                f\", lcp: {str(lcp_action_values[node][action])}\"\n",
-    "            )\n",
-    "    print()"
-   ]
+   "source": "for player in g.players:\n    print(\n        f\"{player}'s expected payoffs:\"\n    )\n    gnm_action_values = gnm_eqm.as_behavior().action_values\n    lcp_action_values = eqm.action_values\n    for node in g.get_infosets(player):\n        for action in node.actions:\n            print(\n                f\"At information set {node.infoset.number}, \"\n                f\"when playing {action} - \"\n                f\"gnm: {gnm_action_values[node][action]:.4f}\"\n                f\", lcp: {str(lcp_action_values[node][action])}\"\n            )\n    print()"
   },
   {
    "cell_type": "markdown",

doc/tutorials/advanced_tutorials/agent_versus_non_agent_regret.ipynb

@@ -84,12 +84,7 @@
    "id": "6e3e9303-453a-4bac-a449-fa8fda2ba5ec",
    "metadata": {},
    "outputs": [],
-   "source": [
-    "eq = pure_Nash_equilibria[0]\n",
-    "for behavior in eq.as_behavior():\n",
-    "    for infoset, probs in behavior:\n",
-    "        print(infoset.player.label, \"infoset:\", infoset.number, \"behavior probabilities:\", probs)"
-   ]
+   "source": "eq = pure_Nash_equilibria[0]\nfor behavior in eq.as_behavior():\n    for infoset, probs in behavior:\n        print(infoset.player, \"infoset:\", infoset.number, \"behavior probabilities:\", probs)"
   },
   {
    "cell_type": "markdown",

doc/tutorials/interoperability_tutorials/gamut.ipynb

@@ -391,7 +391,7 @@
    "id": "gamut-bos-gen",
    "metadata": {},
    "outputs": [],
-   "source": "g_chicken = gbt.catalog.generate_gamut(\n    \"Chicken\",\n    params={\n        \"int_payoffs\": True,\n        \"int_mult\": 1,\n        \"normalize\": True,\n        \"min_payoff\": 0,\n        \"max_payoff\": 4,\n    },\n    gamut_jar=\"~/Downloads/gamut.jar\",\n)\ng_chicken.title = \"Chicken\"\nfor player in g_chicken.players:\n    labels = {strategy: label\n              for strategy, label in zip(player.strategies, [\"Swerve\", \"Straight\"], strict=True)}\n    g_chicken.relabel_strategies(player, labels)\ng_chicken"
+   "source": "g_chicken = gbt.catalog.generate_gamut(\n    \"Chicken\",\n    params={\n        \"int_payoffs\": True,\n        \"int_mult\": 1,\n        \"normalize\": True,\n        \"min_payoff\": 0,\n        \"max_payoff\": 4,\n    },\n    gamut_jar=\"~/Downloads/gamut.jar\",\n)\ng_chicken.title = \"Chicken\"\nfor player in g_chicken.players:\n    labels = {strategy: label\n              for strategy, label in zip(\n                  g_chicken.get_strategies(player), [\"Swerve\", \"Straight\"], strict=True\n              )}\n    g_chicken.relabel_strategies(player, labels)\ng_chicken"
   },
   {
    "cell_type": "markdown",

doc/tutorials/interoperability_tutorials/openspiel.ipynb

@@ -156,7 +156,7 @@
    "id": "b684325e",
    "metadata": {},
    "outputs": [],
-   "source": "gbt_matrix_rps_game = gbt.catalog.generate_openspiel(\"matrix_rps\")\n\ngbt_matrix_rps_game.title = \"Rock-Paper-Scissors\"\n\nfor player in gbt_matrix_rps_game.players:\n    names = [\"Rock\", \"Paper\", \"Scissors\"]\n    labels = {strategy: name\n              for strategy, name in zip(player.strategies, names, strict=True)}\n    gbt_matrix_rps_game.relabel_strategies(player, labels)\n\ngbt_matrix_rps_game"
+   "source": "gbt_matrix_rps_game = gbt.catalog.generate_openspiel(\"matrix_rps\")\n\ngbt_matrix_rps_game.title = \"Rock-Paper-Scissors\"\n\nfor player in gbt_matrix_rps_game.players:\n    names = [\"Rock\", \"Paper\", \"Scissors\"]\n    labels = {strategy: name\n              for strategy, name in zip(\n                  gbt_matrix_rps_game.get_strategies(player), names, strict=True\n              )}\n    gbt_matrix_rps_game.relabel_strategies(player, labels)\n\ngbt_matrix_rps_game"
   },
   {
    "cell_type": "markdown",
@@ -343,7 +343,7 @@
    "id": "fcd42af0",
    "metadata": {},
    "outputs": [],
-   "source": "p1_payoffs, p2_payoffs = gbt_prisoners_dilemma_game.to_arrays(dtype=float)\np1, p2 = gbt_prisoners_dilemma_game.players\nops_prisoners_dilemma_game = pyspiel.create_matrix_game(\n    gbt_prisoners_dilemma_game.title,\n    \"Classic Prisoner's Dilemma\",  # description\n    list(p1.strategies),\n    list(p2.strategies),\n    p1_payoffs,\n    p2_payoffs\n)"
+   "source": "p1_payoffs, p2_payoffs = gbt_prisoners_dilemma_game.to_arrays(dtype=float)\np1, p2 = gbt_prisoners_dilemma_game.players\nops_prisoners_dilemma_game = pyspiel.create_matrix_game(\n    gbt_prisoners_dilemma_game.title,\n    \"Classic Prisoner's Dilemma\",  # description\n    gbt_prisoners_dilemma_game.get_strategies(p1),\n    gbt_prisoners_dilemma_game.get_strategies(p2),\n    p1_payoffs,\n    p2_payoffs\n)"
   },
   {
    "cell_type": "markdown",