fix : improve engine workers management

src/components/LinearProgressBar.tsx

@@ -12,44 +12,40 @@ const LinearProgressBar = (
   if (props.value === 0) return null;
 
   return (
-    <Grid container alignItems="center" justifyContent="center" size={12}>
+    <Grid
+      container
+      alignItems="center"
+      justifyContent="center"
+      wrap="nowrap"
+      width="90%"
+      columnGap={2}
+      size={12}
+    >
       <Typography variant="caption" align="center">
         {props.label}
       </Typography>
-      <Grid
+      <Grid sx={{ width: "100%" }}>
-        container
+        <LinearProgress
-        width="90%"
+          variant="determinate"
-        alignItems="center"
+          {...props}
-        justifyContent="center"
+          sx={(theme) => ({
-        wrap="nowrap"
+            borderRadius: "5px",
-        columnGap={2}
+            height: "5px",
-        size={12}
+            [`&.${linearProgressClasses.colorPrimary}`]: {
-      >
+              backgroundColor:
-        <Grid sx={{ width: "100%" }}>
+                theme.palette.grey[theme.palette.mode === "light" ? 200 : 700],
-          <LinearProgress
+            },
-            variant="determinate"
+            [`& .${linearProgressClasses.bar}`]: {
-            {...props}
+              borderRadius: 5,
-            sx={(theme) => ({
+              backgroundColor: "#308fe8",
-              borderRadius: "5px",
+            },
-              height: "5px",
+          })}
-              [`&.${linearProgressClasses.colorPrimary}`]: {
+        />
-                backgroundColor:
+      </Grid>
-                  theme.palette.grey[
+      <Grid>
-                    theme.palette.mode === "light" ? 200 : 700
+        <Typography variant="body2" color="text.secondary">{`${Math.round(
-                  ],
+          props.value
-              },
+        )}%`}</Typography>
-              [`& .${linearProgressClasses.bar}`]: {
-                borderRadius: 5,
-                backgroundColor: "#308fe8",
-              },
-            })}
-          />
-        </Grid>
-        <Grid>
-          <Typography variant="body2" color="text.secondary">{`${Math.round(
-            props.value
-          )}%`}</Typography>
-        </Grid>
       </Grid>
     </Grid>
   );

src/hooks/useEngine.ts

@@ -7,10 +7,7 @@ import { UciEngine } from "@/lib/engine/uciEngine";
 import { EngineName } from "@/types/enums";
 import { useEffect, useState } from "react";
 
-export const useEngine = (
+export const useEngine = (engineName: EngineName | undefined) => {
-  engineName: EngineName | undefined,
-  workersNb?: number
-) => {
   const [engine, setEngine] = useState<UciEngine | null>(null);
 
   useEffect(() => {
@@ -20,35 +17,32 @@ export const useEngine = (
       return;
     }
 
-    pickEngine(engineName, workersNb).then((newEngine) => {
+    pickEngine(engineName).then((newEngine) => {
       setEngine((prev) => {
         prev?.shutdown();
         return newEngine;
       });
     });
-  }, [engineName, workersNb]);
+  }, [engineName]);
 
   return engine;
 };
 
-const pickEngine = (
+const pickEngine = (engine: EngineName): Promise<UciEngine> => {
-  engine: EngineName,
-  workersNb?: number
-): Promise<UciEngine> => {
   switch (engine) {
     case EngineName.Stockfish17:
-      return Stockfish17.create(false, workersNb);
+      return Stockfish17.create(false);
     case EngineName.Stockfish17Lite:
-      return Stockfish17.create(true, workersNb);
+      return Stockfish17.create(true);
     case EngineName.Stockfish16_1:
-      return Stockfish16_1.create(false, workersNb);
+      return Stockfish16_1.create(false);
     case EngineName.Stockfish16_1Lite:
-      return Stockfish16_1.create(true, workersNb);
+      return Stockfish16_1.create(true);
     case EngineName.Stockfish16:
-      return Stockfish16.create(false, workersNb);
+      return Stockfish16.create(false);
     case EngineName.Stockfish16NNUE:
-      return Stockfish16.create(true, workersNb);
+      return Stockfish16.create(true);
     case EngineName.Stockfish11:
-      return Stockfish11.create(workersNb);
+      return Stockfish11.create();
   }
 };

src/lib/engine/stockfish11.ts

@@ -1,12 +1,11 @@
 import { EngineName } from "@/types/enums";
 import { UciEngine } from "./uciEngine";
-import { getEngineWorkers } from "./worker";
 
 export class Stockfish11 {
-  public static async create(workersNb?: number): Promise<UciEngine> {
+  public static async create(): Promise<UciEngine> {
-    const workers = getEngineWorkers("engines/stockfish-11.js", workersNb);
+    const enginePath = "engines/stockfish-11.js";
 
-    return UciEngine.create(EngineName.Stockfish11, workers);
+    return UciEngine.create(EngineName.Stockfish11, enginePath);
   }
 
   public static isSupported() {

src/lib/engine/stockfish16.ts

@@ -1,13 +1,11 @@
 import { EngineName } from "@/types/enums";
 import { UciEngine } from "./uciEngine";
 import { isMultiThreadSupported, isWasmSupported } from "./shared";
-import { getEngineWorkers } from "./worker";
+import { sendCommandsToWorker } from "./worker";
+import { EngineWorker } from "@/types/engine";
 
 export class Stockfish16 {
-  public static async create(
+  public static async create(nnue?: boolean): Promise<UciEngine> {
-    nnue?: boolean,
-    workersNb?: number
-  ): Promise<UciEngine> {
     if (!Stockfish16.isSupported()) {
       throw new Error("Stockfish 16 is not supported");
     }
@@ -19,10 +17,9 @@ export class Stockfish16 {
       ? "engines/stockfish-16/stockfish-nnue-16.js"
       : "engines/stockfish-16/stockfish-nnue-16-single.js";
 
-    const customEngineInit = async (
+    const customEngineInit = async (worker: EngineWorker) => {
-      sendCommands: UciEngine["sendCommands"]
+      await sendCommandsToWorker(
-    ) => {
+        worker,
-      await sendCommands(
         [`setoption name Use NNUE value ${!!nnue}`, "isready"],
         "readyok"
       );
@@ -32,9 +29,7 @@ export class Stockfish16 {
       ? EngineName.Stockfish16NNUE
       : EngineName.Stockfish16;
 
-    const workers = getEngineWorkers(enginePath, workersNb);
+    return UciEngine.create(engineName, enginePath, customEngineInit);
-
-    return UciEngine.create(engineName, workers, customEngineInit);
   }
 
   public static isSupported() {

src/lib/engine/stockfish16_1.ts

@@ -1,13 +1,9 @@
 import { EngineName } from "@/types/enums";
 import { UciEngine } from "./uciEngine";
 import { isMultiThreadSupported, isWasmSupported } from "./shared";
-import { getEngineWorkers } from "./worker";
 
 export class Stockfish16_1 {
-  public static async create(
+  public static async create(lite?: boolean): Promise<UciEngine> {
-    lite?: boolean,
-    workersNb?: number
-  ): Promise<UciEngine> {
     if (!Stockfish16_1.isSupported()) {
       throw new Error("Stockfish 16.1 is not supported");
     }
@@ -23,9 +19,7 @@ export class Stockfish16_1 {
       ? EngineName.Stockfish16_1Lite
       : EngineName.Stockfish16_1;
 
-    const workers = getEngineWorkers(enginePath, workersNb);
+    return UciEngine.create(engineName, enginePath);
-
-    return UciEngine.create(engineName, workers);
   }
 
   public static isSupported() {

src/lib/engine/stockfish17.ts

@@ -1,13 +1,9 @@
 import { EngineName } from "@/types/enums";
 import { UciEngine } from "./uciEngine";
 import { isMultiThreadSupported, isWasmSupported } from "./shared";
-import { getEngineWorkers } from "./worker";
 
 export class Stockfish17 {
-  public static async create(
+  public static async create(lite?: boolean): Promise<UciEngine> {
-    lite?: boolean,
-    workersNb?: number
-  ): Promise<UciEngine> {
     if (!Stockfish17.isSupported()) {
       throw new Error("Stockfish 17 is not supported");
     }
@@ -23,9 +19,7 @@ export class Stockfish17 {
       ? EngineName.Stockfish17Lite
       : EngineName.Stockfish17;
 
-    const workers = getEngineWorkers(enginePath, workersNb);
+    return UciEngine.create(engineName, enginePath);
-
-    return UciEngine.create(engineName, workers);
   }
 
   public static isSupported() {

src/lib/engine/uciEngine.ts

@@ -15,38 +15,41 @@ import { getLichessEval } from "../lichess";
 import { getMovesClassification } from "./helpers/moveClassification";
 import { computeEstimatedElo } from "./helpers/estimateElo";
 import { EngineWorker, WorkerJob } from "@/types/engine";
+import { getEngineWorker, sendCommandsToWorker } from "./worker";
 
 export class UciEngine {
-  private workers: EngineWorker[];
+  public readonly name: EngineName;
+  private workers: EngineWorker[] = [];
   private workerQueue: WorkerJob[] = [];
   private isReady = false;
-  private engineName: EngineName;
+  private enginePath: string;
+  private customEngineInit?:
+    | ((worker: EngineWorker) => Promise<void>)
+    | undefined = undefined;
   private multiPv = 3;
   private elo: number | undefined = undefined;
 
-  private constructor(engineName: EngineName, workers: EngineWorker[]) {
+  private constructor(
-    this.engineName = engineName;
+    engineName: EngineName,
-    this.workers = workers;
+    enginePath: string,
+    customEngineInit: UciEngine["customEngineInit"]
+  ) {
+    this.name = engineName;
+    this.enginePath = enginePath;
+    this.customEngineInit = customEngineInit;
   }
 
   public static async create(
     engineName: EngineName,
-    workers: EngineWorker[],
+    enginePath: string,
-    customEngineInit?: (
+    customEngineInit?: UciEngine["customEngineInit"]
-      sendCommands: UciEngine["sendCommands"]
-    ) => Promise<void>
   ): Promise<UciEngine> {
-    const engine = new UciEngine(engineName, workers);
+    const engine = new UciEngine(engineName, enginePath, customEngineInit);
 
-    await engine.broadcastCommands(["uci"], "uciok");
+    await engine.addNewWorker();
-    await engine.setMultiPv(engine.multiPv, true);
-    await customEngineInit?.(engine.sendCommands.bind(engine));
-    for (const worker of workers) {
-      worker.isReady = true;
-    }
     engine.isReady = true;
 
-    console.log(`${engineName} initialized with ${workers.length} workers`);
+    console.log(`${engineName} initialized`);
     return engine;
   }
 
@@ -61,31 +64,34 @@ export class UciEngine {
     return undefined;
   }
 
-  private releaseWorker(worker: EngineWorker) {
+  private async releaseWorker(worker: EngineWorker) {
-    worker.isReady = true;
     const nextJob = this.workerQueue.shift();
-
+    if (!nextJob) {
-    if (nextJob) {
+      worker.isReady = true;
-      this.sendCommands(
+      return;
-        nextJob.commands,
-        nextJob.finalMessage,
-        nextJob.onNewMessage
-      ).then(nextJob.resolve);
     }
+
+    const res = await sendCommandsToWorker(
+      worker,
+      nextJob.commands,
+      nextJob.finalMessage,
+      nextJob.onNewMessage
+    );
+
+    this.releaseWorker(worker);
+    nextJob.resolve(res);
   }
 
-  private async setMultiPv(multiPv: number, initCase = false) {
+  private async setMultiPv(multiPv: number) {
-    if (!initCase) {
+    if (multiPv === this.multiPv) return;
-      if (multiPv === this.multiPv) return;
 
-      this.throwErrorIfNotReady();
+    this.throwErrorIfNotReady();
-    }
 
     if (multiPv < 2 || multiPv > 6) {
       throw new Error(`Invalid MultiPV value : ${multiPv}`);
     }
 
-    await this.broadcastCommands(
+    await this.sendCommandsToEachWorker(
       [`setoption name MultiPV value ${multiPv}`, "isready"],
       "readyok"
     );
@@ -93,23 +99,21 @@ export class UciEngine {
     this.multiPv = multiPv;
   }
 
-  private async setElo(elo: number, initCase = false) {
+  private async setElo(elo: number) {
-    if (!initCase) {
+    if (elo === this.elo) return;
-      if (elo === this.elo) return;
 
-      this.throwErrorIfNotReady();
+    this.throwErrorIfNotReady();
-    }
 
     if (elo < 1320 || elo > 3190) {
       throw new Error(`Invalid Elo value : ${elo}`);
     }
 
-    await this.broadcastCommands(
+    await this.sendCommandsToEachWorker(
       ["setoption name UCI_LimitStrength value true", "isready"],
       "readyok"
     );
 
-    await this.broadcastCommands(
+    await this.sendCommandsToEachWorker(
       [`setoption name UCI_Elo value ${elo}`, "isready"],
       "readyok"
     );
@@ -117,9 +121,13 @@ export class UciEngine {
     this.elo = elo;
   }
 
+  public getIsReady(): boolean {
+    return this.isReady;
+  }
+
   private throwErrorIfNotReady() {
     if (!this.isReady) {
-      throw new Error(`${this.engineName} is not ready`);
+      throw new Error(`${this.name} is not ready`);
     }
   }
 
@@ -128,21 +136,21 @@ export class UciEngine {
     this.workerQueue = [];
 
     for (const worker of this.workers) {
-      worker.uci("quit");
+      this.terminateWorker(worker);
-      worker.terminate?.();
-      worker.isReady = false;
     }
 
-    console.log(`${this.engineName} shutdown`);
+    console.log(`${this.name} shutdown`);
   }
 
-  public getIsReady(): boolean {
+  private terminateWorker(worker: EngineWorker) {
-    return this.isReady;
+    worker.uci("quit");
+    worker.terminate?.();
+    worker.isReady = false;
   }
 
   public async stopSearch(): Promise<void> {
     this.workerQueue = [];
-    await this.broadcastCommands(["stop", "isready"], "readyok");
+    await this.sendCommandsToEachWorker(["stop", "isready"], "readyok");
 
     for (const worker of this.workers) {
       this.releaseWorker(worker);
@@ -167,46 +175,74 @@ export class UciEngine {
       });
     }
 
-    return this.sendCommandsToWorker(
+    const res = await sendCommandsToWorker(
       worker,
       commands,
       finalMessage,
       onNewMessage
     );
+
+    this.releaseWorker(worker);
+    return res;
   }
 
-  private async sendCommandsToWorker(
+  private async sendCommandsToEachWorker(
-    worker: EngineWorker,
-    commands: string[],
-    finalMessage: string,
-    onNewMessage?: (messages: string[]) => void
-  ): Promise<string[]> {
-    return new Promise((resolve) => {
-      const messages: string[] = [];
-      worker.listen = (data) => {
-        messages.push(data);
-        onNewMessage?.(messages);
-
-        if (data.startsWith(finalMessage)) {
-          this.releaseWorker(worker);
-          resolve(messages);
-        }
-      };
-      for (const command of commands) {
-        worker.uci(command);
-      }
-    });
-  }
-
-  private async broadcastCommands(
     commands: string[],
     finalMessage: string,
     onNewMessage?: (messages: string[]) => void
   ): Promise<void> {
     await Promise.all(
-      this.workers.map((worker) =>
+      this.workers.map(async (worker) => {
-        this.sendCommandsToWorker(worker, commands, finalMessage, onNewMessage)
+        await sendCommandsToWorker(
-      )
+          worker,
+          commands,
+          finalMessage,
+          onNewMessage
+        );
+        this.releaseWorker(worker);
+      })
+    );
+  }
+
+  private async addNewWorker() {
+    const worker = getEngineWorker(this.enginePath);
+
+    await sendCommandsToWorker(worker, ["uci"], "uciok");
+    await sendCommandsToWorker(
+      worker,
+      [`setoption name MultiPV value ${this.multiPv}`, "isready"],
+      "readyok"
+    );
+    await this.customEngineInit?.(worker);
+    await sendCommandsToWorker(worker, ["ucinewgame", "isready"], "readyok");
+
+    this.workers.push(worker);
+    this.releaseWorker(worker);
+  }
+
+  private async setWorkersNb(workersNb: number) {
+    if (workersNb === this.workers.length) return;
+
+    if (workersNb < 1) {
+      throw new Error(
+        `Number of workers must be greater than 0, got ${workersNb} instead`
+      );
+    }
+
+    if (workersNb < this.workers.length) {
+      const workersToRemove = this.workers.slice(workersNb);
+      this.workers = this.workers.slice(0, workersNb);
+
+      for (const worker of workersToRemove) {
+        this.terminateWorker(worker);
+      }
+      return;
+    }
+
+    const workersNbToCreate = workersNb - this.workers.length;
+
+    await Promise.all(
+      new Array(workersNbToCreate).fill(0).map(() => this.addNewWorker())
     );
   }
 
@@ -217,13 +253,15 @@ export class UciEngine {
     multiPv = this.multiPv,
     setEvaluationProgress,
     playersRatings,
+    workersNb = 1,
   }: EvaluateGameParams): Promise<GameEval> {
     this.throwErrorIfNotReady();
     setEvaluationProgress?.(1);
     await this.setMultiPv(multiPv);
     this.isReady = false;
 
-    await this.broadcastCommands(["ucinewgame", "isready"], "readyok");
+    await this.sendCommandsToEachWorker(["ucinewgame", "isready"], "readyok");
+    this.setWorkersNb(workersNb);
 
     const positions: PositionEval[] = new Array(fens.length);
     let completed = 0;
@@ -267,10 +305,11 @@ export class UciEngine {
           return;
         }
 
-        const result = await this.evaluatePosition(fen, depth);
+        const result = await this.evaluatePosition(fen, depth, workersNb);
         updateEval(i, result);
       })
     );
+    await this.setWorkersNb(1);
 
     const positionsWithClassification = getMovesClassification(
       positions,
@@ -290,7 +329,7 @@ export class UciEngine {
       estimatedElo,
       accuracy,
       settings: {
-        engine: this.engineName,
+        engine: this.name,
         date: new Date().toISOString(),
         depth,
         multiPv,
@@ -300,9 +339,10 @@ export class UciEngine {
 
   private async evaluatePosition(
     fen: string,
-    depth = 16
+    depth = 16,
+    workersNb: number
   ): Promise<PositionEval> {
-    if (this.workers.length < 2) {
+    if (workersNb < 2) {
       const lichessEval = await getLichessEval(fen, this.multiPv);
       if (
         lichessEval.lines.length >= this.multiPv &&

src/lib/engine/worker.ts

@@ -1,45 +1,59 @@
 import { EngineWorker } from "@/types/engine";
 
-export const getEngineWorkers = (
+export const getEngineWorker = (enginePath: string): EngineWorker => {
-  enginePath: string,
+  console.log(`Creating worker from ${enginePath}`);
-  workersInputNb?: number
-): EngineWorker[] => {
-  if (workersInputNb !== undefined && workersInputNb < 1) {
-    throw new Error(
-      `Number of workers must be greater than 0, got ${workersInputNb} instead`
-    );
-  }
 
-  const engineWorkers: EngineWorker[] = [];
+  const worker = new window.Worker(enginePath);
 
-  const maxWorkersNb = Math.max(
+  const engineWorker: EngineWorker = {
+    isReady: false,
+    uci: (command: string) => worker.postMessage(command),
+    listen: () => null,
+    terminate: () => worker.terminate(),
+  };
+
+  worker.onmessage = (event) => {
+    engineWorker.listen(event.data);
+  };
+
+  return engineWorker;
+};
+
+export const sendCommandsToWorker = (
+  worker: EngineWorker,
+  commands: string[],
+  finalMessage: string,
+  onNewMessage?: (messages: string[]) => void
+): Promise<string[]> => {
+  return new Promise((resolve) => {
+    const messages: string[] = [];
+
+    worker.listen = (data) => {
+      messages.push(data);
+      onNewMessage?.(messages);
+
+      if (data.startsWith(finalMessage)) {
+        resolve(messages);
+      }
+    };
+
+    for (const command of commands) {
+      worker.uci(command);
+    }
+  });
+};
+
+export const getRecommendedWorkersNb = (): number => {
+  const maxWorkersNbFromThreads = Math.max(
     1,
     navigator.hardwareConcurrency - 4,
     Math.ceil((navigator.hardwareConcurrency * 2) / 3)
   );
-  const deviceMemory =
+
+  const maxWorkersNbFromMemory =
     "deviceMemory" in navigator && typeof navigator.deviceMemory === "number"
       ? navigator.deviceMemory
       : 4;
-  const workersNb = workersInputNb ?? Math.min(maxWorkersNb, deviceMemory, 10);
-  console.log(`Starting ${workersNb} workers from ${enginePath}`);
 
-  for (let i = 0; i < workersNb; i++) {
+  return Math.min(maxWorkersNbFromThreads, maxWorkersNbFromMemory, 10);
-    const worker = new window.Worker(enginePath);
-
-    const engineWorker: EngineWorker = {
-      isReady: false,
-      uci: (command: string) => worker.postMessage(command),
-      listen: () => null,
-      terminate: () => worker.terminate(),
-    };
-
-    worker.onmessage = (event) => {
-      engineWorker.listen(event.data);
-    };
-
-    engineWorkers.push(engineWorker);
-  }
-
-  return engineWorkers;
 };

src/sections/analysis/hooks/useCurrentPosition.ts

@@ -10,15 +10,13 @@ import {
 import { CurrentPosition, PositionEval } from "@/types/eval";
 import { useAtom, useAtomValue } from "jotai";
 import { useEffect } from "react";
-import { useEngine } from "../../../hooks/useEngine";
-import { EngineName } from "@/types/enums";
 import { getEvaluateGameParams } from "@/lib/chess";
 import { getMovesClassification } from "@/lib/engine/helpers/moveClassification";
 import { openings } from "@/data/openings";
+import { UciEngine } from "@/lib/engine/uciEngine";
 
-export const useCurrentPosition = (engineName?: EngineName) => {
+export const useCurrentPosition = (engine: UciEngine | null) => {
   const [currentPosition, setCurrentPosition] = useAtom(currentPositionAtom);
-  const engine = useEngine(engineName, 1);
   const gameEval = useAtomValue(gameEvalAtom);
   const game = useAtomValue(gameAtom);
   const board = useAtomValue(boardAtom);
@@ -77,7 +75,7 @@ export const useCurrentPosition = (engineName?: EngineName) => {
     if (
       !position.eval &&
       engine?.getIsReady() &&
-      engineName &&
+      engine.name &&
       !board.isCheckmate() &&
       !board.isStalemate()
     ) {
@@ -85,12 +83,13 @@ export const useCurrentPosition = (engineName?: EngineName) => {
         fen: string,
         setPartialEval?: (positionEval: PositionEval) => void
       ) => {
-        if (!engine?.getIsReady() || !engineName)
+        if (!engine.getIsReady()) {
           throw new Error("Engine not ready");
+        }
         const savedEval = savedEvals[fen];
         if (
           savedEval &&
-          savedEval.engine === engineName &&
+          savedEval.engine === engine.name &&
           (savedEval.lines?.length ?? 0) >= multiPv &&
           (savedEval.lines[0].depth ?? 0) >= depth
         ) {
@@ -111,7 +110,7 @@ export const useCurrentPosition = (engineName?: EngineName) => {
 
         setSavedEvals((prev) => ({
           ...prev,
-          [fen]: { ...rawPositionEval, engine: engineName },
+          [fen]: { ...rawPositionEval, engine: engine.name },
         }));
 
         return rawPositionEval;
@@ -165,7 +164,9 @@ export const useCurrentPosition = (engineName?: EngineName) => {
     }
 
     return () => {
-      engine?.stopSearch();
+      if (engine?.getIsReady()) {
+        engine?.stopSearch();
+      }
     };
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [gameEval, board, game, engine, depth, multiPv]);

src/sections/analysis/panelBody/analysisTab/index.tsx

@@ -7,13 +7,12 @@ import {
 import { useAtomValue } from "jotai";
 import {
   boardAtom,
+  currentPositionAtom,
   engineMultiPvAtom,
-  engineNameAtom,
   gameAtom,
   gameEvalAtom,
 } from "../../states";
 import LineEvaluation from "./lineEvaluation";
-import { useCurrentPosition } from "../../hooks/useCurrentPosition";
 import { LineEval } from "@/types/eval";
 import PlayersMetric from "./playersMetric";
 import MoveInfo from "./moveInfo";
@@ -21,8 +20,7 @@ import Opening from "./opening";
 
 export default function AnalysisTab(props: GridProps) {
   const linesNumber = useAtomValue(engineMultiPvAtom);
-  const engineName = useAtomValue(engineNameAtom);
+  const position = useAtomValue(currentPositionAtom);
-  const position = useCurrentPosition(engineName);
   const game = useAtomValue(gameAtom);
   const board = useAtomValue(boardAtom);
   const gameEval = useAtomValue(gameEvalAtom);

src/sections/analysis/panelHeader/analyzeButton.tsx

@@ -18,10 +18,13 @@ import { SavedEvals } from "@/types/eval";
 import { useEffect, useCallback } from "react";
 import { usePlayersData } from "@/hooks/usePlayersData";
 import { Typography } from "@mui/material";
+import { useCurrentPosition } from "../hooks/useCurrentPosition";
+import { getRecommendedWorkersNb } from "@/lib/engine/worker";
 
 export default function AnalyzeButton() {
   const engineName = useAtomValue(engineNameAtom);
   const engine = useEngine(engineName);
+  useCurrentPosition(engine);
   const [evaluationProgress, setEvaluationProgress] = useAtom(
     evaluationProgressAtom
   );
@@ -55,6 +58,7 @@ export default function AnalyzeButton() {
         white: white?.rating,
         black: black?.rating,
       },
+      workersNb: getRecommendedWorkersNb(),
     });
 
     setEval(newGameEval);

src/sections/play/board.tsx

@@ -19,7 +19,7 @@ import { usePlayersData } from "@/hooks/usePlayersData";
 export default function BoardContainer() {
   const screenSize = useScreenSize();
   const engineName = useAtomValue(enginePlayNameAtom);
-  const engine = useEngine(engineName, 1);
+  const engine = useEngine(engineName);
   const game = useAtomValue(gameAtom);
   const { white, black } = usePlayersData(gameAtom);
   const playerColor = useAtomValue(playerColorAtom);

src/types/eval.ts

@@ -62,6 +62,7 @@ export interface EvaluateGameParams {
   multiPv?: number;
   setEvaluationProgress?: (value: number) => void;
   playersRatings?: { white?: number; black?: number };
+  workersNb?: number;
 }
 
 export interface SavedEval {