src/main/java/com/montecarlo/Main.java - master - shvidkuli/kkrjava

src/main/java/com/montecarlo/Main.java
139 строк6 KB
kroc400
first_commit
30 апр 2026, 22:44
30 апр 2026, 22:442347fdb
package com.montecarlo;

import com.montecarlo.geometry.BoundingBox;
import com.montecarlo.geometry.FigureDebf;
import com.montecarlo.montecarlo.MonteCarloCalculator;
import com.montecarlo.montecarlo.MonteCarloCalculator.ExperimentResult;
import com.montecarlo.utils.ConfigReader;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.io.IOException;

/**
 * Application entry point for the Monte Carlo area estimator of figure "debf".
 *
 * <h3>Usage</h3>
 * <pre>
 *   gradle run                          # uses default config path
 *   gradle run --args="path/config.ini" # custom config
 *   java -jar montecarlo-debf.jar path/config.ini
 * </pre>
 *
 * <h3>What it does</h3>
 * <ol>
 *   <li>Reads the INI configuration (rectangle, figure points, experiment sizes).</li>
 *   <li>Constructs the figure "debf" (triangle BEF + semicircle on the D-side of FE).</li>
 *   <li>Logs the bounding box and analytical area.</li>
 *   <li>Runs Monte Carlo experiments for each N in the config.</li>
 *   <li>Prints a profiling table: N | estimated area | relative error | elapsed time.</li>
 * </ol>
 */
public class Main {

    private static final Logger log = LogManager.getLogger(Main.class);

    /** Default path to the configuration file (relative to working directory). */
    private static final String DEFAULT_CONFIG = "src/main/resources/config.ini";

    /**
     * Application entry point.
     *
     * @param args optional: args[0] overrides the configuration file path
     */
    public static void main(String[] args) {
        String configPath = (args.length > 0) ? args[0] : DEFAULT_CONFIG;

        log.info("=== Monte Carlo area estimator — figure 'debf' ===");
        log.info("Configuration file: {}", configPath);

        // ------------------------------------------------------------------
        // Load configuration
        // ------------------------------------------------------------------
        ConfigReader reader = new ConfigReader();
        try {
            reader.load(configPath);
        } catch (IOException e) {
            log.error("Cannot read configuration file '{}': {}", configPath, e.getMessage());
            System.err.println("[ERROR] Cannot read configuration: " + e.getMessage());
            System.exit(1);
        } catch (RuntimeException e) {
            log.error("Invalid configuration: {}", e.getMessage());
            System.err.println("[ERROR] Invalid configuration: " + e.getMessage());
            System.exit(1);
        }

        // ------------------------------------------------------------------
        // Build figure
        // ------------------------------------------------------------------
        FigureDebf figure;
        long[] nValues;
        try {
            figure  = reader.readFigure();
            nValues = reader.readExperimentSizes();
        } catch (RuntimeException e) {
            log.error("Failed to build figure from config: {}", e.getMessage());
            System.err.println("[ERROR] " + e.getMessage());
            System.exit(1);
            return; // unreachable; satisfies compiler
        }

        double analyticalArea = figure.analyticalArea();
        BoundingBox box       = figure.getBoundingBox();

        log.info("Figure      : {}", figure);
        log.info("Bounding box: {}", box);
        log.info("Bounding box area : {}", String.format("%.6f", box.area()));
        log.info("Analytical area   : {}", String.format("%.10f", analyticalArea));
        log.info("Sampling efficiency: {}%",
            String.format("%.2f", analyticalArea / box.area() * 100));

        System.out.println();
        System.out.println("Figure       : " + figure);
        System.out.println("Bounding box : " + box);
        System.out.printf ("Analytical area         = %.10f%n", analyticalArea);
        System.out.printf ("Bounding box area       = %.6f%n", box.area());
        System.out.printf ("Sampling efficiency     = %.2f%%%n%n",
            analyticalArea / box.area() * 100);

        // ------------------------------------------------------------------
        // Run experiments
        // ------------------------------------------------------------------
        MonteCarloCalculator calc = new MonteCarloCalculator(figure);
        ExperimentResult[] results = calc.runAllExperiments(nValues, analyticalArea);

        // ------------------------------------------------------------------
        // Print results table
        // ------------------------------------------------------------------
        String sep = "+" + repeat('-', 14) + "+" + repeat('-', 18) + "+"
                       + repeat('-', 20) + "+" + repeat('-', 14) + "+";
        System.out.println(sep);
        System.out.printf("| %-12s | %-16s | %-18s | %-12s |%n",
            "N", "Area (est.)", "Rel. error (%)", "Time (ms)");
        System.out.println(sep);
        for (ExperimentResult r : results) {
            System.out.printf("| %-12d | %-16.6f | %-18.6f | %-12d |%n",
                r.n, r.estimatedArea, r.relativeErrorPct, r.elapsedMillis);
        }
        System.out.println(sep);
        System.out.printf("| Analytical area: %-54.10f |%n", analyticalArea);
        System.out.println(sep);

        log.info("=== Done ===");
    }

    /**
     * Returns a string consisting of {@code count} repetitions of {@code ch}.
     *
     * @param ch    the character to repeat
     * @param count number of repetitions
     * @return repeated string
     */
    private static String repeat(char ch, int count) {
        StringBuilder sb = new StringBuilder(count);
        for (int i = 0; i < count; i++) {
            sb.append(ch);
        }
        return sb.toString();
    }
}