move FactorSieve main() method to test scope

src/main/java/de/tilman_neumann/jml/factor/FactorSieve.java

@@ -13,7 +13,6 @@
  */
 package de.tilman_neumann.jml.factor;
 
-import java.math.BigInteger;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -22,8 +21,6 @@
 
 import de.tilman_neumann.jml.primes.exact.SegmentedSieve;
 import de.tilman_neumann.jml.primes.exact.SieveCallback;
-import de.tilman_neumann.util.Ensure;
-import de.tilman_neumann.util.ConfigUtil;
 import de.tilman_neumann.util.SortedMultiset;
 import de.tilman_neumann.util.SortedMultiset_BottomUp;
 
@@ -104,7 +101,7 @@ public Map<Long, SortedMultiset<Long>> getFactorizations() {
 		return factorizations;
 	}
 
-	private static long computeProduct(SortedMultiset<Long> factors) {
+	public static long computeProduct(SortedMultiset<Long> factors) {
 		if (factors == null) return 0;
 
 		long result = 1;
@@ -114,34 +111,4 @@ private static long computeProduct(SortedMultiset<Long> factors) {
 		}
 		return result;
 	}
-
-	public static void main(String[] args) {
-		ConfigUtil.initProject();
-
-		long start = 99000000, limit = 100000000;
-		FactorSieve sieve = new FactorSieve(start, limit);
-		long t0 = System.currentTimeMillis();
-		sieve.sieve();
-		long t1 = System.currentTimeMillis();
-		LOG.info("Factoring all numbers from " + start + " to " + limit + " using the sieve took " + (t1-t0) + " milliseconds.");
-		if (DEBUG) {
-			for (long n=start; n<=limit; n++) { // n==1 gives null factors
-				SortedMultiset<Long> factors = sieve.getFactorization(n);
-				LOG.info(n + " = " + factors);
-				if (n>1) {
-					long test = computeProduct(factors);
-					Ensure.ensureEquals(n, test);
-				}
-			}
-		}
-
-		// without batch
-		FactorAlgorithm factorizer = FactorAlgorithm.getDefault();
-		long t2 = System.currentTimeMillis();
-		for (long n=start; n<=limit; n++) {
-			factorizer.factor(BigInteger.valueOf(n));
-		}
-		long t3 = System.currentTimeMillis();
-		LOG.info("Factoring all numbers from " + start + " to " + limit + " individually took " + (t3-t2) + " milliseconds.");
-	}
 }

src/test/java/de/tilman_neumann/jml/factor/FactorSieveDemo.java

@@ -0,0 +1,58 @@
+/*
+ * java-math-library is a Java library focused on number theory, but not necessarily limited to it. It is based on the PSIQS 4.0 factoring project.
+ * Copyright (C) 2018-2024 Tilman Neumann - tilman.neumann@web.de
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with this program;
+ * if not, see <http://www.gnu.org/licenses/>.
+ */
+package de.tilman_neumann.jml.factor;
+
+import java.math.BigInteger;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import de.tilman_neumann.util.ConfigUtil;
+import de.tilman_neumann.util.Ensure;
+import de.tilman_neumann.util.SortedMultiset;
+
+public class FactorSieveDemo {
+	private static final Logger LOG = LogManager.getLogger(FactorSieveDemo.class);
+	private static final boolean DEBUG = false;
+
+	public static void main(String[] args) {
+		ConfigUtil.initProject();
+
+		long start = 99000000, limit = 100000000;
+		FactorSieve sieve = new FactorSieve(start, limit);
+		long t0 = System.currentTimeMillis();
+		sieve.sieve();
+		long t1 = System.currentTimeMillis();
+		LOG.info("Factoring all numbers from " + start + " to " + limit + " using the sieve took " + (t1-t0) + " milliseconds.");
+		if (DEBUG) {
+			for (long n=start; n<=limit; n++) { // n==1 gives null factors
+				SortedMultiset<Long> factors = sieve.getFactorization(n);
+				LOG.info(n + " = " + factors);
+				if (n>1) {
+					long test = FactorSieve.computeProduct(factors);
+					Ensure.ensureEquals(n, test);
+				}
+			}
+		}
+
+		// without batch
+		FactorAlgorithm factorizer = FactorAlgorithm.getDefault();
+		long t2 = System.currentTimeMillis();
+		for (long n=start; n<=limit; n++) {
+			factorizer.factor(BigInteger.valueOf(n));
+		}
+		long t3 = System.currentTimeMillis();
+		LOG.info("Factoring all numbers from " + start + " to " + limit + " individually took " + (t3-t2) + " milliseconds.");
+	}
+}