[Operator] add cartesian_product operator to combine a list of lists

gama-platform · Jul 15, 2021 · feb95e0 · feb95e0
1 parent 335f921
commit feb95e0
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Showing 2 changed files with 30 additions and 0 deletions.
diff --git a/msi.gama.core/src/msi/gaml/operators/Containers.java b/msi.gama.core/src/msi/gaml/operators/Containers.java
@@ -18,8 +18,11 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Queue;
+import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
@@ -32,6 +35,7 @@
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Iterators;
 import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
 
 import msi.gama.common.interfaces.IGamlIssue;
 import msi.gama.common.interfaces.IKeyword;
@@ -55,6 +59,7 @@
 import msi.gama.runtime.GAMA;
 import msi.gama.runtime.IScope;
 import msi.gama.runtime.exceptions.GamaRuntimeException;
+import msi.gama.util.Collector;
 import msi.gama.util.GamaColor;
 import msi.gama.util.GamaListFactory;
 import msi.gama.util.GamaListFactory.GamaListSupplier;
@@ -1318,6 +1323,29 @@ public static double sum(final IScope scope, final IGraph g) {
 		if (g == null) return 0.0;
 		return g.computeTotalWeight();
 	}
+
+	@operator (
+			value = "cartesian_product",
+			//can_be_const = true,
+			doc = @doc ("Returns the cartesian product of elements in all given sub-lists"),
+			expected_content_type = { IType.LIST },
+			category = { IOperatorCategory.CONTAINER },
+			concept = { IConcept.CONTAINER }
+			)
+	@test ("cartesian_product([['A','B'],['C','D']]) = [['A','C'],['A','D'],['B','C'],['B','D']]")
+	public static Object cart_prod(final IScope scope, final IList list) {
+		IType ct = list.getGamlType().getContentType();
+		if (!ct.isContainer()) { GamaRuntimeException.error("Must be a list of list", scope); }
+
+		final IList<IList> l = notNull(scope, list).listValue(scope, list.getGamlType().getContentType(), false);
+		List<? extends Set<Object>> setOfSet = l.stream(scope).map(ilist -> new LinkedHashSet<>(ilist)).collect(Collectors.toList());
+
+		IList<IList> res = GamaListFactory.create(ct);
+		Set<List<Object>> cp = Sets.cartesianProduct(setOfSet);
+		for (List cartList : cp) { res.add(GamaListFactory.create(scope, ct.getContentType(), cartList)); }
+
+		return res;
+	}
 
 	@operator (
 			value = { "sum_of" },

diff --git a/msi.gama.models/models/GAML Syntax/Data Types And Structures/Lists.gaml b/msi.gama.models/models/GAML Syntax/Data Types And Structures/Lists.gaml
@@ -134,6 +134,7 @@ species accessing_list_elements {
 species combining_lists {
 	list<int> l1 <- [1,2,3,4,5,6,7,8,9,10];
 	list<int> l2 <- [1,3,5,7,9];
+	list<list> useful_list_of_lists <- [['A','B'],['C','D']]; 
 	init {
 		write "";
 		write "== COMBINING LISTS ==";
@@ -149,6 +150,7 @@ species combining_lists {
 		list<string> l3 <- list<string>(l1 + l2);
 		write "list<string> l3 <- l1 + l2; " + sample(l3);
 		write sample(l1 as list<float>);
+		write sample(cartesian_product(useful_list_of_lists));
 	}
 }