IndexSet::is_empty is added to replace IndexSet::empty

include/godzilla/IndexSet.h

@@ -146,7 +146,8 @@ class IndexSet : public PetscObjectWrapper<IS> {
     /// Checks if the IndexSet is empty (i.e., has no indices)
     ///
     /// @return `true` if the index set is empty, `false` otherwise
-    bool empty() const;
+    [[deprecated]] bool empty() const;
+    bool is_empty() const;
 
     /// Shift all indices by given offset
     ///

src/IndexSet.cpp

@@ -147,6 +147,14 @@ IndexSet::empty() const
     return get_size() == 0;
 }
 
+bool
+IndexSet::is_empty() const
+{
+    CALL_STACK_MSG();
+    GODZILLA_ASSERT_TRUE(this->obj != nullptr, "IndexSet is null");
+    return get_size() == 0;
+}
+
 void
 IndexSet::shift(Int offset)
 {

test/src/IndexSet_test.cpp

@@ -288,6 +288,16 @@ TEST(IndexSetTest, oper_bool)
     EXPECT_TRUE(cis1);
 }
 
+TEST(IndexSetTest, is_empty)
+{
+    TestApp app;
+    if (app.get_comm().size() != 1)
+        return;
+
+    auto is = IndexSet::create_general(app.get_comm(), {});
+    EXPECT_TRUE(is.is_empty());
+}
+
 TEST(IndexSetTest, range)
 {
     TestApp app;