IOSS: Add option to omit_blocks to io_shell

packages/seacas/libraries/ioss/src/Ioss_CopyDatabase.C

@@ -847,6 +847,19 @@ namespace {
         fmt::print(Ioss::DebugOut(), " Number of Nodes                = {:14}\n",
                    fmt::group_digits(num_nodes));
       }
+
+      if (options.omitted_blocks) {
+        size_t isize = inb->get_field("node_connectivity_status").get_size();
+        pool.data.resize(isize);
+        inb->get_field_data("node_connectivity_status", pool.data.data(), isize);
+
+        // Count number of "active" nodes
+        size_t active =
+            std::count_if(pool.data.begin(), pool.data.end(), [](auto &val) { return val >= 2; });
+        fmt::print(Ioss::DebugOut(), " Number of Active Nodes         = {:14}\n",
+                   fmt::group_digits(active));
+      }
+
       auto *nb = new Ioss::NodeBlock(*inb);
       output_region.add(nb);
 

packages/seacas/libraries/ioss/src/Ioss_MeshCopyOptions.h

@@ -36,6 +36,7 @@ namespace Ioss {
     bool reverse{false};          // Used for testing CGNS
     bool add_proc_id{false};      // CGNS: Add proc_id field.
     bool boundary_sideset{false}; // Output a sideset of the boundary faces of the model
+    bool omitted_blocks{false};
 
     // only used by Catalyst calls to `copy_database`; if false the
     // copy process skips the defining of the mesh geometry and the

packages/seacas/libraries/ioss/src/main/io_shell.C

@@ -73,6 +73,7 @@ namespace {
     options.add_proc_id       = interFace.add_processor_id_field;
     options.boundary_sideset  = interFace.boundary_sideset;
     options.ignore_qa_info    = interFace.ignore_qa_info;
+    options.omitted_blocks    = !interFace.omitted_blocks.empty();
     return options;
   }
 
@@ -263,6 +264,11 @@ namespace {
         }
       }
 
+      if (!interFace.omitted_blocks.empty()) {
+        std::vector<std::string> inclusions{};
+        dbi->set_block_omissions(interFace.omitted_blocks, inclusions);
+      }
+
       // NOTE: 'region' owns 'db' pointer at this time...
       Ioss::Region region(dbi, "region_1");
 

packages/seacas/libraries/ioss/src/main/shell_interface.C

@@ -305,6 +305,13 @@ void IOShell::Interface::enroll_options()
                   "\t\tDefault is to ignore empty blocks.",
                   nullptr);
 
+  options_.enroll("omit_blocks", Ioss::GetLongOption::MandatoryValue,
+                  "comma-separated list of element block names that should NOT be transferred to "
+                  "output database\n"
+                  "\t\tNote that currently any nodes connected to only empty blocks will be "
+                  "retained in the output.",
+                  nullptr);
+
   options_.enroll("boundary_sideset", Ioss::GetLongOption::NoValue,
                   "Output a sideset for all boundary faces of the model", nullptr);
 
@@ -606,6 +613,16 @@ bool IOShell::Interface::parse_options(int argc, char **argv, int my_processor)
     }
   }
 
+  {
+    const char *temp = options_.retrieve("omit_blocks");
+    if (temp != nullptr) {
+      auto omit_str = Ioss::tokenize(std::string(temp), ",");
+      for (const auto &str : omit_str) {
+        omitted_blocks.push_back(str);
+      }
+    }
+  }
+
   {
     const char *temp = options_.retrieve("surface_split_scheme");
     if (temp != nullptr) {

packages/seacas/libraries/ioss/src/main/shell_interface.h

@@ -59,6 +59,10 @@ namespace IOShell {
     //! If non-empty, then it is a list of times that should be transferred to the output file.
     std::vector<double> selected_times{};
 
+    //! If non-empty, then it is a list of element blocks that should be omitted from the output
+    //! file
+    std::vector<std::string> omitted_blocks{};
+
     //! If non-zero, then put `split_times` timesteps in each file. Then close file and start new
     //! file.
     // If `split_cyclic == 0`, then filenames will be