Fix a bug of using incorrect forest nodes to plant.

Previously some incorrect forest nodes will be used for planting new
nodes.  I cannot fix the root cause of their presence in the
chain-rule machine.  But I can ignore them when they are encountered.

Of course I would like to really prevent them from existing, but still
cannot figure out how.

1 files changed, 17 insertions, 2 deletions

diff --git a/chain/src/default.rs b/chain/src/default.rs
index 1e0eba2..11f0c93 100644
--- a/chain/src/default.rs
+++ b/chain/src/default.rs
@@ -633,6 +633,7 @@ impl Chain for DefaultChain {
                             let mut new_label = *child_label;
 
                             new_label.set_true_source(true_pavi);
+                            // new_label.set_forest_source(pavi);
 
                             output.extend(
                                 std::iter::repeat(new_label.into())
@@ -723,6 +724,20 @@ impl Chain for DefaultChain {
                             continue;
                         }
 
+                        #[allow(clippy::single_match)]
+                        match label.forest_source() {
+                            PaVi::Parent(node, _, _) => match self.forest.vertex_label(node) {
+                                Ok(Some(label)) => match label.label().end() {
+                                    Some(end) if end != pos => {
+                                        continue;
+                                    }
+                                    _ => {}
+                                },
+                                _ => {}
+                            },
+                            _ => {}
+                        }
+
                         let virtual_node = self
                             .atom
                             .atom(non, t)
@@ -911,7 +926,7 @@ impl Chain for DefaultChain {
 
         // First perform reduction.
 
-        let _ = self.forest.print_viz("forest before reduction.gv");
+        // let _ = self.forest.print_viz("forest before reduction.gv");
 
         // self.forest.reduction(root, pos, ter, &self.atom, true)?;
 
@@ -1070,7 +1085,7 @@ impl Chain for DefaultChain {
         self.atom.print_virtual();
         let _ = item::default::print_labels(&self.atom, &self.forest);
 
-        let _ = self.forest.print_viz("forest before extraction.gv");
+        // let _ = self.forest.print_viz("forest before extraction.gv");
 
         result = self.forest.extract(pos)?;