From 82d92280af74223dfc2f0c190413df6725b4b62c Mon Sep 17 00:00:00 2001
From: Bernd Hahnebach <bernd@bimstatik.org>
Date: Fri, 18 Jan 2019 07:31:16 +0100
Subject: [PATCH] FEM: result and mesh, add compact result and mesh, workaround
 for issue #2873

---
 src/Mod/Fem/feminout/importCcxFrdResults.py |  5 ++
 src/Mod/Fem/femmesh/meshtools.py            | 51 +++++++++++++++++++++
 src/Mod/Fem/femresult/resulttools.py        | 24 ++++++++++
 3 files changed, 80 insertions(+)

diff --git a/src/Mod/Fem/feminout/importCcxFrdResults.py b/src/Mod/Fem/feminout/importCcxFrdResults.py
index 96f76398be..9b61e85627 100644
--- a/src/Mod/Fem/feminout/importCcxFrdResults.py
+++ b/src/Mod/Fem/feminout/importCcxFrdResults.py
@@ -105,6 +105,11 @@ def importFrd(filename, analysis=None, result_name_prefix=None):
                 results = ObjectsFem.makeResultMechanical(FreeCAD.ActiveDocument, results_name)
                 results.Mesh = result_mesh_object
                 results = importToolsFem.fill_femresult_mechanical(results, result_set, span)
+                if not results.MassFlowRate:
+                    # only compact result if not Flow 1D results
+                    # compact result object, workaround for bug 2873, https://www.freecadweb.org/tracker/view.php?id=2873
+                    from femresult.resulttools import compact_result as rs
+                    results = rs(results)
                 if analysis:
                     analysis_object.addObject(results)
         else:
diff --git a/src/Mod/Fem/femmesh/meshtools.py b/src/Mod/Fem/femmesh/meshtools.py
index 8e6a8f5dfe..cfc2998f2f 100644
--- a/src/Mod/Fem/femmesh/meshtools.py
+++ b/src/Mod/Fem/femmesh/meshtools.py
@@ -1713,4 +1713,55 @@ def use_correct_fluidinout_ele_def(FluidInletoutlet_ele, fileName, fluid_inout_n
     f.close()
     inout_nodes_file.close()
 
+
+def compact_mesh(old_femmesh):
+    '''
+    removes all gaps in node and element ids, start ids with 1
+    returns a tuple (FemMesh, node_assignment_map, element_assignment_map)
+    '''
+    node_map = {}  # {old_node_id: new_node_id, ...}
+    elem_map = {}  # {old_elem_id: new_elem_id, ...}
+    old_nodes = old_femmesh.Nodes
+    import Fem
+    new_mesh = Fem.FemMesh()
+
+    if old_nodes:
+        for i, n in enumerate(old_nodes):
+            nid = i + 1
+            new_mesh.addNode(old_nodes[n].x, old_nodes[n].y, old_nodes[n].z, nid)
+            node_map[n] = nid
+
+    if old_femmesh.Edges:
+        for i, ed in enumerate(old_femmesh.Edges):
+            eid = i + 1
+            old_elem_nodes = old_femmesh.getElementNodes(ed)
+            new_elemnodes = []
+            for old_node_id in old_elem_nodes:
+                new_elemnodes.append(node_map[old_node_id])
+            new_mesh.addEdge(new_elemnodes, eid)
+            elem_map[ed] = eid
+
+    if old_femmesh.Faces:
+        for i, fa in enumerate(old_femmesh.Faces):
+            fid = i + 1
+            old_elem_nodes = old_femmesh.getElementNodes(fa)
+            new_elemnodes = []
+            for old_node_id in old_elem_nodes:
+                new_elemnodes.append(node_map[old_node_id])
+            new_mesh.addFace(new_elemnodes, fid)
+            elem_map[fa] = fid
+
+    if old_femmesh.Volumes:
+        for i, vo in enumerate(old_femmesh.Volumes):
+            vid = i + 1
+            old_elem_nodes = old_femmesh.getElementNodes(vo)
+            new_elemnodes = []
+            for old_node_id in old_elem_nodes:
+                new_elemnodes.append(node_map[old_node_id])
+            new_mesh.addVolume(new_elemnodes, vid)
+        elem_map[vo] = vid
+
+    # may be return another value if the mesh was compacted, just check last map entries
+    return (new_mesh, node_map, elem_map)
+
 ##  @}
diff --git a/src/Mod/Fem/femresult/resulttools.py b/src/Mod/Fem/femresult/resulttools.py
index 3ece17fc3d..7974ebf9b7 100644
--- a/src/Mod/Fem/femresult/resulttools.py
+++ b/src/Mod/Fem/femresult/resulttools.py
@@ -153,4 +153,28 @@ def get_stats(resultobj, result_type):
     return stats
 
 
+def compact_result(res_obj):
+    '''
+    compacts result.Mesh and appropriate result.NodeNumbers
+    '''
+    # as workaround for https://www.freecadweb.org/tracker/view.php?id=2873
+
+    # get compact mesh data
+    from femmesh.meshtools import compact_mesh as cm
+    compact_femmesh_data = cm(res_obj.Mesh.FemMesh)
+    compact_femmesh = compact_femmesh_data[0]
+    node_map = compact_femmesh_data[1]
+    # elem_map = compact_femmesh_data[2]  # FreeCAD result obj does not support elem results ATM
+
+    # set result mesh
+    res_obj.Mesh.FemMesh = compact_femmesh
+
+    # set result node numbers
+    new_node_numbers = []
+    for old_node_id in res_obj.NodeNumbers:
+        new_node_numbers.append(node_map[old_node_id])
+    res_obj.NodeNumbers = new_node_numbers
+
+    return res_obj
+
 ##  @}