ENH: direct ensight output of float/double

- since ensight format is always float and also always written
  component-wise, perform the double -> float narrowing when
  extracting the components.  This reduces the amount of data
  transferred between processors.

ENH: avoid vtk/ensight parallel communication of empty messages

- since ensight writes by element type (eg, tet, hex, polyhedral) the
  individual written field sections will tend to be relatively sparse.
  Skip zero-size messages, which should help reduce some of the
  synchronization bottlenecks.

ENH: use 'data chunking' when writing ensight files in parallel

- since ensight fields are written on a per-element basis, the
  corresponding segment can become rather sparsely distributed. With
  'data chunking', we attempt to get as many send/recv messages in
  before flushing the buffer for writing. This should make the
  sequential send/recv less affected by the IO time.

ENH: allow use of an external buffer when writing ensight components

STYLE: remove last vestiges of autoPtr<ensightFile> for output routines

src/functionObjects/utilities/ensightWrite/ensightWrite.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -26,6 +26,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "ensightWrite.H"
+#include "ensightOutput.H"
 #include "Time.H"
 #include "polyMesh.H"
 #include "addToRunTimeSelectionTable.H"
@@ -47,6 +48,9 @@ namespace functionObjects
 }
 }
 
+// Implementation
+#include "ensightWriteImpl.C"
+
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 Foam::label Foam::functionObjects::ensightWrite::writeAllVolFields
@@ -57,11 +61,26 @@ Foam::label Foam::functionObjects::ensightWrite::writeAllVolFields
 {
     label count = 0;
 
-    count += writeVolFields<scalar>(proxy, acceptField);
-    count += writeVolFields<vector>(proxy, acceptField);
-    count += writeVolFields<sphericalTensor>(proxy, acceptField);
-    count += writeVolFields<symmTensor>(proxy, acceptField);
-    count += writeVolFields<tensor>(proxy, acceptField);
+    ensightOutput::floatBufferType scratch;
+
+    {
+        #undef  doLocalCode
+        #define doLocalCode(PrimitiveType)              \
+            count += writeVolFieldsImpl<PrimitiveType>  \
+            (                                           \
+                scratch,                                \
+                proxy,                                  \
+                acceptField                             \
+            );
+
+        doLocalCode(scalar);
+        doLocalCode(vector);
+        doLocalCode(sphericalTensor);
+        doLocalCode(symmTensor);
+        doLocalCode(tensor);
+
+        #undef doLocalCode
+    }
 
     return count;
 }
@@ -215,6 +234,8 @@ bool Foam::functionObjects::ensightWrite::write()
         ensMesh_().write(os);
     }
 
+    // TBD: handle allow/deny filters
+
     wordHashSet acceptField(mesh_.names<void>(selectFields_));
 
     // Prune restart fields

src/functionObjects/utilities/ensightWrite/ensightWrite.H

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -127,16 +127,18 @@ See also
 
 SourceFiles
     ensightWrite.C
-    ensightWriteTemplates.C
+    ensightWriteImpl.C
+    ensightWriteUpdate.C
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef functionObjects_ensightWrite_H
-#define functionObjects_ensightWrite_H
+#ifndef Foam_functionObjects_ensightWrite_H
+#define Foam_functionObjects_ensightWrite_H
 
 #include "fvMeshFunctionObject.H"
 #include "ensightCase.H"
 #include "ensightMesh.H"
+#include "ensightOutputFwd.H"
 
 #include "interpolation.H"
 #include "volFields.H"
@@ -223,6 +225,15 @@ class ensightWrite
 
     // Write
 
+        //- Write selected volume fields.
+        template<class Type>
+        label writeVolFieldsImpl
+        (
+            ensightOutput::floatBufferType& scratch,
+            const fvMeshSubset& proxy,
+            const wordHashSet& acceptField
+        );
+
         //- Write all volume fields
         label writeAllVolFields
         (
@@ -230,15 +241,6 @@ class ensightWrite
             const wordHashSet& acceptField
         );
 
-        //- Write selected volume fields.
-        template<class Type>
-        label writeVolFields
-        (
-            const fvMeshSubset& proxy,
-            const wordHashSet& acceptField
-        );
-
-
         //- No copy construct
         ensightWrite(const ensightWrite&) = delete;
 
@@ -296,12 +298,6 @@ public:
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-#ifdef NoRepository
-    #include "ensightWriteTemplates.C"
-#endif
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
 #endif
 
 // ************************************************************************* //

src/functionObjects/utilities/ensightWrite/ensightWriteImpl.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -30,8 +30,9 @@ License
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 template<class Type>
-Foam::label Foam::functionObjects::ensightWrite::writeVolFields
+Foam::label Foam::functionObjects::ensightWrite::writeVolFieldsImpl
 (
+    ensightOutput::floatBufferType& scratch,
     const fvMeshSubset& proxy,
     const wordHashSet& acceptField
 )
@@ -58,6 +59,7 @@ Foam::label Foam::functionObjects::ensightWrite::writeVolFields
 
         ensightOutput::writeVolField<Type>
         (
+            scratch,
             os.ref(),
             field,
             ensMesh(),