STYLE: adjust globalIndex/CompactListList overflow reporting

- report location with previous good offset and the new count that
  would cause overflow. Simpler to report and the (very long) list
  of input sizes is not particularly useful for diagnostics either.

ENH: add globalIndex comparison operators

- for outputting lists of globalIndex

src/OpenFOAM/containers/CompactLists/CompactListList/CompactListList.C

@@ -35,16 +35,25 @@ template<class T>
 void Foam::CompactListList<T>::reportOverflowAndExit
 (
     const label idx,
-    const labelUList& localLens
+    const label prevOffset,
+    const label count
 )
 {
+    if (idx < 0)
+    {
+        // No overflow tagged
+        return;
+    }
+
     FatalErrorInFunction
         << "Overflow : sum of sizes exceeds labelMax ("
         << labelMax << ") after index " << idx;
 
-    if (!localLens.empty())
+    if (prevOffset >= 0 && count >= 0)
     {
-        FatalError << " of " << flatOutput(localLens);
+        FatalError
+            << " while trying to add (" << count
+            << ") to offset (" << prevOffset << ")";
     }
 
     FatalError
@@ -76,12 +85,14 @@ Foam::CompactListList<T> Foam::CompactListList<T>::pack_impl
 
         for (label i = 0; i < len; ++i)
         {
+            const label count = lists[i].size();
+
             newOffsets[i] = total;
-            total += lists[i].size();
+            total += count;
 
             if (checkOverflow && total < newOffsets[i])
             {
-                reportOverflowAndExit(i);
+                reportOverflowAndExit(i, newOffsets[i], count);
             }
         }
         newOffsets[len] = total;
@@ -162,12 +173,14 @@ Foam::label Foam::CompactListList<T>::resize_offsets
 
         for (label i = 0; i < len; ++i)
         {
+            const label count = listSizes[i];
+
             offsets_[i] = total;
-            total += listSizes[i];
+            total += count;
 
             if (checkOverflow && total < offsets_[i])
             {
-                reportOverflowAndExit(i, listSizes);
+                reportOverflowAndExit(i, offsets_[i], count);
             }
         }
 
@@ -229,8 +242,8 @@ Foam::label Foam::CompactListList<T>::maxNonLocalSize(const label rowi) const
     {
         if (i != rowi)
         {
-            const label localLen = (offsets_[i+1] - offsets_[i]);
+            const label count = (offsets_[i+1] - offsets_[i]);
-            maxLen = max(maxLen, localLen);
+            maxLen = max(maxLen, count);
         }
     }
 

src/OpenFOAM/containers/CompactLists/CompactListList/CompactListList.H

@@ -82,11 +82,12 @@ class CompactListList
 
     // Private Member Functions
 
-        //- Report overflow at specified index
+        //- Report overflow at specified (non-negative) index
         static void reportOverflowAndExit
         (
             const label idx,
-            const labelUList& listSizes = labelUList::null()
+            const label prevOffset = -1,  // The last valid offset value
+            const label count = 0         // The count to add to prevOffset
         );
 
         //- Construct by packing together the list of lists

src/OpenFOAM/parallel/globalIndex/globalIndex.C

@@ -34,16 +34,25 @@ License
 void Foam::globalIndex::reportOverflowAndExit
 (
     const label idx,
-    const labelUList& localLens
+    const label prevOffset,
+    const label count
 )
 {
+    if (idx < 0)
+    {
+        // No overflow tagged
+        return;
+    }
+
     FatalErrorInFunction
         << "Overflow : sum of sizes exceeds labelMax ("
         << labelMax << ") after index " << idx;
 
-    if (!localLens.empty())
+    if (prevOffset >= 0 && count >= 0)
     {
-        FatalError << " of " << flatOutput(localLens);
+        FatalError
+            << " while trying to add (" << count
+            << ") to offset (" << prevOffset << ")";
     }
 
     FatalError
@@ -70,27 +79,29 @@ Foam::globalIndex::calcRange
     }
 
     const label myProci = UPstream::myProcNo(comm);
-    const labelList localLens = UPstream::allGatherValues(localSize, comm);
+    const labelList counts = UPstream::allGatherValues(localSize, comm);
 
     if (checkOverflow)
     {
-        const label len = localLens.size();
+        const label len = counts.size();
 
         label start = 0;
 
         for (label i = 0; i < len; ++i)
         {
+            const label count = counts[i];
+
             if (i == myProci)
             {
                 myRange.start() = start;
             }
 
             const label prev = start;
-            start += localLens[i];
+            start += count;
 
             if (start < prev)
             {
-                reportOverflowAndExit(i, localLens);
+                reportOverflowAndExit(i, prev, count);
             }
         }
     }
@@ -98,8 +109,8 @@ Foam::globalIndex::calcRange
     {
         // std::accumulate
         // (
-        //     localLens.cbegin(),
+        //     counts.cbegin(),
-        //     localLens.cbegin(myProci),
+        //     counts.cbegin(myProci),
         //     label(0)
         // );
 
@@ -107,7 +118,7 @@ Foam::globalIndex::calcRange
 
         for (label i = 0; i < myProci; ++i)
         {
-            start += localLens[i];
+            start += counts[i];
         }
         myRange.start() = start;
     }
@@ -133,27 +144,28 @@ Foam::globalIndex::calcOffset
     }
 
     const label myProci = UPstream::myProcNo(comm);
-    const labelList localLens = UPstream::allGatherValues(localSize, comm);
+    const labelList counts = UPstream::allGatherValues(localSize, comm);
 
     if (checkOverflow)
     {
-        const label len = localLens.size();
+        const label len = counts.size();
 
         label start = 0;
 
         for (label i = 0; i < len; ++i)
         {
+            const label count = counts[i];
             if (i == myProci)
             {
                 myOffset = start;
             }
 
             const label prev = start;
-            start += localLens[i];
+            start += count;
 
             if (start < prev)
             {
-                reportOverflowAndExit(i, localLens);
+                reportOverflowAndExit(i, prev, count);
             }
         }
     }
@@ -161,8 +173,8 @@ Foam::globalIndex::calcOffset
     {
         // std::accumulate
         // (
-        //     localLens.cbegin(),
+        //     counts.cbegin(),
-        //     localLens.cbegin(myProci),
+        //     counts.cbegin(myProci),
         //     label(0)
         // );
 
@@ -170,7 +182,7 @@ Foam::globalIndex::calcOffset
 
         for (label i = 0; i < myProci; ++i)
         {
-            start += localLens[i];
+            start += counts[i];
         }
         myOffset = start;
     }
@@ -182,13 +194,13 @@ Foam::globalIndex::calcOffset
 Foam::labelList
 Foam::globalIndex::calcOffsets
 (
-    const labelUList& localLens,
+    const labelUList& counts,
     const bool checkOverflow
 )
 {
     labelList values;
 
-    const label len = localLens.size();
+    const label len = counts.size();
 
     if (len)
     {
@@ -197,12 +209,13 @@ Foam::globalIndex::calcOffsets
         label start = 0;
         for (label i = 0; i < len; ++i)
         {
+            const label count = counts[i];
             values[i] = start;
-            start += localLens[i];
+            start += count;
 
             if (checkOverflow && start < values[i])
             {
-                reportOverflowAndExit(i, localLens);
+                reportOverflowAndExit(i, values[i], count);
             }
         }
         values[len] = start;
@@ -215,13 +228,13 @@ Foam::globalIndex::calcOffsets
 Foam::List<Foam::labelRange>
 Foam::globalIndex::calcRanges
 (
-    const labelUList& localLens,
+    const labelUList& counts,
     const bool checkOverflow
 )
 {
     List<labelRange> values;
 
-    const label len = localLens.size();
+    const label len = counts.size();
 
     if (len)
     {
@@ -230,12 +243,18 @@ Foam::globalIndex::calcRanges
         label start = 0;
         for (label i = 0; i < len; ++i)
         {
-            values[i].reset(start, localLens[i]);
+            const label count = counts[i];
-            start += localLens[i];
+            values[i].reset(start, count);
+            start += count;
 
-            if (checkOverflow && start < values[i].start())
+            if
+            (
+                checkOverflow
+             && (start < values[i].start())
+             && (i < len-1)  // Do not check the one beyond the end range
+            )
             {
-                reportOverflowAndExit(i, localLens);
+                reportOverflowAndExit(i, values[i].start(), count);
             }
         }
     }
@@ -328,11 +347,11 @@ void Foam::globalIndex::reset
 
     if (len)
     {
-        labelList localLens;
+        labelList counts;
 
         if (parallel && UPstream::parRun())  // or UPstream::is_parallel(comm)
         {
-            localLens = UPstream::allGatherValues(localSize, comm);
+            counts = UPstream::allGatherValues(localSize, comm);
         }
         else
         {
@@ -340,11 +359,11 @@ void Foam::globalIndex::reset
             // TBD: check for (proci >= 0) ?
             const auto proci = UPstream::myProcNo(comm);
 
-            localLens.resize(len, Zero);
+            counts.resize(len, Zero);
-            localLens[proci] = localSize;
+            counts[proci] = localSize;
         }
 
-        reset(localLens, true);  // checkOverflow = true
+        reset(counts, true);  // checkOverflow = true
     }
     else
     {
@@ -356,11 +375,11 @@ void Foam::globalIndex::reset
 
 void Foam::globalIndex::reset
 (
-    const labelUList& localLens,
+    const labelUList& counts,
     const bool checkOverflow
 )
 {
-    const label len = localLens.size();
+    const label len = counts.size();
 
     if (len)
     {
@@ -369,12 +388,13 @@ void Foam::globalIndex::reset
         label start = 0;
         for (label i = 0; i < len; ++i)
         {
+            const label count = counts[i];
             offsets_[i] = start;
-            start += localLens[i];
+            start += count;
 
             if (checkOverflow && start < offsets_[i])
             {
-                reportOverflowAndExit(i, localLens);
+                reportOverflowAndExit(i, offsets_[i], count);
             }
         }
         offsets_[len] = start;
@@ -468,8 +488,8 @@ Foam::label Foam::globalIndex::maxNonLocalSize(const label proci) const
     {
         if (i != proci)
         {
-            const label localLen = (offsets_[i+1] - offsets_[i]);
+            const label count = (offsets_[i+1] - offsets_[i]);
-            maxLen = max(maxLen, localLen);
+            maxLen = max(maxLen, count);
         }
     }
 
@@ -506,17 +526,17 @@ Foam::labelRange Foam::globalIndex::back() const
 }
 
 
-// * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
+// * * * * * * * * * * * * * * * IOstream Operators  * * * * * * * * * * * * //
 
 Foam::Istream& Foam::operator>>(Istream& is, globalIndex& gi)
 {
-    return is >> gi.offsets_;
+    return is >> gi.offsets();
 }
 
 
 Foam::Ostream& Foam::operator<<(Ostream& os, const globalIndex& gi)
 {
-    return os << gi.offsets_;
+    return os << gi.offsets();
 }
 
 

src/OpenFOAM/parallel/globalIndex/globalIndex.H

@@ -83,11 +83,12 @@ class globalIndex
             DynamicList<label>& validBins
         );
 
-        //- Report overflow at specified index
+        //- Report overflow at specified (non-negative) index
         static void reportOverflowAndExit
         (
             const label idx,
-            const labelUList& localLens = labelUList::null()
+            const label prevOffset = -1,  // The last valid offset value
+            const label count = 0         // The count to add to prevOffset
         );
 
 public:
@@ -122,7 +123,7 @@ public:
         //- No communication required
         inline explicit globalIndex(labelList&& listOffsets);
 
-        //- Copy construct from a list of sizes.
+        //- Construct from a list of sizes and calculate the offsets.
         //- No communication required
         inline globalIndex
         (
@@ -265,12 +266,12 @@ public:
             const bool parallel = UPstream::parRun()  //!< use parallel comms
         );
 
-        //- Reset from list of local sizes,
+        //- Reset offsets from a list of local sizes,
         //- with optional check for label overflow.
         //- No communication required
         void reset
         (
-            const labelUList& localLens,
+            const labelUList& counts,
             const bool checkOverflow = false
         );
 
@@ -307,6 +308,9 @@ public:
             const label comm = UPstream::worldComm  //!< communicator
         );
 
+        //- Reset the globalIndex. Same as copy assignment.
+        inline void reset(const globalIndex& gi);
+
         //- Alter local size for given processor
         void setLocalSize(const label proci, const label len);
 
@@ -504,7 +508,7 @@ public:
         //- with optional check for label overflow
         static labelList calcOffsets
         (
-            const labelUList& localLens,
+            const labelUList& counts,
             const bool checkOverflow = false
         );
 
@@ -521,7 +525,7 @@ public:
         //- with optional check for label overflow
         static List<labelRange> calcRanges
         (
-            const labelUList& localLens,
+            const labelUList& counts,
             const bool checkOverflow = false
         );
 
@@ -955,6 +959,27 @@ public:
         ) const;
 
 
+    // Member Operators
+
+        //- Compare for equality - uses the offsets
+        bool operator==(const globalIndex& rhs) const
+        {
+            return (this->offsets() == rhs.offsets());
+        }
+
+        //- Compare for inequality - uses the offsets
+        bool operator!=(const globalIndex& rhs) const
+        {
+            return !(*this == rhs);
+        }
+
+        //- Compare for less-than - uses the offsets
+        bool operator<(const globalIndex& rhs) const
+        {
+            return (this->offsets() < rhs.offsets());
+        }
+
+
     // IOstream Operators
 
         friend Istream& operator>>(Istream& is, globalIndex& gi);

src/OpenFOAM/parallel/globalIndex/globalIndexI.H

@@ -467,6 +467,16 @@ inline void Foam::globalIndex::reset
 }
 
 
+inline void Foam::globalIndex::reset(const globalIndex& rhs)
+{
+    if (this == &rhs)
+    {
+        return;  // Self-assignment is a no-op
+    }
+    this->offsets_ = rhs.offsets_;
+}
+
+
 // * * * * * * * * * * * * * * * * Iterators * * * * * * * * * * * * * * * * //
 
 inline Foam::globalIndex::const_iterator::

src/OpenFOAM/parallel/globalIndex/globalIndexTemplates.C

@@ -49,12 +49,14 @@ Foam::globalIndex::calcListOffsets
         label start = 0;
         for (label i = 0; i < len; ++i)
         {
+            const label count = lists[i].size();
+
             values[i] = start;
-            start += lists[i].size();
+            start += count;
 
             if (checkOverflow && start < values[i])
             {
-                reportOverflowAndExit(i);
+                reportOverflowAndExit(i, values[i], count);
             }
         }
         values[len] = start;
@@ -1005,12 +1007,12 @@ OutputContainer Foam::globalIndex::scatter
         // The globalIndex might be correct on master only,
         // so scatter local sizes to ensure consistency
 
-        const label localLen
+        const label count
         (
             UPstream::listScatterValues<label>(this->localSizes(), comm)
         );
 
-        OutputContainer localData(localLen);
+        OutputContainer localData(count);
         this->scatter(allData, localData, tag, commsType, comm);
 
         return localData;