ENH: add longer method names for accessing Matrix num rows/cols (#1391)

- in addition to m() and n(), provide Matrix mRows()/nRows(), nCols()
  methods.  These provide unambiguous access names.

  'mRows()' == for internal consistency with MatrixSpace.
  'nRows()' == a commonly used naming.

src/OpenFOAM/matrices/LUscalarMatrix/LUscalarMatrix.C

@@ -152,40 +152,38 @@ Foam::LUscalarMatrix::LUscalarMatrix
 
     if (Pstream::master(comm_))
     {
-        label mRows = m();
-        label nColumns = n();
-
         if (debug)
         {
-            Pout<< "LUscalarMatrix : size:" << mRows << endl;
+            const label numRows = m();
-            for (label rowI = 0; rowI < mRows; rowI++)
+            const label numCols = n();
-            {
-                const scalar* row = operator[](rowI);
 
-                Pout<< "cell:" << rowI << " diagCoeff:" << row[rowI] << endl;
+            Pout<< "LUscalarMatrix : size:" << numRows << endl;
+            for (label rowi = 0; rowi < numRows; ++rowi)
+            {
+                const scalar* row = operator[](rowi);
+
+                Pout<< "cell:" << rowi << " diagCoeff:" << row[rowi] << endl;
 
                 Pout<< "    connects to upper cells :";
-                for (label columnI = rowI+1; columnI < nColumns; columnI++)
+                for (label coli = rowi+1; coli < numCols; ++coli)
                 {
-                    if (mag(row[columnI]) > SMALL)
+                    if (mag(row[coli]) > SMALL)
                     {
-                        Pout<< ' ' << columnI << " (coeff:" << row[columnI]
+                        Pout<< ' ' << coli << " (coeff:" << row[coli] << ')';
-                            << ")";
                     }
                 }
                 Pout<< endl;
                 Pout<< "    connects to lower cells :";
-                for (label columnI = 0; columnI < rowI; columnI++)
+                for (label coli = 0; coli < rowi; ++coli)
                 {
-                    if (mag(row[columnI]) > SMALL)
+                    if (mag(row[coli]) > SMALL)
                     {
-                        Pout<< ' ' << columnI << " (coeff:" << row[columnI]
+                        Pout<< ' ' << coli << " (coeff:" << row[coli] << ')';
-                            << ")";
                     }
                 }
-                Pout<< endl;
+                Pout<< nl;
             }
-            Pout<< endl;
+            Pout<< nl;
         }
 
         pivotIndices_.setSize(m());

src/OpenFOAM/matrices/Matrix/Matrix.H

@@ -180,13 +180,13 @@ public:
 
     // Access
 
-        //- Return the number of rows
+        //- The number of rows
         inline label m() const noexcept;
 
-        //- Return the number of columns
+        //- The number of columns
         inline label n() const noexcept;
 
-        //- Return the number of elements in Matrix (m*n)
+        //- The number of elements in Matrix (m*n)
         inline label size() const;
 
         //- Return row/column sizes
@@ -483,6 +483,25 @@ public:
 
     // Housekeeping
 
+        //- The number of rows - same as m()
+        inline label mRows() const noexcept
+        {
+            return mRows_;
+        }
+
+        //- The number of rows - same as m()
+        inline label nRows() const noexcept
+        {
+            return mRows_;
+        }
+
+        //- The number of columns - same as n()
+        inline label nCols() const noexcept
+        {
+            return nCols_;
+        }
+
+
         //- Deprecated(2019-04) raw data pointer, const access
         //  \deprecated(2019-04) - use cdata() method
         const Type* FOAM_DEPRECATED_FOR(2019-04, "cdata() method") v() const