From 9ebe06e9b747ee507b503d302b5ea9ea4083ad41 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth
(WB 2000/05/16)
+ Changed: The computation of the Jacobian matrices in the
+ FEValues
class is now done more
+ efficiently. The speedup is in the range of a factor of 40 for
+ 3D.
+
+ (John Burnell, WB 2000/05/16)
+
+ Changed: the
+ MatrixTools::apply_boundary_values
+ now uses a much faster algorithm when using on matrices with
+ symmetric sparsity patterns. On the other hand, it does no more
+ eliminate whole rows when a matrix has a non-symmetric sparsity
+ pattern, or if the user (through a new flag) tells the function
+ that this is not necessary, for example if the matrix itself is
+ non-symmetric.
+
+ For symmetric sparsity patterns, the algorithm now eliminates + each boundary value in O(m*log(m)) steps instead of + O(N*log(m)), where N=number of rows of the matrix, and m=number + of entries per row. Note that m is roughly constant, + irrespective of N, so the old algorithm became slower with + finer grids, while the new one is O(1) for each boundary degree + of freedom. +
+ ++ (John Burnell, WB 2000/05/17) +