fix in restrictions in case the problem does not solve for the full sol vector

Author: chmerdon

Project.toml

@@ -5,6 +5,7 @@ authors = ["Christian Merdon <merdon@wias-berlin.de>", "Patrick Jaap <patrick.ja
 
 [deps]
 BlockArrays = "8e7c35d0-a365-5155-bbbb-fb81a777f24e"
+CatViews = "81a5f4ea-a946-549a-aa7e-2a7f63a27d31"
 ChunkSplitters = "ae650224-84b6-46f8-82ea-d812ca08434e"
 CommonSolve = "38540f10-b2f7-11e9-35d8-d573e4eb0ff2"
 DiffResults = "163ba53b-c6d8-5494-b064-1a9d43ac40c5"
@@ -29,6 +30,7 @@ UnicodePlots = "b8865327-cd53-5732-bb35-84acbb429228"
 [compat]
 Aqua = "0.8"
 BlockArrays = "1.7.0"
+CatViews = "1.0.0"
 ChunkSplitters = "3.1.2"
 CommonSolve = "0.2"
 DiffResults = "1"

src/ExtendableFEM.jl

@@ -7,6 +7,7 @@ module ExtendableFEM
 
 using ChunkSplitters: chunks
 using BlockArrays: BlockMatrix, BlockVector, Block, blocks, axes
+using CatViews: CatView
 using CommonSolve: CommonSolve
 using DiffResults: DiffResults
 using DocStringExtensions: DocStringExtensions, TYPEDEF, TYPEDSIGNATURES

src/solvers.jl

@@ -253,6 +253,9 @@ function solve_linear_system!(A, b, sol, soltemp, residual, linsolve, unknowns,
             b_unrestricted = residual.entries
         end
 
+        ## restrictions only involve the blocks coressponding to the unknowns and not necessarily the full sol.entries
+        sol_freedofs = CatView([view(sol[u]) for u in unknowns]...)
+
         if length(PD.restrictions) == 0
             if linsolve_needs_matrix
                 linsolve.A = A_unrestricted
@@ -273,7 +276,7 @@ function solve_linear_system!(A, b, sol, soltemp, residual, linsolve, unknowns,
 
                 ## we need to add the (initial) solution to the rhs, since we work with the residual equation
                 for (B, rhs) in zip(restriction_matrices, restriction_rhs)
-                    rhs .-= B'sol.entries
+                    rhs .-= B'sol_freedofs
                 end
 
                 total_size = sum(block_sizes)