Merge pull request #25 from ranjanan/no_agg

Fix Aggregation Operator construction when some nodes aren't aggregated.

Author: ranjanan

src/aggregate.jl

@@ -93,9 +93,19 @@ function aggregation(::StandardAggregation, S)
     y = y[1:next_aggregate]
     M,N = (n, next_aggregate)
 
-    Tp = collect(1:n+1)
-    x .= x .+ 1
-    Tx = ones(eltype(S), length(x))
+    # Some nodes not aggregated
+    if minimum(x) == -1
+        mask = x .!= -1
+        I = collect(1:n)[mask]
+        J = x[mask] + 1
+        V = ones(eltype(S), length(J))
+        AggOp = sparse(J,I,V,N,M)
+    else
+        Tp = collect(1:n+1)
+        x .= x .+ 1
+        Tx = ones(eltype(S), length(x))
+        AggOp = SparseMatrixCSC(N, M, Tp, x, Tx)
+    end
 
-    SparseMatrixCSC(N, M, Tp, x, Tx)
+    AggOp
 end

src/aggregation.jl

@@ -86,8 +86,11 @@ function fit_candidates(AggOp, B, tol = 1e-10)
 
     R = zeros(eltype(B), n_coarse)
     Qx = zeros(eltype(B), nnz(A))
-
-    copy!(Qx, B)
+   
+    # copy!(Qx, B)
+    for i = 1:size(Qx, 1)
+        Qx[i] = B[i]
+    end
     # copy!(A.nzval, B)
     for i = 1:n_col
         for j in nzrange(A,i)

src/strength.jl

@@ -118,9 +118,9 @@ function strength_of_connection{T}(s::SymmetricStrength{T}, A, bsr_flag = false)
     dropzeros!(S)
 
     # S.nzval .= abs.(S.nzval)
-    #for i = 1:size(S.nzval, 1)
-    #     S.nzval[i] = abs(S.nzval[i])
-    #end
+    # for i = 1:size(S.nzval, 1)
+    #      S.nzval[i] = abs(S.nzval[i])
+    # end
 
     scale_cols_by_largest_entry!(S)
 

test/onetoall.jld

@@ -241,28 +241,31 @@ end
 
 @testset "Symmetric Strength of Connection" begin
 
-        test_symmetric_soc()
+    test_symmetric_soc()
 end
 
 @testset "Standard Aggregation" begin
 
-        test_standard_aggregation()
+    test_standard_aggregation()
 end
 
 @testset "Fit Candidates" begin
-        test_fit_candidates()
+    test_fit_candidates()
 end
 
 @testset "Approximate Spectral Radius" begin
-        test_approximate_spectral_radius()
+    test_approximate_spectral_radius()
 end
 end
 
 @testset "Gauss Seidel" begin
-        test_gauss_seidel()
+    test_gauss_seidel()
 end
 
 @testset "Jacobi Prolongation" begin
-        test_jacobi_prolongator()
+    test_jacobi_prolongator()
+end
+
+# Issue #24
+nodes_not_agg()
 end
-end

test/runtests.jl

@@ -311,4 +311,12 @@ function test_jacobi_prolongator()
     x = smooth_prolongator(JacobiProlongation(4/3), A, T, 1, 1)
     ref = load("ref_R.jld")["G"]
     @test sum(abs2, x - ref) < 1e-6
-end
+end
+
+# Issue #24
+function nodes_not_agg()
+    A = load("onetoall.jld")["G"]
+    ml = smoothed_aggregation(A)
+    @test size(ml.levels[2].A) == (11,11)
+    @test size(ml.final_A) == (2,2)
+end