What if not all nodes get 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)