Add print method

Author: ranjanan

src/classical.jl

@@ -26,7 +26,7 @@ function ruge_stuben(A::SparseMatrixCSC;
             break
         end
     end
-    levels
+    MultiLevel(levels)
 end
 
 function extend_heirarchy!(levels::Vector{Level}, strength, CF, A)

src/multilevel.jl

@@ -3,3 +3,37 @@ struct Level{Ti,Tv}
     P::SparseMatrixCSC{Ti,Tv}
     R::SparseMatrixCSC{Ti,Tv}
 end
+
+struct MultiLevel{L, S}
+    levels::Vector{L}
+    coarse_solver::S
+end
+
+abstract type CoarseSolver end
+struct Pinv <: CoarseSolver
+end
+MultiLevel(l::Vector{Level}; coarse_solver = Pinv()) =
+    MultiLevel(l, coarse_solver)
+
+function Base.show(io::IO, ml::MultiLevel)
+    op = operator_complexity(ml.levels)
+    g = grid_complexity(ml.levels)
+    c = ml.coarse_solver
+    str = """
+    Multilevel Solver
+    -----------------
+    Operator Complexity: $op
+    Grid Complexity: $g
+    No. of Levels: $(size(ml.levels, 1))
+    Coarse Solver: $c
+    """
+    print(io, str)
+end
+
+function operator_complexity(ml::Vector{Level})
+    sum(nnz(level.A) for level in ml) / nnz(ml[1].A)
+end
+
+function grid_complexity(ml::Vector{Level})
+    sum(size(level.A, 1) for level in ml) / size(ml[1].A, 1)
+end