Get V cycle working, add test

Author: ranjanan

src/AMG.jl

@@ -14,7 +14,9 @@ export poisson
 include("smoother.jl")
 
 include("multilevel.jl")
+export solve
 
 include("classical.jl")
+export ruge_stuben
 
 end # module

src/multilevel.jl

@@ -68,22 +68,20 @@ function solve{T}(ml::MultiLevel, b::Vector{T}; maxiter = 100,
         if length(ml.levels) == 1
             x = coarse_solver(ml.coarse_solver, A, b)
         else
-            x = __solve(cycle, ml, x, b, lvl, residuals)
+            x = __solve(cycle, ml, x, b, lvl)
         end
+        push!(residuals, norm(A*x - b))
     end
     x
 end
-function __solve{T}(v::V, ml, x::Vector{T}, b::Vector{T}, lvl, residuals)
+function __solve{T}(v::V, ml, x::Vector{T}, b::Vector{T}, lvl)
 
-    @show lvl
     A = ml.levels[lvl].A
     presmoother!(ml.presmoother, A, x, b)
 
     res = b - A * x
-    @show norm(res)
-    push!(residuals, norm(res))
-
     coarse_b = ml.levels[lvl].R * res
+    coarse_x = zeros(T, size(coarse_b))
 
     if lvl == length(ml.levels) - 1
         coarse_x = coarse_solver(ml.coarse_solver, ml.levels[end].A, coarse_b)

test/runtests.jl

@@ -44,7 +44,7 @@ end
 @testset "Coarse Solver" begin
 A = poisson(10)
 b = A * ones(10)
-@test sum(abs, AMG.coarse_solver(AMG.Pinv(), A, b) - ones(10)) < 1e-6
+@test sum(abs2, AMG.coarse_solver(AMG.Pinv(), A, b) - ones(10)) < 1e-6
 end
 
 @testset "Multilevel" begin
@@ -59,3 +59,11 @@ for i = 1:8
     @test nnz(ml.levels[i].A) == n[i]
 end
 end
+
+@testset "Solver" begin
+A = poisson(1000)
+A = float.(A)
+ml = ruge_stuben(A)
+x = solve(ml, A * ones(1000))
+@test sum(abs2, x - ones(1000)) < 1e-10
+end