Merge pull request #253 from platawiec/idrs-res

fix idrs! when near solution

Author: mschauer

src/idrs.jl

@@ -84,8 +84,9 @@ function idrs_method!(log::ConvergenceHistory, X, A, C::T,
         T_s = zero(R)
     end
 
-    if normR <= tol           # Initial guess is a good enough solution
-        return X, ConvergenceHistory(0<= res[end] < tol, tol, length(res), res)
+    if normR <= tol # Initial guess is a good enough solution
+        setconv(log, 0<=normR<tol)
+        return X
     end
 
     Z = zero(C)
@@ -159,7 +160,6 @@ function idrs_method!(log::ConvergenceHistory, X, A, C::T,
             push!(log, :resnorm, normR)
             verbose && @printf("%3d\t%1.2e\n",iter,normR)
             if normR < tol || iter == maxiter
-                shrink!(log)
                 setconv(log, 0<=normR<tol)
                 return X
             end

test/idrs.jl

@@ -44,4 +44,17 @@ end
     @test history.iters == 2
     @test length(history[:resnorm]) == 2
 end
+
+@testset "Near solution (#222)" begin
+    x = rand(5)
+    A = rand(5, 5)
+    b = rand(5)
+
+    x, history = idrs!(x, A, b, log=true)
+    x_new = copy(x)
+    x_new, history = idrs!(x_new, A, b, log=true)
+
+    @test x_new ≈ x
+end
+
 end