Merge pull request #1 from JuliaLinearAlgebra/h-larsson-dbg

Sharpen idrs-pre test

Author: h-larsson

test/idrs.jl

@@ -51,13 +51,13 @@ end
     @test history.isconverged
     @test norm(A * x - b) / norm(b) ≤ reltol
 
-    Apre = lu(A)
+    Apre = lu(droptol!(copy(A), 0.1)) # inexact preconditioner
     xpre, historypre = idrs(A, b, Pl = Apre, log=true)
     @test historypre.isconverged
     @test norm(A * xpre - b) / norm(b) ≤ reltol
 
     @test isapprox(x, xpre, rtol = 1e-3)
-    @test historypre.iters < history.iters
+    @test historypre.iters < 0.5history.iters
 
 end