Merge pull request #41 from tensor4all/40-estimatetrueerror-does-not-stop-if-the-error-is-close-to-machine-precision

Fixed possible infinite loop in estimatetrueerror

Author: shinaoka

src/globalsearch.jl

@@ -80,7 +80,9 @@ function _floatingzone(
             )
             err = vec(abs.(exactdata .- prediction))
             pivot[ipos] = argmax(err)
-            maxerror = maximum(err)
+            # In RHS, we compare the maximum of the error vector with the current maxerror
+            # to make sure that the error does not decrease even if maxerror is close to machine precision.
+            maxerror = max(maximum(err), maxerror)
         end
 
         if maxerror == prev_maxerror || maxerror > earlystoptol # early stop

test/test_globalsearch.jl

@@ -32,6 +32,6 @@ import QuanticsGrids as QD
     pivoterrors = TCI.estimatetrueerror(TCI.TensorTrain(tci), f)
 
     errors = [e for (_, e) in pivoterrors] 
-    @test all([abs(f(p) - tci(p)) for (p, _) in pivoterrors] .== errors)
+    @test [abs(f(p) - tci(p)) for (p, _) in pivoterrors] ≈ errors
     @test all(errors[1:end-1] .>= errors[2:end]) # check if errors are sorted in descending order
 end