Just as a general comment: A program with nested loops is most likely not going to be performant on any way. It makes sense to re-think the algorithm, come up with a modified or different pattern, rather than trying to implement the exact algorithm line by line.
It may be worth checking that, because I am not sure if Gelly should have algorithms that don't perform well. On Thu, Sep 22, 2016 at 11:40 AM, Vasiliki Kalavri < vasilikikala...@gmail.com> wrote: > Hi Olga, > > when you use mapEdges() or mapVertices() with generics, Flink cannot > determine the type because of type erasure, like the exception says. That's > why we also provide methods that take the type information as a parameter. > You can use those to make the return type explicit. In your example, you > should do something like the following (line 41): > > final TypeInformation<Long> longType = BasicTypeInfo.LONG_TYPE_INFO; > final TypeInformation<Double> doubleType = BasicTypeInfo.DOUBLE_TYPE_INFO; > Graph<Long, String, Tuple3<Double, Long, Long>> graphOut = > graph.mapEdges(new InitializeEdges<Long, Double>(), new > TupleTypeInfo(longType, longType, > new TupleTypeInfo<Tuple3<Double, Long, Long>>(doubleType, > longType,longType))); > > Regarding the nested loops, I am almost sure that you will face problems if > you try to experiment with large datasets. I haven't looked into your code > yet, but according to the JIRA discussion, we've faced this problem before > and afaik, this is still an issue. > > Cheers, > -Vasia. > > On 22 September 2016 at 01:12, Olga Golovneva <melcha...@gmail.com> wrote: > > > Hi Vasia, > > > > I have uploaded these tests on github: > > https://github.com/OlgaGolovneva/MST/tree/master/tests > > > > I have also uploaded source code, but I'm still working on it: > > https://github.com/OlgaGolovneva/MST/tree/master/src > > > > >I think you cannot add attachments to the mailing list. Could you > upload > > >your example somewhere and post a link here? I'm actually surprised that > > >the while-loop works without problems. > > > > I have run the program on several simple tests, and I was going to try > > large datasets in the next few days. Please, let me know if this approach > > is wrong. > > > > Thanks, > > Olga > > > > On Wed, Sep 21, 2016 at 4:55 PM, Vasiliki Kalavri < > > vasilikikala...@gmail.com > > > wrote: > > > > > Hi Olga, > > > > > > On 21 September 2016 at 18:50, Olga Golovneva <melcha...@gmail.com> > > wrote: > > > > > > > Hi devs, > > > > > > > > I was working on (FLINK-1526) "Add Minimum Spanning Tree library > > method > > > > and example" issue. I've developed (Java) code that implements > > > distributed > > > > Boruvka's algorithm in Gelly library. I've run several tests and it > > seems > > > > to work fine, although I didn't test it on extremely large input > graphs > > > > yet, and I'm also trying to optimize my code. > > > > Particularly, I have two main issues: > > > > > > > > 1. Nested loops. > > > > I have to use nested loops, and I do not see the way to avoid them. > As > > > > they are currently not supported, I'm using Bulk Iterations inside a > > > > "classic" while loop. I've included in attachment simple example > > > > MyNestedIterationExample that shows this issue. > > > > > > > > > > I think you cannot add attachments to the mailing list. Could you > upload > > > your example somewhere and post a link here? I'm actually surprised > that > > > the while-loop works without problems. > > > > > > > > > > > > > > 2. For some reason I cannot create class that works with types with > > > > generic variables in Tuple2(or Tuple3), thus my code does not support > > > > generic types. I also included simple example MyTuple3Example. Here > is > > > the > > > > Exception I get: > > > > "Exception in thread "main" org.apache.flink.api.common.functions. > > > InvalidTypesException: > > > > Type of TypeVariable 'EV' in 'class org.apache.flink.graph. > > > > examples.MyTuple3Example$InitializeEdges' could not be determined. > > This > > > > is most likely a type erasure problem. The type extraction currently > > > > supports types with generic variables only in cases where all > variables > > > in > > > > the return type can be deduced from the input type(s)." > > > > > > > > > > Can you upload this example and link to it too? > > > > > > Thanks, > > > -Vasia. > > > > > > > > > > > > > > I would really appreciate if someone could explain me know how to > avoid > > > > this Exception. Otherwise, I could submit my code for testing. > > > > > > > > Best regards, > > > > Olga Golovneva > > > > > > > > > >
