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[Adam Getchell <>]

Sebastien,

Thank you!

In hindsight, it makes sense that the facet flip results in an edge which violates the Delaunay condition.

Regards,

Adam

On Wed, Feb 4, 2015 at 11:32 PM, Sebastien Loriot (GeometryFactory) <> wrote:

If you flip some edges in a Delaunay triangulation, the is_valid will tell you that the triangulation is no longer Delaunay.
Use the dt.tds().is_valid() instead.

Sebastien.


On 02/05/2015 07:23 AM, Adam Getchell wrote:

I've also done tests on flips of (2,2) simplices, with the same results
(triangulation validity violated), except that they don't also violate
my time foliation. The code currently on GitHub reflects the flips on
(2,2) simplices.

On Wed, Feb 4, 2015 at 10:07 PM, Adam Getchell <

<mailto:adam.getchell@gmail.com>> wrote:

    Hello all,

    For the following code:

    void make_23_move(Delaunay* D3, std::vector<Cell_handle>* three_one,
                          std::vector<Cell_handle>* two_two) {
       // Pick a random (2,2)
       unsigned choice = generate_random_unsigned(three_one->size());
       std::cout << "We're picking (3,1) vector " << choice << std::endl;
       Cell_handle to_be_moved = (*three_one)[choice];
       for (size_t i = 0; i < 4; i++) {
         if (D3->flip(to_be_moved, i)) {
           // Delaunay::flip_flippable(to_be_moved,0)
           std::cout << "Facet " << i << " was flippable." << std::endl;
           break;
         } else {
           std::cout << "Facet " << i << " was not flippable." << std::endl;
         }
       }
    }

    From:
    https://github.com/acgetchell/CDT-plusplus/blob/master/src/S3ErgodicMoves.h

    Invoked in the test:

    TEST_F(S3ErgodicMoves, MakeA23Move) {
       unsigned number_of_vertices_before = T.number_of_vertices();
       unsigned N3_31_before = three_one.size();
       unsigned N3_22_before = two_two.size();
       unsigned N3_13_before = one_three.size();
       std::cout << "Number of (2,2) simplices before = " << N3_22_before
                 << std::endl;
       make_23_move(&T, &three_one, &two_two);

       // Now look at changes
       reclassify_3_simplices(&T, &three_one, &two_two, &one_three);
       unsigned N3_31_after = three_one.size();
       unsigned N3_22_after = two_two.size();
       unsigned N3_13_after = one_three.size();

       EXPECT_TRUE(T.is_valid())
       << "Triangulation is invalid.";

    From:
    https://github.com/acgetchell/CDT-plusplus/blob/master/unittests/S3ErgodicMovesTest.cpp

    I've run these tests a couple dozen times, and every time there is a
    flippable edge the triangulation is invalidated, e.g.:

    Repeating all tests (iteration 9) . . .


    Note: Google Test filter = S3ErgodicMoves.MakeA23Move

    [==========] Running 1 test from 1 test case.

    [----------] Global test environment set-up.

    [----------] 1 test from S3ErgodicMoves

    [ RUN      ] S3ErgodicMoves.MakeA23Move

    Generating universe ...

    Pass #1

    Fixing foliation....

    Pass #2

    Fixing foliation....

    Pass #3

    Fixing foliation....

    Pass #4

    Fixing foliation....

    Pass #5

    Fixing foliation....

    Classifying simplices....

    Valid foliation: true

    Delaunay triangulation has 95251 cells.

    There are 29713 (3,1) simplices and 35628 (2,2) simplices and 29910
    (1,3) simplices.

    Number of (2,2) simplices before = 35628

    Random number is 27858

    We're picking (3,1) vector 27858

    Facet 0 was flippable.

    Classifying simplices....

    ../unittests/S3ErgodicMovesTest.cpp:82: Failure

    Value of: T.is_valid()

       Actual: false

    Expected: true

    Triangulation is invalid.

    [  FAILED  ] S3ErgodicMoves.MakeA23Move (2229 ms)

    [----------] 1 test from S3ErgodicMoves (2229 ms total)


    [----------] Global test environment tear-down

    [==========] 1 test from 1 test case ran. (2229 ms total)

    [  PASSED  ] 0 tests.

    [  FAILED  ] 1 test, listed below:

    [  FAILED  ] S3ErgodicMoves.MakeA23Move


      1 FAILED TEST



    --
    Adam Getchell

    about.me/adamgetchell <http://about.me/adamgetchell>
    "Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu




--
Adam Getchell
about.me/adamgetchell <http://about.me/adamgetchell>
"Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu

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Adam Getchell

about.me/adamgetchell

"Invincibility is in oneself, vulnerability in the opponent." -- Sun Tzu