Norm of NxNx1 grid gives poison in new version of Carpet

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Issue #617 closed
Ian Hinder created an issue

I am having a problem with a 2D Carpet unigrid simulation with NxNx1 grid points in each direction. I have 0 boundary points and 0 ghost points in the z direction. The norm2 and other norms computed by CarpetIOBasic and CarpetIOScalar are showing poison. The same happens if I use one boundary point and one ghost point. The important feature is that zmin = zmax. If I make zmax = zmin + dz, then the norms are fine. This works fine in the git version of Carpet - it seems to be a regression in the Mercurial version.

Parameter file is attached.

Keyword: regression

Comments (5)

  1. Erik Schnetter
    • removed comment

    Note: Your parameter file has 1 boundary point in the z direction, not 0, i.e. your grid should be NxNx3.

    However, this doesn't change things. Since 3D norms are ill-defined in this case (the 3D volume of the domain is 0), Carpet recognises this and switches to a 2D interpretation. Maybe this is broken.

  2. Erik Schnetter
    • changed status to open
    • removed comment

    As I mention above, your domain extent in the z direction is 3; you have 1 interior point, and 1 boundary point on every face. You can set boundary_size_z_{lower|upper} to 0 if you truly want an NxNx1 domain. Note that you still either need the shiftout to be 1 for both upper and lower z face, or you need to declare this as internal boundary.

    Please try this patch to correct the problem I mention above:

    $ hg diff . diff -r 682146b9a530 Carpet/CarpetReduce/src/mask_coords.c --- a/Carpet/CarpetReduce/src/mask_coords.c Sat Dec 10 19:21:28 2011 -0500 +++ b/Carpet/CarpetReduce/src/mask_coords.c Mon Dec 12 14:27:20 2011 -0500 @@ -134,8 +134,12 @@ directly on the boundary the weight 1/2 */ if (! is_staggered[2*d+f]) {

    + /* Since we are going to cut off 1/2 at each boundary, the + domain size must be at least 1 to begin with */ + assert (int_points[d] >= 1); + /* Check whether the domain is empty */ - if (int_points[d] == 0) { + if (int_points[d] == 1) {

    /* The domain is empty. The correct thing to do would be to set the weights to 0. But this is boring, because

  3. Ian Hinder reporter
    • changed status to resolved
    • removed comment

    It was committed already:

    Author: Erik Schnetter <> Date: Wed Jan 11 16:02:48 2012 -0500

    CarpetReduce: Set up weight function correctly for 2D domains

    I have just tried it, and it works now.

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