Hi again.

I'm testing GPU simulations against CPU ones. I´ve modified only the size of the k-space for the same configuration in all tests. I´ve tried 128, 256, 512 and 1024, apart from other sizes to test non-power of two yield. I´m doing this to prove my boss that we should buy some CUDA compatible hardware, so it is just orientative.

Simulations for GPU at 128, 256, 512 and 1024 went right, but for CPU only, MATLAB crashes at 1024 with this message:

```
Running k-space simulation...
WARNING: visualisation plot scale may not be optimal for given source
dt: 20ns, t_end: 96.54us, time steps: 4828
input grid size: 1024 by 1024 pixels (102.4 by 102.4mm)
maximum supported frequency: 7.5MHz
smoothing p0 distribution...
smoothing density distribution...
calculating Delaunay triangulation...
??? Error using ==> qhullmx
While executing: | qhull d Qt Qbb Qc
Options selected for Qhull 2003.1 2003/12/30:
delaunay Qtriangulate Qbbound-last Qcoplanar-keep _pre-merge
_zero-centrum Pgood Qinterior-keep _max-width 0.1 Error-roundoff 1.4e-016
_one-merge 9.9e-016 Visible-distance 2.8e-016 U-coplanar-distance 2.8e-016
Width-outside 5.7e-016 _wide-facet 1.7e-015
Last point added to hull was p276113.
Last merge was #1742388.
Qhull has finished constructing the hull.
At error exit:
precision problems (corrected unless 'Q0' or an error)
1742388
coplanar horizon facets for new vertices
1
degenerate hyperplanes recomputed with gaussian elimination
1
nearly singular or axis-parallel hyperplanes
Error in ==> delaunayn at 117
t = qhullmx(x', 'd ', opt);
Error in ==> gridDataFast at 55
tri = delaunayn([x y]);
Error in ==> kspaceFirstOrder2D at 952
[zi del_tri] = gridDataFast(kgrid.z, kgrid.x, p, sensor_z, sensor_x);
Error in ==> ej211 at 71
sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor, input_args{:});
```

And I don´t have any idea of where the error is. I think it is interesting because GPU handles it and I just expected eons in the CPU simulation time, but not a crash.

Thank you in advance.

Daniel.