Hello Everyone
I am running into a problem where I evolve a Gaussian shell scalar field alongside the BSSN equations using the Scalar/ScalarInit/ScalarBase thorns, where the initial data is isotropic but evolves to an anisotropic solution. More specifically, along the x axis I have g_yy=g_zz and along the z axis I have g_xx=g_yy, with g_xx along the x axis equal to g_zz along the z axis, despite having isotropic initial conditions. The point is illustrated by the first image being the plot of g_xx and g_zz along their respective axes at a later time, and the rest of the diagonal metric values being shown in the second image. Additionally, T_ij shows a similar problem, where T_xx along the x axis and T_zz along the z axis are equal to eachother, but not the rest of the diagonal entries of T_ij, which are all equal. [image: gxxx.PNG][image: gxxz.PNG] I have attached the parameter file used to get these results, which is a modified version of the test parameter file found in the Scalar thorn bundle.
Thanks, Nicholas Olsen
