<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">It may also be relevant to know what hydro reconstruction method is being used in the case of USM (for both Sean and Jonathan?). There are known problems of this sort when using HLLD, for example. <br class="">
<br class=""><div><blockquote type="cite" class=""><div class="">On May 11, 2016, at 8:56 AM, Sean Couch <<a href="mailto:smc@flash.uchicago.edu" class="">smc@flash.uchicago.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Jonathan,<div class=""><br class=""></div><div class="">I’ve seen similar, though not identical, artifacts at refinement boundaries with USM using similar nested AMR grids in the context of stellar core collapse. I was also able to reproduce artifacts using a simple field loop advection test that traverses a fixed jump in refinement. What I found helped or, in the latter case, completely cleared it up was the following settings:</div><div class=""><br class=""></div><div class="">E_modification = .true. # High order algorithm for E-field construction <br class="">E_upwind = .true. # upwinding for E-field construction <br class="">energyFix = .true. # Update magnetic energy using staggered B-fields</div><div class="">prolMethod = “injection_prol" # Prolongation method (injecton_prol, balsara_prol) </div><div class=""><br class=""></div><div class="">I think the last setting in particular is relevant here. This is the method of prolongation in the guardcells at refinement boundaries. What option are you currently using? Injection is the default. You may try switching the prolMethod and see if that changes anything. </div><div class=""><br class=""></div><div class="">I’m interested to here if any of this as an effect on what you’re seeing!</div><div class=""><br class=""></div><div class="">Sean</div><div class=""><br class=""><div class="">
<div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class="">----------------------------------------------------------------------------------------------------------<br class="">Sean M. Couch</div><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Assistant Professor<br class="">Department of Physics and Astronomy<br class="">Department of Computational Mathematics, Science, and Engineering<br class="">National Superconducting Cyclotron Laboratory/Facility for Rare Isotope Beams<br class="">Michigan State University<br class="">567 Wilson Rd, 3250 BPS<br class="">East Lansing, MI 48824<br class="">(517) 884-5035 —— <a href="mailto:couch@pa.msu.edu" class="">couch@pa.msu.edu</a> —— <a href="http://www.pa.msu.edu/~couch" class="">www.pa.msu.edu/~couch</a></div><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class=""><br class=""><br class=""><br class=""></div></div></div></div></div></div></div>
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<br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 11, 2016, at 7:55 AM, Jonathan Thurgood <<a href="mailto:jonathan.thurgood@northumbria.ac.uk" class="">jonathan.thurgood@northumbria.ac.uk</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Dear All,<span class="Apple-converted-space"> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">I was hoping someone might be able help me to overcome a seemingly serious problem which looks like it might prohibit me from migrating my current research project to FLASH.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><u class="">SETUP DESCRIPTION:<o:p class=""></o:p></u></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">The test setup is a linear, 2D magnetic null point:<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class="">B=[x,-y] .<span class="Apple-converted-space"> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">This is a cylindrically symmetric structure where the magnetic field strength linearly increases with radius. It is in force balance between magnetic tension and magnetic pressure and is known to be a stable equilibrium. All other parameters are taken as constants. I essentially want to study implosions guided into this structure, so have implemented a ‘fixed’ multi-resolution mesh whereby the highest levels of refinement are clustered towards B=0 at the origin, e.g.:<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/fig_fieldlines.png" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/fig_fieldlines.png</a> (2d null point, field line structure)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/nullpoint_modb.png" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/nullpoint_modb.png</a><span class="Apple-converted-space"> </span> (2d null point, modB profile and multi-resolution grid overlaid)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/grid_structure.png" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/grid_structure.png</a><span class="Apple-converted-space"> </span>(grid structure)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">I have implemented this by adding the following lines to Grid_markRefineDerefine.F90, after line 131 but before line 135 (without any other modification).<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt 36pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">! call Grid_markRefineSpecialized<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt 36pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""> gmrs_size = 4<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt 36pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""> gmrs_spec = (/ 0.0, 0.0, 0.0, 0.01 /)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt 36pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""> call Grid_markRefineSpecialized(INRADIUS, gmrs_size, gmrs_spec, lrefine_max)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">I have turned off adaptive refinement by not specifying any refine_vars in flash.par . This is because I am worried about prolongation of a B=0 containing cell causing issues, so would prefer to set the equilibrium field directly in the initial condition to ensure only one cell contains the null point itself. <i class="">Please note also that I am worried that it is possible that the problem I am about to describe will be manifest in many other setups / applications with actual adaptive refinement also, but would be harder to spot.</i><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><u class="">PROBLEM DESCRIPTION / FIGURES:<o:p class=""></o:p></u></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">If I then run the code to test the stability of the equilibrium (ie., no perturbations), the following current pattern quickly builds up at the boundaries of each refinement level. This then launches inward-propagating waves towards the origin/null point, at large enough amplitudes to interfere with the solution.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order2.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order2.gif</a><span class="Apple-converted-space"> </span>(CurZ, USM, monotonic, interpolation order 2)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">I believe this problem is to do with the guard cell filling by interpolation on the refinement boundary calculating an inappropriate field value which specifies a bogus current and launches waves driven by this erroneous imbalance of Lorentz force. This seems to be particularly bad in the corners here where the field strength is increasing obliquely to the cell faces, and so we have the impression of wave fronts emanating predominantly from the corners of the refinement boundaries.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Changing the monotonic interpolation order for guard cell filling, or switching to 8 wave with PARAMESH’s native interpolation, unfortunately does not fix this, but does change the shape and size of the artefacts as follows<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order0.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order0.gif</a><span class="Apple-converted-space"> </span>(curz, USM, monotonic, interpolation order 0)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order1.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order1.gif</a><span class="Apple-converted-space"> </span>(curz, USM, monotonic, interpolation order 1)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order2.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_usm_monotonic_order2.gif</a><span class="Apple-converted-space"> </span>(curz, USM, monotonic, interpolation order 2)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_8wave_native.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_8wave_native.gif</a><span class="Apple-converted-space"> </span> (curz, 8wave,native)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">It is also interesting to note that I have in the past encountered a similar qualitative current build up / wave launching from the external/physical boundary if I use, say, outflow boundary conditions (or any other default) at the null, rather than my user defined condition which explicitly sets the field in the boundary.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_uniformgrid_defaultbc.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_uniformgrid_defaultbc.gif</a><span class="Apple-converted-space"> </span> (curz, USM, outflow boundary + uniform)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/current_uniformgrid_userbc.gif" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/current_uniformgrid_userbc.gif</a> (curz, USM, user defined boundary + uniform grid)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class="">(note, by uniform grid I mean that these runs just set minimum and maximum refinement level to be the same, rather than switching to UG mode properly)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">You can see that any current for the correct BC is just numerical noise (note the magnitude), whereas the default boundary conditions give similar behaviour to that noticed at the refinement boundaries. I think this supports the idea that field is not correctly calculated at the boundaries of refinement (in the case of using outflow boundary at a null, field is incorrectly specified by the BC, in the case of refinement region boundaries, field is incorrectly specified by interpolation.)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><u class="">OTHER SETUPS THAT SEEM TO HAVE THE SAME PROBELM<o:p class=""></o:p></u></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">I can also reproduce the problem in another geometry suggesting that it isn’t specific or unique my 2D null point.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">For example, I’ve tried the one dimensional field used in the Taylor problem and other reconnection studies. Here, if<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class="">B = [0,x] + pressure chosen to maintain force balance<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/taylor_problem_modb.png" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/taylor_problem_modb.png</a><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""> (see also<span class="Apple-converted-space"> </span><a href="http://adsabs.harvard.edu/abs/2003PhPl...10.4284F" style="color: purple; text-decoration: underline;" class="">http://adsabs.harvard.edu/abs/2003PhPl...10.4284F</a><span class="Apple-converted-space"> </span>, which considered this problem with an early version of FLASH)<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">is considered with the same sort of static, multi-level grid I used at the null no such problems are initially encountered.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">However, if one rotates everything by 45degrees so that the gradients in magnetic field are now oblique to the Cartesian grid, e.g.,<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; text-indent: 36pt;" class=""><a href="https://jonathanthurgood.files.wordpress.com/2016/05/taylor_problem_rotated_modb.png" style="color: purple; text-decoration: underline;" class="">https://jonathanthurgood.files.wordpress.com/2016/05/taylor_problem_rotated_modb.png</a><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">similar artefacts to those described above for the null point can be clearly seen at the refinement boundaries.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Although I think I have the gist of why this is happening, I’m not sure about how to narrow it down further or begin to correct it. Any advice on any aspect of the above, how to narrow this down further, possible solutions or general advice would be very much appreciated – I am very stuck!<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Thanks for reading.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Best regards,<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;" class="">Jonathan</div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></body></html>