<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On 6 Oct 2016, at 14:35, Roland Haas <<a href="mailto:rhaas@illinois.edu">rhaas@illinois.edu</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">Hello Ian,<br><br><blockquote type="cite">In this case, there is no final error message and abort, unlike in<br>the case of partially-read gridfunctions. Is this a deliberate<br>decision, <br></blockquote>Yes, this is deliberate to allow thorns to be activated in ongoing<br>simulations. There is a level 2 warning about the non-read in variables<br>so it should not go unnoticed (in theory at least).<br><br><blockquote type="cite">because for partially-read gridfunctions the results are<br>definitely wrong, whereas not reading variables at all might be OK?<br>In my particular case, the variables are scalar integers. What value<br>would the variables have in this case? Does Carpet initialise<br>variables to 0? I seem to see 0, but haven't checked carefully.<br></blockquote>They would be whatever Carpet or the memory allocator initialized them<br>to. CCTK_Initial does not run (normally) during checkpoint recovery. You<br>can have CCTK_Initial run *before* checkpoint recovery (with values in<br>the recoverd variables overwritten by the recovered values) by setting<br>Cactus::recovery_mode to "relaxed" (see flesh/src/param.ccl). This may<br>be what you had in mind.<br></blockquote><div><br></div><div>Aha, that's interesting. Though I guess it would probably confuse a lot of thorns, so I'm not sure how useful it in in practice. The initial data solver would run again, for example. I would have expected Carpet to initialise variables to poison, so I should be seeing poison. What I am doing now is initialising the thorn in basegrid, and checking an "initialised" Cactus variable. If this is 1, then I don't do anything. If it's anything other than 1 (poison, zero, etc) then I assume the thorn has never been initialised. This is probably not an approved, elegant solution, but I expect it will work.</div></div><br><div apple-content-edited="true">
<div style="color: rgb(0, 0, 0); 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;"><div style="color: rgb(0, 0, 0); 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;"><div style="color: rgb(0, 0, 0); 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;"><div style="color: rgb(0, 0, 0); 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;"><div>-- </div><div>Ian Hinder</div><div><a href="http://members.aei.mpg.de/ianhin">http://members.aei.mpg.de/ianhin</a></div></div></div></div></div>
</div>
<br></body></html>