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diff --git a/journal/19jan2009.html b/journal/19jan2009.html new file mode 100644 index 0000000..270f527 --- /dev/null +++ b/journal/19jan2009.html @@ -0,0 +1,50 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" +"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> +<head><title>bnewbold thesis</title></head> +<body style="margin: 25px; font-family: helvetica;"> +<h1 style="border-bottom: 2px solid;"> +Journal: Jan 19, 2009</h1> +<i>Bryan Newbold, <a href="mailto:bnewbold@mit.edu">bnewbold@mit.edu</a></i><br /> +<i><a href="http://web.mit.edu/bnewbold/thesis/"> +http://web.mit.edu/bnewbold/thesis/</a></i> +<br /><br /> +<!-- ================================================================ --> +<!-- ================================================================ --> + +Finished the Seasoned Schemer yesturday. I've been looking through R5RS, it's +great how short it is! (50 pages) + +From the scmutils manual: +<blockquote> +Some structures, such as the ones that represent inertia tensors, must +be inverted. (The "m" above may be an inertia tensor!) Division is +arranged to make this work, when possible. The details are too hairy +to explain in this short document. We probably need to write a book +about this! +</blockquote> +Indeed! +<br /><br /> +I also liked this quote from Sean Carrol's Spacetime and Geometry (p485): +<blockquote> +The nice property of tensors, that there is usually only one sensible thing to do based on index placement, is of great help here." +</blockquote> +Sounds like a call for computation? +<hr /> +I've been working on a sage/scheme interface a bit. The problem i'm running +into now is disabling the interrupt REPL in MIT/GNU Scheme; I just want it to +leave an error string and drop back to the base REPL. I could edit the pexpect +routines in sage to try and catch all the pretinent interrupt strings, but +I think it would be better to just have the error interrupt hook in scheme +do the simple thing. +<br /> +For now, i'm actually going to switch over to the "scm" scheme distribution +which is much simpler and get that going well with sage, then try MIT/GNU +scheme again. +<br /><br /> +<a href="16jan2009.html"><i>(previous entry</i></a> + +<!-- ================================================================ --> +<!-- ================================================================ --> +</body> +</html> |