<div dir="ltr">good news/bad news: the data command seems to preserve the values of the m-variables. But for some reason, the pointer field of those variables is now null. So, while the data is still accessible from the closure, it cannot be used with gsl because the pointer information used by gsl to access it is missing.<br>
<br>I think that I am looking for the following type of functionality: we create an LU decomposition within a closure, and than can apply it for multiple solutions, inverse, determinant, etc. Here is a sample idea (untested):<br>
<br>(defun lu-closure (mat)<br> (letm ((mat* (matrix-double-float mat))<br> (dim (array-dimension mat 0))<br> (per* (permutation dim)))<br> (lu-decomp mmat* per*)<br> (lambda (command &rest args)<br> (case command<br>
(:invert (letm ((inv* (matrix-double-float dim dim)))<br> (lu-invert mmat* per* inv*)<br> (data inv*)))<br> (:solve (letm ((rhs* (first args))<br> (x* (vector-double-float dim)))<br>
(lu-solve mmat* per* rhs* x*)<br> (data x*)))))))<br><br>(One could of course, just return and save the matrix and permutation vector, and apply them subsequently. I'm not sure which is the more lispy way)<br>
<br>Mirko<br><br><br><br><div class="gmail_quote">---------- Forwarded message ----------<br>From: <b class="gmail_sendername">Mirko Vukovic</b> <<a href="mailto:mirko.vukovic@gmail.com">mirko.vukovic@gmail.com</a>><br>
Date: Wed, Aug 6, 2008 at 11:12 AM<br>Subject: Fwd: keeping m-variables in closures<br>To: <a href="mailto:gsll-devel@common-lisp.net">gsll-devel@common-lisp.net</a><br><br><br><div dir="ltr">Actually something else may be going on here, because the m-variable x
can be accessed later on. I thought that maybe calls to lu-solve may
obliterate mmat and mrhs but that does not seem to be the case - I commented those calls out, but mmat and mrhs are still nils.<br><font color="#888888"><br>Mirko</font><div><div></div><div class="Wj3C7c"><br><br><br><div class="gmail_quote">
---------- Forwarded message ----------<br>
From: <b class="gmail_sendername">Mirko Vukovic</b> <<a href="mailto:mirko.vukovic@gmail.com" target="_blank">mirko.vukovic@gmail.com</a>><br>Date: Wed, Aug 6, 2008 at 11:01 AM<br>Subject: keeping m-variables in closures<br>
To: <a href="mailto:gsll-devel@common-lisp.net" target="_blank">gsll-devel@common-lisp.net</a><br>
<br><br><div dir="ltr">Hello folks<br><br>(the following is not a showstopper, but I am just curious).<br><br>I am trying to define a closure (still doing LU decompositions and matrix solutions), and would like to keep some of the variables around for further processing. Here is one example<br>
<br>(defun parallel-plate-equilibrium (eps0 T0 eps1- eps1+ eps2 T2<br> &key (q1 0d0))<br> (letm ((dim 5)<br> (mat (make-array (list dim dim)<br> :element-type 'double-float<br>
:initial-contents<br> (list (list 1d0 (1- eps0) 0d0 0d0 0d0)<br> (list (1- eps1-) 1d0 0d0 0d0 (0- eps1-))<br> (list 0d0 0d0 1d0 (1- eps1+) (0- eps1+))<br> (list 0d0 0d0 (1- eps2) 1d0 0d0)<br>
(list (0- eps1-) 0d0 0d0 (0- eps1+) (+ eps1- eps1+)))))<br> (mmat (matrix-double-float mat))<br>;; (mmat0 mmat)<br> (rhs (make-array dim<br> :element-type 'double-float<br> :initial-contents (list (st4 T0 eps0) 0d0 0d0<br>
(st4 T2 eps2) q1)))<br> (mrhs (vector-double-float rhs))<br> (per (permutation dim))<br> (res (vector-double-float dim))<br> (0-vec (vector-double-float (make-array dim<br> :initial-element 0d0)))<br>
(x (vector-double-float dim)))<br> (lu-decomp mmat per)<br> (lu-solve mmat per mrhs x)<br> (data x)<br> (lambda (command)<br> (case command<br> ;; these two will fail because mmat, mrhs, mmat0 are nil<br>
;; (:solve (lu-solve mmat per mrhs x))<br> ;; (:check (gemv :notrans 1d0 mmat0 x 0d0 0-vec))<br> (:mat mat)<br> (:rhs rhs)<br> (:temp (expt (/ (aref (data x) 4)<br> +sigma+)<br> 0.25))<br>
(:fluxes (data x))))))<br><br><br>However, it seems that gsll's variables are discarded once the letm form is done (as per documentation, and also with macroexpansion). But the code for letm mentions some "freers", which gave me hope that I can specify the freer as NIL. But I could not figure that one out quite yet. So, is it possible to save some of gsll's variables for later use?<br>
<br>Thanks,<br><br>Mirko<br></div>
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