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December 2013

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Re: [GSLL-devel] Fixing up make-grid-data for clisp (was making copy-to working in clisp+grid: fix to element-type)
by Liam Healy 26 Dec '13

26 Dec '13

My fix (as opposed to your fix) to the problem you reported in your previous email should not exhibit this problem, see my previous email. A better summary is CLISP is not a preferred platform for anything. There is a Windows port of SBCL, and has been for quite some time. A better cross-check on portability would be CCL. Liam On Fri, Jan 4, 2013 at 11:47 AM, Mirko Vukovic <mirko.vukovic(a)gmail.com>wrote: > This is a follow up on my posted fix to copy-to. For some reason this has > triggered another > error. I do not understand how that other error is triggered. The error > and the fix are discussed > at the bottom of the email > > On Fri, Jan 4, 2013 at 10:39 AM, Mirko Vukovic <mirko.vukovic(a)gmail.com>wrote: > >> The following works in sbcl+grid: >> >> (copy-to (make-array 2 :element-type 'double-float :initial-contents >> '(1.0d0 2.0d0)) 'grid:foreign-array) >> >> But it does not work in clisp+grid. >> >> The root cause lies in the function grid/array.lisp/element-type. It >> uses `(array-element-type grid)'. >> >> But this can present a problem. Quoting hyperspec: >> >> (Because of *array* <http://26_glo_a.htm#array> *upgrading*, this *type >> specifier* <http://26_glo_t.htm#type_specifier> can in some cases denote >> a *supertype* <http://26_glo_s.htm#supertype> of the *expressed array >> element type* <http://26_glo_e.htm#expressed_array_element_type> of the >> *array*.) >> >> In CLISP, array-element-type returns `T' when passed #(1d0 2d0) >> >> It returns T even when passed a simple array: >> >> (array-element-type (make-array 2 :element-type 'double-float >> :initial-contents >> '(1.0d0 2.0d0) >> :adjustable nil >> :fill-pointer nil >> :displaced-to nil) ) >> >> The proposed fix is >> >> (defmethod element-type ((grid array)) >> (type-of (row-major-aref grid 0)) >> #+skip(array-element-type grid)) >> >> Now copy-to works in clisp as well. >> >> Mirko >> >> >> After finishing this, I recompiled afresh, and got another error that I > traced to make-grid-data and make-array > > In clisp, make-array will return an array of NIL's even if the > element-type is specified as double float. In SBCL make-array > will return an array filled with 1d0. > > I had to add some clisp specific code to make-grid-data in order for it to > initialize properly. > > First, a helper function: > (defun default-element (element-type) > "Return a default element depending on element-type > " > (let ((a-list '((double-float . 1d0) > (symbol . T)))) > (let ((match (cdr (assoc element-type a-list)))) > (assert match () > "Default element type undefined for element-type ~a" > element-type) > match))) > > And second, a bit of set-up code in make-grid-data. I broke apart the > (let* statement > to provide an explicit initial element if it has not been specified > already: > > (defmethod make-grid-data > ((type (eql 'array)) dimensions rest-spec > &key (initial-element nil initial-element-p) > (initial-contents nil initial-contents-p)) > (let ((element-type (top-spec-type rest-spec))) > #+clisp > (unless (or initial-element-p > initial-contents-p) > (setf initial-element (default-element element-type) > initial-element-p t)) > (let ((array ... UNCHANGED > > > Summary: To fix to copy-to, I modified (defmethod element-type ((grid > array)) > For some unknown reason, that triggered an error in the array > initialization routine. > To fix that, I had to add code to make-grid-data, so that it fills > double-float arrays with 0d0 > instead of NIL's > > I will continue using this code to see if there are additional problems. > > BTW, I realize that CLISP is not a preferred platform for speedy > computation, but that is what I use > on Windows, until SBCL gets officially ported to it. And in addition, it > is a nice cross-check on portability. > > Mirko > > > > _______________________________________________ > GSLL-devel mailing list > GSLL-devel(a)common-lisp.net > http://lists.common-lisp.net/cgi-bin/mailman/listinfo/gsll-devel > >

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Re: [GSLL-devel] making copy-to working in clisp+grid: fix to element-type
by Liam Healy 26 Dec '13

26 Dec '13

Your solution is not a good one, because if a general array is passed to copy-to it will cause an error if all the elements are not the same type as the first one. For example, (copy-to #(1.0d0 1)) will behave incorrectly. By the way, your example with #(1d0 2d0) fails on SBCL as well, and should fail everywhere because #( ) is making a general (T) array. It is unfortunate that CLISP apparently does not have specialized arrays, but the proper solution is to use a different function. The correct solution when copying from a general array is to explicitly specify the element-type. This capability is provided by the function #'copy (copy #(1d0 2d0) :grid-type 'grid:foreign-array :element-type 'double-float) The function #'copy-to is provided merely as a convenient shortcut to using #'copy which works in many situations. The solution to your problem is to use copy with explicit element-type instead of copy-to. After debating whether to eliminate copy-to, I have added another optional argument, element-type, that defaults to *default-element-type*, and this should fix your problem. However, it is meant only as a convenience for interactive code, it should really not be put into files relying on the default value specials which may be changed. So I have also removed its use in GSLL itself. This change is untested and made in 86671c4ef057, which is in the multiple-systems branch and will be merged into master soon. I have added antik-devel to this email because this an Antik issue and has nothing to do with GSLL. On Fri, Jan 4, 2013 at 10:39 AM, Mirko Vukovic <mirko.vukovic(a)gmail.com>wrote: > The following works in sbcl+grid: > > (copy-to (make-array 2 :element-type 'double-float :initial-contents > '(1.0d0 2.0d0)) 'grid:foreign-array) > > But it does not work in clisp+grid. > > The root cause lies in the function grid/array.lisp/element-type. It uses > `(array-element-type grid)'. > > But this can present a problem. Quoting hyperspec: > > (Because of *array* <http://26_glo_a.htm#array> *upgrading*, this *type > specifier* <http://26_glo_t.htm#type_specifier> can in some cases denote > a *supertype* <http://26_glo_s.htm#supertype> of the *expressed array > element type* <http://26_glo_e.htm#expressed_array_element_type> of the > *array*.) > > In CLISP, array-element-type returns `T' when passed #(1d0 2d0) > > It returns T even when passed a simple array: > > (array-element-type (make-array 2 :element-type 'double-float > :initial-contents > '(1.0d0 2.0d0) > :adjustable nil > :fill-pointer nil > :displaced-to nil) ) > > The proposed fix is > > (defmethod element-type ((grid array)) > (type-of (row-major-aref grid 0)) > #+skip(array-element-type grid)) > > Now copy-to works in clisp as well. > > Mirko > > > > _______________________________________________ > GSLL-devel mailing list > GSLL-devel(a)common-lisp.net > http://lists.common-lisp.net/cgi-bin/mailman/listinfo/gsll-devel > >

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