Skip to content

optimize sum-linear-expressions #21

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
neil-lindquist merged 1 commit into from
Apr 21, 2026
Merged

optimize sum-linear-expressions #21

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 6 additions & 6 deletions src/expressions.lisp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,9 @@
:linear-programming/conditions)
(:import-from :alexandria
#:if-let
#:plist-alist)
#:plist-alist
#:alist-hash-table
#:hash-table-alist)
(:export #:scale-linear-expression
#:sum-linear-expressions
#:parse-linear-expression
Expand All @@ -24,13 +26,11 @@
(declaim (inline sum-linear-expressions))
(defun sum-linear-expressions (&rest exprs)
"Takes linear expressions and reduces it into a single expression."
(let ((sum (copy-alist (first exprs))))
(let ((sum (alist-hash-table (first exprs))))
(iter (for expr in (rest exprs))
(iter (for term in expr)
(if-let (pair (assoc (car term) sum))
(incf (cdr pair) (cdr term))
(push (cons (car term) (cdr term)) sum))))
sum))
(incf (gethash (car term) sum 0) (cdr term))))
(hash-table-alist sum)))


(declaim (inline scale-linear-expression))
Expand Down
Loading