feat(stdlib): perspective constancy function (#288)

Consensys · Nov 3, 2024 · 2a9a1d1 · 2a9a1d1
1 parent 4f3723a
commit 2a9a1d1
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/src/stdlib.lisp b/src/stdlib.lisp
@@ -91,6 +91,11 @@
   (if-not-zero ct
                (remained-constant! X)))
 
+;; perspective constancy constraint
+(defpurefun ((perspective-constancy :@loob) PERSPECTIVE_SELECTOR X)
+            (if-not-zero (* PERSPECTIVE_SELECTOR (prev PERSPECTIVE_SELECTOR))
+                         (remained-constant! X)))
+
 ;; base-X decomposition constraints
 (defpurefun (base-X-decomposition ct base acc digits)
   (if-zero ct