Data commit

Task/Steffensens-method/EasyLang/steffensens-method.easy

@@ -0,0 +1,57 @@
+proc deCasteljau c0 c1 c2 t . r .
+   s = 1 - t
+   c01 = s * c0 + t * c1
+   c12 = s * c1 + t * c2
+   r = s * c01 + t * c12
+.
+proc xConvexLeftPar t . r .
+   call deCasteljau 2 (-8) 2 t r
+.
+proc yConvexRightPar t . r .
+   call deCasteljau 1 2 3 t r
+.
+proc implicitEq x y . r .
+   r = 5 * x * x + y - 5
+.
+proc f t . r .
+   call xConvexLeftPar t x
+   call yConvexRightPar t y
+   call implicitEq x y r
+   r += t
+.
+proc aitken p0 . r .
+   call f p0 p1
+   call f p1 p2
+   p1m0 = p1 - p0
+   r = p0 - p1m0 * p1m0 / (p2 - 2 * p1 + p0)
+.
+proc steffAitken p0 tol maxiter . p .
+   for i to maxiter
+      call aitken p0 p
+      if abs (p - p0) < tol
+         break 2
+      .
+      p0 = p
+   .
+   p = number "nan"
+.
+for i to 11
+   numfmt 1 0
+   write "t0 = " & t0 & " : "
+   call steffAitken t0 0.00000001 1000 t
+   numfmt 3 0
+   if t <> t
+      # nan
+      print "no answer"
+   else
+      call xConvexLeftPar t x
+      call yConvexRightPar t y
+      call implicitEq x y r
+      if abs r <= 0.000001
+         print "intersection at (" & x & " " & y & ")"
+      else
+         print "spurious solution"
+      .
+   .
+   t0 += 0.1
+.