Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / nurbs-1.3.6 / private / onebasisfunder__.m

diff --git a/octave_packages/nurbs-1.3.6/private/onebasisfunder__.m b/octave_packages/nurbs-1.3.6/private/onebasisfunder__.m
new file mode 100644 (file)
index 0000000..b397d10
--- /dev/null
+++ b/octave_packages/nurbs-1.3.6/private/onebasisfunder__.m
@@ -0,0 +1,39 @@
+function [N, Nder] = onebasisfunder__ (u, p, U)
+
+%  __ONEBASISFUNDER__: Undocumented internal function
+%
+%   Copyright (C) 2012 Rafael Vazquez
+%   This software comes with ABSOLUTELY NO WARRANTY; see the file
+%   COPYING for details.  This is free software, and you are welcome
+%   to distribute it under the conditions laid out in COPYING.
+
+  N = zeros (size (u));
+  Nder = zeros (size (u));
+
+  for ii = 1:numel (u)
+    if (~ any (U <= u(ii))) || (~ any (U > u(ii)))
+      continue;
+    elseif (p == 0)
+      N(ii) = 1;
+      Nder(ii) = 0;
+      continue;
+    else
+      ln = u(ii) - U(1);
+      ld = U(end-1) - U(1);
+      if (ld ~= 0)
+        aux = onebasisfun__ (u(ii), p-1, U(1:end-1))/ ld;
+        N(ii) = N(ii) + ln * aux;
+        Nder(ii) = Nder(ii) + p * aux;
+      end
+
+      dn = U(end) - u(ii);
+      dd = U(end) - U(2);
+      if (dd ~= 0)
+        aux = onebasisfun__ (u(ii), p-1, U(2:end))/ dd;
+        N(ii) = N(ii) + dn * aux;
+        Nder(ii) = Nder(ii) - p * aux;
+      end
+    end
+  end
+  
+end