Why this code does Not work?

function [B, id] = nrbbasisfun (points, nrb)

% NRBBASISFUN: Basis functions for NURBS % % Calling Sequence: % % B = nrbbasisfun (u, crv) % B = nrbbasisfun ({u, v}, srf) % [B, N] = nrbbasisfun ({u, v}, srf) % [B, N] = nrbbasisfun (p, srf) % % INPUT: % % u or p(1,:,:) - parametric points along u direction % v or p(2,:,:) - parametric points along v direction % crv - NURBS curve % srf - NURBS surface % % OUTPUT: % % B - Value of the basis functions at the points % size(B)=[numel(u),(p+1)] for curves % or [numel(u)*numel(v), (p+1)*(q+1)] for surfaces % % N - Indices of the basis functions that are nonvanishing at each % point. size(N) == size(B) % % % Copyright (C) 2009 Carlo de Falco % % This program is free software: you can redistribute it and/or modify % it under the terms of the GNU General Public License as published by % the Free Software Foundation, either version 3 of the License, or % (at your option) any later version.

% This program is distributed in the hope that it will be useful, % but WITHOUT ANY WARRANTY; without even the implied warranty of % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the % GNU General Public License for more details. % % You should have received a copy of the GNU General Public License % along with this program. If not, see http://www.gnu.org/licenses/.

if (   (nargin<2) ...
    || (nargout>2) ...
    || (~isstruct(nrb)) ...
    || (iscell(points) && ~iscell(nrb.knots)) ...
    || (~iscell(points) && iscell(nrb.knots) && (size(points,1)~=2)) ...
    || (~iscell(nrb.knots) && (nargout>1)) ...
    )
  error('Incorrect input arguments in nrbbasisfun');
end

if (~iscell(nrb.knots))         %%NURBS curve

    [B, id] = nrb_crv_basisfun__ (points, nrb);

elseif size(nrb.knots,2) == 2 %%NURBS surface
  if (iscell(points))
    [v, u] = meshgrid(points{2}, points{1});
    p = [u(:), v(:)]';
  else
    p = points;
  end

    [B, id] = nrb_srf_basisfun__ (p, nrb); 

else                            %%NURBS volume
  error('The function nrbbasisfun is not yet ready for volumes')
end
end

%!demo %! U = [0 0 0 0 1 1 1 1]; %! x = [0 1/3 2/3 1] ; %! y = [0 0 0 0]; %! w = [1 1 1 1]; %! nrb = nrbmak ([x;y;y;w], U); %! u = linspace(0, 1, 30); %! B = nrbbasisfun (u, nrb); %! xplot = sum(bsxfun(@(x,y) x.*y, B, x),2); %! plot(xplot, B) %! title('Cubic Bernstein polynomials') %! hold off

Is there anyone can help me? I'm trying to do the demo above and I'm having eror message. Please help.

[Lokesh Ravindranathan]

What is the error message?

[STamer]

Undefined function 'nrbcrvbasisfun' for input arguments of type 'struct'.

Error in nrbbasisfun (line 56) [B, id] = nrbcrvbasisfun (points, nrb);

[STamer]

Line 56 ---> [B, id] = nrb_crv_basisfun__ (points, nrb);

[Jan]

Please format your code properly, when you want others to encourage to read it.

Answer 1

[Jan]

The error message means, that the function nrb_crv_basisfun__ is not found. Did you installed it and if so, has the corresponding folder been added to the path?

[STamer]

Ok. Thank you. I'm so tired.Sorry for that easy question :)