/usr/share/octave/packages/nurbs-1.3.13/kntbrkdegreg.m is in octave-nurbs 1.3.13-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | % KNTBRKDEGREG: Construct an open knot vector by giving the sequence of
% knots, the degree and the regularity.
%
% knots = kntbrkdegreg (breaks, degree)
% knots = kntbrkdegreg (breaks, degree, regularity)
%
% INPUT:
%
% breaks: sequence of knots.
% degree: polynomial degree of the splines associated to the knot vector.
% regularity: splines regularity.
%
% OUTPUT:
%
% knots: knot vector.
%
% If REGULARITY has as many entries as BREAKS, or as the number of interior
% knots, a different regularity will be assigned to each knot. If
% REGULARITY is not present, it will be taken equal to DEGREE-1.
%
% Copyright (C) 2010 Carlo de Falco, Rafael Vazquez
%
% 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/>.
function knots = kntbrkdegreg (breaks, degree, reg)
if (iscell (breaks))
if (nargin == 2)
reg = degree - 1;
end
if (numel(breaks)~=numel(degree) || numel(breaks)~=numel(reg))
error('kntbrkdegreg: degree and regularity must have the same length as the number of knot vectors')
end
degree = num2cell (degree);
if (~iscell (reg))
reg = num2cell (reg);
end
knots = cellfun (@do_kntbrkdegreg, breaks, degree, reg, 'uniformoutput', false);
else
if (nargin == 2)
reg = degree - 1;
end
knots = do_kntbrkdegreg (breaks, degree, reg);
end
end
function knots = do_kntbrkdegreg (breaks, degree, reg)
if (numel (breaks) < 2)
error ('kntbrkdegreg: the knots sequence should contain at least two points')
end
if (numel (reg) == 1)
mults = [-1, (degree (ones (1, numel (breaks) - 2)) - reg), -1];
elseif (numel (reg) == numel (breaks))
mults = degree - reg;
elseif (numel (reg) == numel (breaks) - 2)
mults = [-1 degree-reg -1];
else
error('kntbrkdegreg: the length of mult should be equal to one or the number of knots')
end
if (any (reg < -1))
warning ('kntbrkdegreg: for some knots the regularity is lower than -1')
elseif (any (reg > degree-1))
error('kntbrkdegreg: the regularity should be lower than the degree')
end
knots = kntbrkdegmult (breaks, degree, mults);
end
%!test
%! breaks = [0 1 2 3 4];
%! degree = 3;
%! knots = kntbrkdegreg (breaks, degree);
%! assert (knots, [0 0 0 0 1 2 3 4 4 4 4])
%!test
%! breaks = [0 1 2 3 4];
%! degree = 3;
%! reg = 1;
%! knots = kntbrkdegreg (breaks, degree, reg);
%! assert (knots, [0 0 0 0 1 1 2 2 3 3 4 4 4 4])
%!test
%! breaks = [0 1 2 3 4];
%! degree = 3;
%! reg = [0 1 2];
%! knots = kntbrkdegreg (breaks, degree, reg);
%! assert (knots, [0 0 0 0 1 1 1 2 2 3 4 4 4 4])
%!test
%! breaks = {[0 1 2 3 4] [0 1 2 3]};
%! degree = [3 2];
%! reg = {[0 1 2] 0};
%! knots = kntbrkdegreg (breaks, degree, reg);
%! assert (knots, {[0 0 0 0 1 1 1 2 2 3 4 4 4 4] [0 0 0 1 1 2 2 3 3 3]})
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