1######################################################################## 2## 3## Copyright (C) 1996-2021 The Octave Project Developers 4## 5## See the file COPYRIGHT.md in the top-level directory of this 6## distribution or <https://octave.org/copyright/>. 7## 8## This file is part of Octave. 9## 10## Octave is free software: you can redistribute it and/or modify it 11## under the terms of the GNU General Public License as published by 12## the Free Software Foundation, either version 3 of the License, or 13## (at your option) any later version. 14## 15## Octave is distributed in the hope that it will be useful, but 16## WITHOUT ANY WARRANTY; without even the implied warranty of 17## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18## GNU General Public License for more details. 19## 20## You should have received a copy of the GNU General Public License 21## along with Octave; see the file COPYING. If not, see 22## <https://www.gnu.org/licenses/>. 23## 24######################################################################## 25 26## -*- texinfo -*- 27## @deftypefn {} {} polyint (@var{p}) 28## @deftypefnx {} {} polyint (@var{p}, @var{k}) 29## Return the coefficients of the integral of the polynomial whose 30## coefficients are represented by the vector @var{p}. 31## 32## The variable @var{k} is the constant of integration, which by default is 33## set to zero. 34## @seealso{polyder, polyval} 35## @end deftypefn 36 37function retval = polyint (p, k) 38 39 if (nargin < 1 || nargin > 2) 40 print_usage (); 41 endif 42 43 if (nargin == 1) 44 k = 0; 45 elseif (! isscalar (k)) 46 error ("polyint: the constant of integration must be a scalar"); 47 endif 48 49 if (! (isvector (p) || isempty (p))) 50 error ("polyint: argument must be a vector"); 51 endif 52 53 lp = length (p); 54 55 if (lp == 0) 56 retval = []; 57 return; 58 endif 59 60 if (rows (p) > 1) 61 ## Convert to column vector 62 p = p.'; 63 endif 64 65 retval = [(p ./ [lp:-1:1]), k]; 66 67endfunction 68 69 70%!test 71%! A = [3, 2, 1]; 72%! assert (polyint (A), polyint (A,0)); 73%! assert (polyint (A), polyint (A')); 74%! assert (polyint (A), [1, 1, 1, 0]); 75%! assert (polyint (A,1), ones (1,4)); 76 77%!test 78%! A = ones (1,8); 79%! B = [length(A):-1:1]; 80%! assert (polyint (A), [1./B, 0]); 81 82%!error polyint () 83%!error polyint (ones (2,2)) 84