update packages

[CreaPhase.git] / octave_packages / m / polynomial / polyout.m

diff --git a/octave_packages/m/polynomial/polyout.m b/octave_packages/m/polynomial/polyout.m
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+## Copyright (C) 1995-2012 Auburn University.  All rights reserved.
+##
+## This file is part of Octave.
+##
+## Octave 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.
+##
+## Octave 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 Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} polyout (@var{c})
+## @deftypefnx {Function File} {} polyout (@var{c}, @var{x})
+## @deftypefnx {Function File} {@var{str} =} polyout (@dots{})
+## Write formatted polynomial
+## @tex
+## $$ c(x) = c_1 x^n + \ldots + c_n x + c_{n+1} $$
+## @end tex
+## @ifnottex
+##
+## @example
+## c(x) = c(1) * x^n + @dots{} + c(n) x + c(n+1)
+## @end example
+##
+## @end ifnottex
+## and return it as a string or write it to the screen (if @var{nargout} is
+## zero).  @var{x} defaults to the string @code{"s"}.
+## @seealso{polyreduce}
+## @end deftypefn
+
+## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu>
+## Created: May 1995
+## Nov 1998: Correctly handles complex coefficients
+
+function y = polyout (c, x)
+
+  if (nargin < 1) || (nargin > 2) || (nargout < 0) || (nargout > 1)
+    print_usage ();
+  endif
+
+  if (! isvector (c))
+    error ("polyout: first argument must be a vector");
+  endif
+
+  if (nargin == 1)
+    x = "s";
+  elseif (! ischar (x))
+    error ("polyout: second argument must be a string");
+  endif
+
+  n = length (c);
+  if(n > 0)
+    n1 = n+1;
+
+    tmp = coeff (c(1));
+    for ii = 2:n
+      if (real (c(ii)) < 0)
+        ns = " - ";
+        c(ii) = -c(ii);
+      else
+        ns = " + ";
+      endif
+
+      tmp = sprintf ("%s*%s^%d%s%s", tmp, x, n1-ii, ns, coeff (c(ii)));
+
+    endfor
+  else
+    tmp = " ";
+  endif
+
+  if(nargout == 0)
+    disp (tmp);
+  else
+    y = tmp;
+  endif
+
+endfunction
+
+function str = coeff (c)
+  if (imag (c))
+    if (real (c))
+      str = sprintf ("(%s)", num2str (c, 5));
+    else
+      str = num2str (c, 5);
+    endif
+  else
+    str = num2str (c, 5);
+  endif
+endfunction
+
+%!assert (polyout ([3 2 1]), '3*s^2 + 2*s^1 + 1')
+%!assert (polyout ([3 2 1], 'x'), '3*x^2 + 2*x^1 + 1')
+%!assert (polyout ([3 2 1], 'wxyz'), '3*wxyz^2 + 2*wxyz^1 + 1')
+%!assert (polyout ([5 4 3 2 1], '1'),'5*1^4 + 4*1^3 + 3*1^2 + 2*1^1 + 1')
+%!error polyout ([])