# HG changeset patch
# User jwe
# Date 848447706 0
# Node ID 1dca28c213f0d9cdf0ddefaec17abf505268610a
# Parent  6f71af650490f7e32738384c0b8f4e3b80790d4e
[project @ 1996-11-19 23:54:48 by jwe]

diff --git a/scripts/general/common_size.m b/scripts/general/common_size.m
new file mode 100644
--- /dev/null
+++ b/scripts/general/common_size.m
@@ -0,0 +1,70 @@
+## Copyright (C) 1995, 1996  Kurt Hornik
+## 
+## 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 2, 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 file.  If not, write to the Free Software Foundation,
+## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+## usage:  [errorcode, y_1, ...] = common_size (x_1, ...)
+##
+## Determine if all input arguments are either scalar or of common
+## size.  In this case, errorcode is zero, and y_i is a matrix of the
+## common size with all entries equal to x_i if this is a scalar or
+## x_i otherwise.
+##
+## If the inputs cannot be brought to a common size, errorcode is 1, and
+## y_i is x_i.
+##
+## For example,
+##
+##   [errorcode, a, b] = common_size ([1 2; 3 4], 5)
+##
+## returns errorcode = 0, a = [1 2, 3 4], b = [5 5; 5 5].
+##
+## This is useful for implementing functions where arguments can either
+## be scalars or of common size.
+
+## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
+## Created: 15 October 1994
+## Adapted-By: jwe
+
+function [errorcode, ...] = common_size (...)
+  
+  if (nargin < 2)
+    error ("common_size: only makes sense if nargin >= 2");
+  endif
+
+  va_start ();
+  for k = 1 : nargin
+    s(k, :) = size (va_arg ());
+  endfor
+  
+  m = max (s);
+  if (any (any ((s != 1)') & any ((s != ones (nargin, 1) * m)')))
+    errorcode = 1;
+    va_start ();
+    for k = 1 : nargin
+      vr_val (va_arg ());
+    endfor
+  else
+    errorcode = 0;
+    va_start ();
+    for k = 1 : nargin
+      if (prod (s(k, :)) == 1)
+	vr_val (va_arg () * ones (m));
+      else
+	vr_val (va_arg ());
+      endif
+    endfor
+  endif
+
+endfunction
diff --git a/scripts/general/diff.m b/scripts/general/diff.m
new file mode 100644
--- /dev/null
+++ b/scripts/general/diff.m
@@ -0,0 +1,68 @@
+## Copyright (C) 1995, 1996  Kurt Hornik
+## 
+## 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 2, 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 file.  If not, write to the Free Software Foundation,
+## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+## usage:  diff (x [, k])
+##
+## If x is a vector of length n, diff (x) is the vector of first
+## differences x(2) - x(1), ..., x(n) - x(n-1).
+##
+## If x is a matrix, diff (x) is the matrix of column differences.
+## diff (x, k), where k is a nonnegative integer, returns the k-th
+## differences.
+
+## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
+## Created: 2 February 1995
+## Adapted-By: jwe
+
+function x = diff (x, k)
+  
+  if (nargin == 1)
+    k = 1;
+  elseif (nargin == 2)
+    if (! (is_scalar (k) && k == round (k) && k >= 0))
+      error ("diff: k must be a nonnegative integer");
+    elseif (k == 0)
+      return;
+    endif
+  else
+    usage ("diff (x [, k]");
+  endif
+  
+  if (isstr (x))
+    error ("diff: symbolic differentiation not (yet) supported");
+  elseif (is_vector (x))
+    n = length (x);
+    if (n <= k)
+      x = [];
+    else
+      for i = 1 : k
+	x = x (2 : (n - i + 1)) - x (1 : (n - i));
+      endfor
+    endif
+  elseif (is_matrix (x))
+    n = rows (x);
+    if (n <= k)
+      x = [];
+    else
+      for i = 1 : k
+	x = x (2 : (n - i + 1), :) - x (1: (n - i), :);
+      endfor
+    endif
+  else
+    x = [];
+  endif
+
+endfunction
diff --git a/scripts/general/nextpow2.m b/scripts/general/nextpow2.m
new file mode 100644
--- /dev/null
+++ b/scripts/general/nextpow2.m
@@ -0,0 +1,45 @@
+## Copyright (C) 1995, 1996 Kurt Hornik
+## 
+## 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 2, 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 file.  If not, write to the Free Software Foundation,
+## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+## usage:  nextpow2 (x)
+##
+## If x is a scalar, returns the first integer n such that
+## 2^n >= abs (x). 
+##
+## If x is a vector, return nextpow2 (length (x)). 
+
+## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
+## Created: 7 October 1994
+## Adapted-By: jwe
+
+function n = nextpow2 (x)
+  
+  if (nargin != 1)
+    usage ("nextpow2 (x)");
+  endif
+
+  if (is_vector (x))
+    x = length (x);
+  elseif (! is_scalar (x))
+    error ("nextpow2: x must be a scalar or a vector");
+  endif
+  
+  [f, n] = log2 (abs (x));
+  if (f == 0.5)
+    n = n - 1;
+  endif
+  
+endfunction
diff --git a/scripts/general/shift.m b/scripts/general/shift.m
new file mode 100644
--- /dev/null
+++ b/scripts/general/shift.m
@@ -0,0 +1,60 @@
+## Copyright (C) 1995, 1996  Kurt Hornik
+## 
+## 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 2, 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 file.  If not, write to the Free Software Foundation,
+## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+## usage: y = shift (x, b)
+##
+## If x is a vector, perform a circular shift of length b of the
+## elements of x.
+##
+## If x is a matrix, do the same for each column of x.
+
+## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
+## Created: 14 September 1994
+## Adapted-By: jwe
+
+function y = shift (x, b)
+  
+  if (nargin != 2)
+    error ("usage: shift (X, b)");
+  endif
+
+  [nr nc] = size (x);
+  
+  if (nr == 0 || nc == 0)
+    error ("shift: x must not be empty");
+  elseif (nr == 1)
+    x = x.';
+    nr = nc;
+    nc = 0;
+  endif
+
+  if (! (is_scalar (b) && b == round (b)))
+    error ("shift: b must be an integer");
+  endif
+
+  if (b >= 0)
+    b = rem (b, nr);
+    y = [x (nr - b + 1 : nr, :); x (1 : nr - b, :)];
+  elseif (b < 0)
+    b = rem (abs (b), nr);
+    y = [x (b + 1 : nr, :); x (1 : b, :)];
+  endif
+
+  if (nc == 0)
+    y = reshape (y, 1, nr);
+  endif
+
+endfunction
diff --git a/scripts/signal/detrend.m b/scripts/signal/detrend.m
new file mode 100644
--- /dev/null
+++ b/scripts/signal/detrend.m
@@ -0,0 +1,56 @@
+## Copyright (C) 1995, 1996  Kurt Hornik
+## 
+## 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 2, 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 file.  If not, write to the Free Software Foundation,
+## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+## usage:  detrend (x [, p])
+##
+## If x is a vector, detrend (x, p) removes the best fit of a
+## polynomial of order p from the data x.
+##
+## If x is a matrix, detrend (x, p) does the same for each column.
+##
+## If p is not specified, p = 1 is used, i.e., a linear trend is
+## removed.
+
+## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
+## Created: 11 October 1994
+## Adapted-By: jwe
+  
+function y = detrend (x, p)
+  
+  if (nargin == 1)
+    p = 1;
+  elseif (nargin == 2)
+    if (! (is_scalar (p) && p == round (p) && p >= 0))
+      error ("detrend:  p must be a nonnegative integer");
+    endif
+  else
+    usage ("detrend (x [, p])");
+  endif
+  
+  [m, n] = size (x);
+  if (m == 1)
+    x = x';
+  endif
+  
+  r = rows (x);
+  b = ((1 : r)' * ones (1, p + 1)) .^ (ones (r, 1) * (0 : p));
+  y = x - b * (b \ x);
+  
+  if (m == 1)
+    y = y';
+  endif
+  
+endfunction