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Re: num2cell
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From: |
David Bateman |
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Subject: |
Re: num2cell |
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Date: |
Sun, 11 Sep 2005 23:52:39 +0200 |
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User-agent: |
Mozilla Thunderbird 1.0.2 (Windows/20050317) |
Søren Hauberg a écrit :
Hi,
Does anybody have an implementation of num2cell that I can have?
(it's not in octave-forge)
/Søren
Soren,
I started thinking about this a bit, and it seems to me that the only
way to do this is with a loop, and so the only way to do it efficiently
is in an oct-file... I started implementing this and have a solution
attached for NDArray and ComplexNDArray. It needs to be expanded to
allow other types of arguments (charArray, int8Array, etc, and maybe
even sparse matrices if matlab allows this). However, I personally don't
intend to do this.. Please find attached my code that I committed to
octave-forge... If you want to add the other cases, you'll probably need
to be smarter about the way the code is structured, or at least create a
macro to do all the real work if you don't want the size to explode...
Cheers
David
/*
Copyright (C) 2005 David Bateman
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 program; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
In addition to the terms of the GPL, you are permitted to link
this program with any Open Source program, as defined by the
Open Source Initiative (www.opensource.org)
*/
#include <octave/config.h>
#include <octave/oct.h>
#include <octave/Cell.h>
DEFUN_DLD (num2cell, args, ,
"-*- texinfo -*-\n\
@deftypefn {Loadable Function} address@hidden =} num2cell (@var{m})\n\
@deftypefnx {Loadable Function} address@hidden =} num2cell (@var{m}, @var{d})\n\
Convert to matrix @var{m} into a cell array. If @var{d} is defined the\n\
value @var{c} is of dimension 1 in this dimension and the elements of\n\
@var{m} are placed in slices in @var{c}.\n\
@end deftypefn\n\
@seealso{mat2cell}")
{
int nargin = args.length();
octave_value retval;
if (nargin < 1 || nargin > 2)
usage ("num2cell");
else
{
if (args(0).is_complex_type())
{
ComplexNDArray cm = args(0).complex_array_value();
dim_vector dv = cm.dims ();
Array<int> sings;
if (nargin == 2)
{
ColumnVector dsings = ColumnVector (args(1).vector_value
(false, true));
sings.resize (dsings.length());
if (!error_state)
for (int i = 0; i < dsings.length(); i++)
if (dsings(i) > dv.length() || dsings(i) < 1 ||
D_NINT(dsings(i)) != dsings(i))
{
error ("invalid dimension specified");
break;
}
else
sings(i) = NINT(dsings(i)) - 1;
}
if (! error_state)
{
Array<idx_vector> idx(dv.length());
dim_vector new_dv (dv);
// Create new dim_vector placing all singular elements at start
for (int i = 0; i < dv.length(); i++)
{
bool found = false;
for (int j = 0; j < sings.length(); j++)
if (sings(j) == i)
{
found = true;
break;
}
if (found)
{
idx(i) = idx_vector(':');
new_dv(i) = 1;
}
}
Cell ret (new_dv);
octave_idx_type nel = new_dv.numel();
octave_idx_type ntot = 1;
for (int j = 0; j < new_dv.length()-1; j++)
ntot *= new_dv(j);
for (octave_idx_type i = 0; i < nel; i++)
{
octave_idx_type n = ntot;
octave_idx_type ii = i;
for (int j = new_dv.length() - 1; j >= 0 ; j--)
{
if (! idx(j).is_colon())
idx(j) = idx_vector (ii / n + 1);
ii = ii % n;
if (j != 0)
n /= new_dv(j-1);
}
ret(i) = cm.index (idx, 0);
}
retval = ret;
}
}
else
{
NDArray m = args(0).array_value();
dim_vector dv = m.dims ();
Array<int> sings;
if (nargin == 2)
{
ColumnVector dsings = ColumnVector (args(1).vector_value
(false, true));
sings.resize (dsings.length());
if (!error_state)
for (int i = 0; i < dsings.length(); i++)
if (dsings(i) > dv.length() || dsings(i) < 1 ||
D_NINT(dsings(i)) != dsings(i))
{
error ("invalid dimension specified");
break;
}
else
sings(i) = NINT(dsings(i)) - 1;
}
if (! error_state)
{
Array<idx_vector> idx(dv.length());
dim_vector new_dv (dv);
// Create new dim_vector placing all singular elements at start
for (int i = 0; i < dv.length(); i++)
{
bool found = false;
for (int j = 0; j < sings.length(); j++)
if (sings(j) == i)
{
found = true;
break;
}
if (found)
{
idx(i) = idx_vector(':');
new_dv(i) = 1;
}
}
Cell ret (new_dv);
octave_idx_type nel = new_dv.numel();
octave_idx_type ntot = 1;
for (int j = 0; j < new_dv.length()-1; j++)
ntot *= new_dv(j);
for (octave_idx_type i = 0; i < nel; i++)
{
octave_idx_type n = ntot;
octave_idx_type ii = i;
for (int j = new_dv.length() - 1; j >= 0 ; j--)
{
if (! idx(j).is_colon())
idx(j) = idx_vector (ii / n + 1);
ii = ii % n;
if (j != 0)
n /= new_dv(j-1);
}
ret(i) = m.index (idx, 0);
}
retval = ret;
}
}
}
return retval;
}