Mercurial > jwe > octave
view liboctave/array/dim-vector.cc @ 29949:029880dbbebb
prefer xelem over indexing m_rep in dim_vector class
If handle low-dimensional dim_vector objects with special case code,
it will help to have fewer direct references to the arrays of
dimensions.
* dim-vector.h, dim-vector.cc: Use xelem methods to refer to elements
of the dimension array m_rep.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Thu, 05 Aug 2021 11:43:32 -0400 |
parents | 513c4fd440b1 |
children | 13e9e244284e |
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//////////////////////////////////////////////////////////////////////// // // Copyright (C) 2003-2021 The Octave Project Developers // // See the file COPYRIGHT.md in the top-level directory of this // or <https://octave.org/copyright/>. // // Copyirght (C) 2009, 2010 VZLU Prague // // 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 // <https://www.gnu.org/licenses/>. // //////////////////////////////////////////////////////////////////////// #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include <limits> #include <new> #include <sstream> #include "Array.h" #include "dim-vector.h" // The maximum allowed value for a dimension extent. This will normally be a // tiny bit off the maximum value of octave_idx_type. // Currently 1 is subtracted to allow safe conversion of any 2D Array into // Sparse, but this offset may change in the future. octave_idx_type dim_vector::dim_max (void) { return std::numeric_limits<octave_idx_type>::max () - 1; } void dim_vector::chop_all_singletons (void) { int j = 0; int nd = ndims (); for (int i = 0; i < nd; i++) { if (xelem(i) != 1) xelem(j++) = xelem(i); } if (j == 1) xelem(1) = 1; m_ndims = (j > 2 ? j : 2); } std::string dim_vector::str (char sep) const { std::ostringstream buf; for (int i = 0; i < ndims (); i++) { buf << xelem (i); if (i < ndims () - 1) buf << sep; } std::string retval = buf.str (); return retval; } int dim_vector::num_ones (void) const { int retval = 0; for (int i = 0; i < ndims (); i++) if (xelem (i) == 1) retval++; return retval; } octave_idx_type dim_vector::safe_numel (void) const { octave_idx_type idx_max = dim_max (); octave_idx_type n = 1; int n_dims = ndims (); for (int i = 0; i < n_dims; i++) { n *= xelem(i); if (xelem(i) != 0) idx_max /= xelem(i); if (idx_max <= 0) throw std::bad_alloc (); } return n; } dim_vector dim_vector::squeeze (void) const { dim_vector new_dims = *this; new_dims.chop_all_singletons (); // preserve orientation if there is only one non-singleton dimension left if (new_dims.ndims () == 2 && xelem(0) == 1 && new_dims.elem(1) == 1) return new_dims.as_row (); return new_dims; } // This is the rule for cat(). cat (dim, A, B) works if one // of the following holds, in this order: // // 1. size (A, k) == size (B, k) for all k != dim. // In this case, size (C, dim) = size (A, dim) + size (B, dim) and // other sizes remain intact. // // 2. A is 0x0, in which case B is the result // 3. B is 0x0, in which case A is the result bool dim_vector::concat (const dim_vector& dvb, int dim) { int orig_nd = ndims (); int ndb = dvb.ndims (); int new_nd = (dim < ndb ? ndb : dim + 1); if (new_nd > orig_nd) resize (new_nd, 1); else new_nd = orig_nd; bool match = true; for (int i = 0; i < ndb; i++) { if (i != dim && xelem(i) != dvb(i)) { match = false; break; } } for (int i = ndb; i < new_nd; i++) { if (i != dim && xelem(i) != 1) { match = false; break; } } if (match) xelem(dim) += (dim < ndb ? dvb(dim) : 1); else { // Dimensions don't match. The only allowed fix is to omit 0x0. if (ndb == 2 && dvb(0) == 0 && dvb(1) == 0) match = true; else if (orig_nd == 2 && xelem(0) == 0 && xelem(1) == 0) { *this = dvb; match = true; } } chop_trailing_singletons (); return match; } // Rules for horzcat/vertcat are yet looser. // two arrays A, B can be concatenated // horizontally (dim = 2) or vertically (dim = 1) if one of the // following holds, in this order: // // 1. cat (dim, A, B) works // // 2. A, B are 2D and one of them is an empty vector, in which // case the result is the other one except if both of them // are empty vectors, in which case the result is 0x0. bool dim_vector::hvcat (const dim_vector& dvb, int dim) { if (concat (dvb, dim)) return true; else if (ndims () == 2 && dvb.ndims () == 2) { bool e2dv = xelem(0) + xelem(1) == 1; bool e2dvb = dvb(0) + dvb(1) == 1; if (e2dvb) { if (e2dv) *this = dim_vector (); return true; } else if (e2dv) { *this = dvb; return true; } } return false; } dim_vector dim_vector::redim (int n) const { int n_dims = ndims (); if (n_dims == n) return *this; else if (n_dims < n) { dim_vector retval = alloc (n); std::copy_n (m_rep, n_dims, retval.m_rep); std::fill_n (retval.m_rep + n_dims, n - n_dims, 1); return retval; } else { if (n < 1) n = 1; dim_vector retval = alloc (n); std::copy_n (m_rep, n-1, retval.m_rep); // Accumulate overflow dimensions into last remaining dimension int k = xelem(n-1); for (int i = n; i < n_dims; i++) k *= xelem(i); retval.xelem(n-1) = k; // All dim_vectors are at least 2-D. Make Nx1 if necessary. if (n == 1) retval.xelem(1) = 1; return retval; } } Array<octave_idx_type> dim_vector::as_array (void) const { octave_idx_type nd = ndims (); Array<octave_idx_type> retval (dim_vector (1, nd)); for (octave_idx_type i = 0; i < nd; i++) retval(i) = elem (i); return retval; }