Mercurial > hg > octave-nkf
view libinterp/corefcn/__lin_interpn__.cc @ 17296:3a9efb68272d ss-3-7-6
snapshot 3.7.6
* configure.ac (OCTAVE_VERSION): Bump to 3.7.6.
author | John W. Eaton <jwe@octave.org> |
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date | Tue, 20 Aug 2013 15:17:54 -0400 |
parents | 2fc554ffbc28 |
children | d63878346099 |
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/* Copyright (C) 2007-2012 Alexander Barth 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/>. */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "lo-ieee.h" #include "dNDArray.h" #include "oct-locbuf.h" #include "defun.h" #include "error.h" #include "oct-obj.h" // equivalent to isvector.m template <class T> bool isvector (const T& array) { const dim_vector dv = array.dims (); return dv.length () == 2 && (dv(0) == 1 || dv(1) == 1); } // lookup a value in a sorted table (lookup.m) template <class T> octave_idx_type lookup (const T *x, octave_idx_type n, T y) { octave_idx_type j; if (x[0] < x[n-1]) { // increasing x if (y > x[n-1] || y < x[0]) return -1; #ifdef EXHAUSTIF for (j = 0; j < n - 1; j++) { if (x[j] <= y && y <= x[j+1]) return j; } #else octave_idx_type j0 = 0; octave_idx_type j1 = n - 1; while (true) { j = (j0+j1)/2; if (y <= x[j+1]) { if (x[j] <= y) return j; j1 = j; } if (x[j] <= y) j0 = j; } #endif } else { // decreasing x // previous code with x -> -x and y -> -y if (y > x[0] || y < x[n-1]) return -1; #ifdef EXHAUSTIF for (j = 0; j < n - 1; j++) { if (x[j+1] <= y && y <= x[j]) return j; } #else octave_idx_type j0 = 0; octave_idx_type j1 = n - 1; while (true) { j = (j0+j1)/2; if (y >= x[j+1]) { if (x[j] >= y) return j; j1 = j; } if (x[j] >= y) j0 = j; } #endif } } // n-dimensional linear interpolation template <class T> void lin_interpn (int n, const octave_idx_type *size, const octave_idx_type *scale, octave_idx_type Ni, T extrapval, const T **x, const T *v, const T **y, T *vi) { bool out = false; int bit; OCTAVE_LOCAL_BUFFER (T, coef, 2*n); OCTAVE_LOCAL_BUFFER (octave_idx_type, index, n); // loop over all points for (octave_idx_type m = 0; m < Ni; m++) { // loop over all dimensions for (int i = 0; i < n; i++) { index[i] = lookup (x[i], size[i], y[i][m]); out = index[i] == -1; if (out) break; else { octave_idx_type j = index[i]; coef[2*i+1] = (y[i][m] - x[i][j])/(x[i][j+1] - x[i][j]); coef[2*i] = 1 - coef[2*i+1]; } } if (out) vi[m] = extrapval; else { vi[m] = 0; // loop over all corners of hypercube (1<<n = 2^n) for (int i = 0; i < (1 << n); i++) { T c = 1; octave_idx_type l = 0; // loop over all dimensions for (int j = 0; j < n; j++) { // test if the jth bit in i is set bit = i >> j & 1; l += scale[j] * (index[j] + bit); c *= coef[2*j+bit]; } vi[m] += c * v[l]; } } } } template <class T, class M> octave_value lin_interpn (int n, M *X, const M V, M *Y) { octave_value retval; M Vi = M (Y[0].dims ()); OCTAVE_LOCAL_BUFFER (const T *, y, n); OCTAVE_LOCAL_BUFFER (octave_idx_type, size, n); for (int i = 0; i < n; i++) { y[i] = Y[i].data (); size[i] = V.dims ()(i); } OCTAVE_LOCAL_BUFFER (const T *, x, n); OCTAVE_LOCAL_BUFFER (octave_idx_type, scale, n); const T *v = V.data (); T *vi = Vi.fortran_vec (); octave_idx_type Ni = Vi.numel (); T extrapval = octave_NA; // offset in memory of each dimension scale[0] = 1; for (int i = 1; i < n; i++) scale[i] = scale[i-1] * size[i-1]; // tests if X[0] is a vector, if yes, assume that all elements of X are // in the ndgrid format. if (! isvector (X[0])) { for (int i = 0; i < n; i++) { if (X[i].dims () != V.dims ()) { error ("interpn: incompatible size of argument number %d", i+1); return retval; } else { M tmp = M (dim_vector (size[i], 1)); for (octave_idx_type j = 0; j < size[i]; j++) tmp(j) = X[i](scale[i]*j); X[i] = tmp; } } } for (int i = 0; i < n; i++) { if (! isvector (X[i]) && X[i].numel () != size[i]) { error ("interpn: incompatible size of argument number %d", i+1); return retval; } else x[i] = X[i].data (); } lin_interpn (n, size, scale, Ni, extrapval, x, v, y, vi); retval = Vi; return retval; } // Perform @var{n}-dimensional interpolation. Each element of then // @var{n}-dimensional array @var{v} represents a value at a location // given by the parameters @var{x1}, @var{x2},...,@var{xn}. The parameters // @var{x1}, @var{x2}, @dots{}, @var{xn} are either @var{n}-dimensional // arrays of the same size as the array @var{v} in the \"ndgrid\" format // or vectors. The parameters @var{y1}, @var{y2}, @dots{}, @var{yn} are // all @var{n}-dimensional arrays of the same size and represent the // points at which the array @var{vi} is interpolated. // //This function only performs linear interpolation. DEFUN (__lin_interpn__, args, , "-*- texinfo -*-\n\ @deftypefn {Built-in Function} {@var{vi} =} __lin_interpn__ (@var{x1}, @var{x2}, @dots{}, @var{xn}, @var{v}, @var{y1}, @var{y2}, @dots{}, @var{yn})\n\ Undocumented internal function.\n\ @end deftypefn") { octave_value retval; int nargin = args.length (); if (nargin < 2 || nargin % 2 == 0) { print_usage (); return retval; } // dimension of the problem int n = (nargin-1)/2; if (args(n).is_single_type ()) { OCTAVE_LOCAL_BUFFER (FloatNDArray, X, n); OCTAVE_LOCAL_BUFFER (FloatNDArray, Y, n); const FloatNDArray V = args(n).float_array_value (); if (error_state) { print_usage (); return retval; } for (int i = 0; i < n; i++) { X[i] = args(i).float_array_value (); Y[i] = args(n+i+1).float_array_value (); if (error_state) { print_usage (); return retval; } if (Y[0].dims () != Y[i].dims ()) { error ("interpn: incompatible size of argument number %d", n+i+2); return retval; } } retval = lin_interpn<float, FloatNDArray> (n, X, V, Y); } else { OCTAVE_LOCAL_BUFFER (NDArray, X, n); OCTAVE_LOCAL_BUFFER (NDArray, Y, n); const NDArray V = args(n).array_value (); if (error_state) { print_usage (); return retval; } for (int i = 0; i < n; i++) { X[i] = args(i).array_value (); Y[i] = args(n+i+1).array_value (); if (error_state) { print_usage (); return retval; } if (Y[0].dims () != Y[i].dims ()) { error ("interpn: incompatible size of argument number %d", n+i+2); return retval; } } retval = lin_interpn<double, NDArray> (n, X, V, Y); } return retval; } /* ## No test needed for internal helper function. %!assert (1) */