Mercurial > octave
view libinterp/corefcn/pow2.cc @ 33577:2506c2d30b32 bytecode-interpreter tip
maint: Merge default to bytecode-interpreter
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Sat, 11 May 2024 18:49:01 -0400 |
parents | 2e484f9f1f18 |
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//////////////////////////////////////////////////////////////////////// // // Copyright (C) 2022-2024 The Octave Project Developers // // See the file COPYRIGHT.md in the top-level directory of this // distribution or <https://octave.org/copyright/>. // // 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 <cmath> #include "lo-array-errwarn.h" #include "defun.h" #include "error.h" #include "errwarn.h" // FIXME: According to cppreference.com the implementation of `ldexp (f, e)` // might be less efficient that the corresponding `f * exp2 (e)`. Consider // replacing our implementation with the latter. template <typename T> void map_2_xldexp (Array<T>& y, const Array<T>& f, const Array<T>& e) { if (f.numel () == e.numel () || e.numel () == 1) y = Array<T> (f.dims ()); else if (f.numel () == 1) y = Array<T> (e.dims ()); else octave::err_nonconformant ("pow2", f.dims (), e.dims ()); octave_idx_type f_inc = (f.numel () == 1) ? 0 : 1; octave_idx_type e_inc = (e.numel () == 1) ? 0 : 1; for (octave_idx_type i = 0; i < y.numel (); i++) y.xelem (i) = std::ldexp (f.xelem (i * f_inc), static_cast<int> (e.xelem (i * e_inc))); } void map_2_xldexp_sparse (SparseMatrix& y, const SparseMatrix& f, const SparseMatrix& e) { if (e.numel () == 1) { int ee = static_cast<int> (e.data (0)); for (octave_idx_type i = 0; i < y.nnz (); i++) y.data (i) = std::ldexp (f.data (i), ee); } else if (f.numel () == e.numel ()) { octave_idx_type col = 1; for (octave_idx_type i = 0; i < y.nnz (); i++) { // Determine current column. while (i >= f.cidx (col)) col++; int ee = static_cast<int> (e.xelem (f.ridx (i), col - 1)); y.data (i) = std::ldexp (f.data (i), ee); } } else octave::err_nonconformant ("pow2", f.dims (), e.dims ()); } OCTAVE_BEGIN_NAMESPACE(octave) DEFUN (pow2, args, , doc: /* -*- texinfo -*- @deftypefn {} {@var{y} =} pow2 (@var{x}) @deftypefnx {} {@var{y} =} pow2 (@var{f}, @var{e}) With one input argument, compute @tex $y = 2^x$ @end tex @ifnottex y = 2 .^ x @end ifnottex for each element of @var{x}. With two input arguments, return @tex $y = f \cdot 2^e$, @end tex @ifnottex y = f .* (2 .^ e). @end ifnottex where for complex inputs only the real part of both inputs is regarded and from @var{e} only the real integer part. This calling form corresponds to C/C++ standard function @code{ldexp()}. @seealso{log2, nextpow2, power} @end deftypefn */) { if (args.length () < 1 || args.length () > 2) print_usage (); if (! args(0).isfloat ()) err_wrong_type_arg ("pow2", args(0)); // Call exp2(f) where possible for numerical more accurate results. if (args.length () == 1) { if (args(0).iscomplex ()) { // The C++ standard does not define exp2 for complex arguments. // Therefore call `2.^x`. octave_value retval = octave::binary_op (octave_value::op_el_pow, 2, args(0)); // Preserve sparse datatype, but even for sparse input fill-up // is unavoidable `2^0 == 1` thus cast only. if (args(0).issparse ()) retval = octave_value (retval.sparse_complex_matrix_value ()); return ovl (retval); } else if (args(0).is_single_type ()) { FloatNDArray x = args(0).float_array_value (); FloatNDArray y (x.dims ()); for (octave_idx_type i = 0; i < y.numel (); i++) y.xelem (i) = std::exp2 (x.xelem (i)); return ovl (y); } else { NDArray x = args(0).array_value (); NDArray y (x.dims ()); for (octave_idx_type i = 0; i < y.numel (); i++) y.xelem (i) = std::exp2 (x.xelem (i)); // Preserve sparse datatype, but even for sparse input fill-up // is unavoidable `2^0 == 1` thus cast only. if (args(0).issparse ()) return ovl (SparseMatrix (y)); else return ovl (y); } } // For Matlab compatibility, the two argument call `y = pow2 (f, e)` // corresponds to std::ldexp() (see bug #61968). The resulting y is // computed quickly by adding the integer part of e to the floating-point // exponent of f. if (! args(1).isfloat ()) err_wrong_type_arg ("pow2", args(1)); if (args(0).iscomplex () || args(1).iscomplex ()) warning_with_id ("Octave:pow2:imaginary-ignored", "pow2: imaginary part is ignored"); // Note: Matlab R2021a errors on `pow2 (sparse (f), single (e))`, // but sparsity in f determines output and can significantly // reduce computation, e.g. `N=1e5; pow2(speye(N),sparse(N,N))`. if (args(0).issparse ()) { SparseMatrix f = args(0).sparse_matrix_value (); // Special case: return a sparse zero matrix in size of e. if ((f.numel () == 1) && (f.nnz () == 0)) return ovl (SparseMatrix (args(1).rows (), args(1).columns ())); // Only do sparse computation, if it pays off. For scalar f fill-up // is unavoidable even for sparse e because `f * 2^0 == f`. Use dense // code below in this case. if (f.numel () > 1) { SparseMatrix e = args(1).sparse_matrix_value (); SparseMatrix y = SparseMatrix (f); map_2_xldexp_sparse (y, f, e); return ovl (y); } } if (args(0).is_single_type () || args(1).is_single_type ()) { FloatNDArray f = args(0).float_array_value (); FloatNDArray e = args(1).float_array_value (); FloatNDArray y; map_2_xldexp (y, f, e); return ovl (y); } else { NDArray f = args(0).array_value (); NDArray e = args(1).array_value (); NDArray y; map_2_xldexp (y, f, e); // Preserve sparse datatype. // Cases for efficient use of sparsity were treated above already. if (args(0).issparse ()) return ovl (SparseMatrix (y)); else return ovl (y); } } /* ## Call `y = pow2 (x)` %!test %! fcns = {@double, @single, @complex}; %! x = [3, 0, -3]; %! v = [8, 1, .125]; %! for i = 1:numel (fcns) %! fcn = fcns{i}; %! assert (pow2 (fcn (x)), fcn (v), sqrt (eps)); %! endfor %!test %! fcns = {@double, @single, @complex, @sparse}; %! x = [3, 1, -3]; %! v = [8, 2, .125]; %! for i = 1:numel (fcns) %! fcn = fcns{i}; %! assert (pow2 (fcn (x)), fcn (v), sqrt (eps)); %! endfor %!test %! fcns = {@double, @single, @complex, @sparse}; %! x = [1, 1+1i, 1i]; %! for i = 1:numel (fcns) %! fcn = fcns{i}; %! assert (pow2 (fcn (x)), fcn (2) .^ fcn (x), sqrt (eps)); %! endfor ## Call `y = pow2 (f, e)` %!test %! fcns = {@double, @single, @complex, @sparse}; %! f = [2 2]; %! e = [2 2]; %! z = [8 8]; %! warning ("off", "Octave:pow2:imaginary-ignored", "local"); %! for i = 1:numel (fcns) %! fcn = fcns{i}; %! assert (pow2 (fcn (f), fcn (e)), real (fcn (z))); %! endfor ## Only integer part is taken into account. %!test %! f = 2; %! e = [2, 2.1, 2.2, 2.4, 2.5, 2.8]; %! z = 8 .* ones (1, length (e)); %! assert (pow2 (f, e), z); ## Only real part is taken into account. %!test %! f = [1+1i, 1]; %! e = 2; %! z = [4, 4]; %! warning ("off", "Octave:pow2:imaginary-ignored", "local"); %! assert (pow2 (f, e), z); %!test %! f = 1; %! e = [1+1i, 1]; %! z = [2, 2]; %! warning ("off", "Octave:pow2:imaginary-ignored", "local"); %! assert (pow2 (f, e), z); %!test %! f = [1/2, pi/4, -3/4, 1/2, 1-eps()/2, 1/2]; %! e = [1, 2, 2, -51, 1024, -1021]; %! z = [1, pi, -3, eps(), realmax(), realmin()]; %! assert (pow2 (f, e), z); ## Tests for sparsity. %!assert (pow2 (sparse (0), ones (3)), sparse (3, 3)); %!assert (pow2 (sparse (1), ones (3)), 2 .* sparse (ones (3))); %!assert (pow2 (sparse (1), speye (3)), sparse (ones (3) + eye (3))); %!assert (pow2 (sparse (3, 3), ones (3)), sparse (3, 3)); %!assert (pow2 (speye (3), ones (3)), 2 .* speye (3)); %!assert (pow2 (speye (3), 1), 2 .* speye (3)); %!test %! f = speye (3); %! e = sparse (3, 3); %! e(1,1) = 1; %! e(1,3) = 1; %! z = f; %! z(1,1) = 2; %! assert (pow2 (f, e), z); ## Large sparse matrix (only few real elements). %!test %! ## FIXME: `N = 1e5` would be a better test, but `assert` fills-up somehow. %! N = 1e3; %! assert (pow2 (speye (N), sparse (N,N)), speye (N)); %! assert (pow2 (sparse (0), speye (N)), sparse(N,N)); %!error <Invalid call> pow2 () %!error <Invalid call> pow2 (1,2,3) %!error <wrong type argument> pow2 (int8 (1)) %!error <wrong type argument> pow2 (2, int8 (1)) %!warning <imaginary part is ignored> pow2 (i, 2); %!warning <imaginary part is ignored> pow2 (2, i); %!error <pow2: nonconformant arguments> pow2 ([1,2], [3,4,5]) %!error <pow2: nonconformant arguments> pow2 (sparse ([1,2]), sparse ([3,4,5])) */ OCTAVE_END_NAMESPACE(octave)