Mercurial > octave
view scripts/general/idivide.m @ 33567:9f0f7a898b73 bytecode-interpreter tip
maint: Merge default to bytecode-interpreter
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Fri, 10 May 2024 17:57:29 -0400 |
parents | 2e484f9f1f18 |
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######################################################################## ## ## Copyright (C) 2008-2024 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/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{C} =} idivide (@var{A}, @var{B}, @var{op}) ## Integer division with different rounding rules. ## ## The standard behavior of integer division such as @code{@var{A} ./ @var{B}} ## is to round the result to the nearest integer. This is not always the ## desired behavior and @code{idivide} permits integer element-by-element ## division to be performed with different treatment for the fractional ## part of the division as determined by the @var{op} flag. @var{op} is ## a string with one of the values: ## ## @table @asis ## @item @qcode{"fix"} ## Calculate @code{@var{A} ./ @var{B}} with the fractional part rounded ## towards zero. ## ## @item @qcode{"round"} ## Calculate @code{@var{A} ./ @var{B}} with the fractional part rounded ## towards the nearest integer. ## ## @item @qcode{"floor"} ## Calculate @code{@var{A} ./ @var{B}} with the fractional part rounded ## towards negative infinity. ## ## @item @qcode{"ceil"} ## Calculate @code{@var{A} ./ @var{B}} with the fractional part rounded ## towards positive infinity. ## @end table ## ## @noindent ## If @var{op} is not given it defaults to @qcode{"fix"}. ## An example demonstrating these rounding rules is ## ## @example ## @group ## idivide (int8 ([-3, 3]), int8 (4), "fix") ## @result{} 0 0 ## idivide (int8 ([-3, 3]), int8 (4), "round") ## @result{} -1 1 ## idivide (int8 ([-3, 3]), int8 (4), "floor") ## @result{} -1 0 ## idivide (int8 ([-3, 3]), int8 (4), "ceil") ## @result{} 0 1 ## @end group ## @end example ## ## @seealso{ceil, floor, fix, round, ldivide, rdivide} ## @end deftypefn function C = idivide (A, B, op) if (nargin < 2) print_usage (); endif if (nargin == 2) op = "fix"; else op = lower (op); endif if (! isinteger (A) && ! isinteger (B)) error ("idivide: at least one input (A or B) must be an integer type"); elseif (isinteger (A) && isinteger (B) && ! strcmp (class (A), class (B))) error ("idivide: integer type of A (%s) must match integer type of B (%s)", class (A), class (B)); endif C = A ./ B; if (strcmp (op, "fix")) ## The following is an optimized version of `C -= (C .* B > A) .* sign (B)`. if (isscalar (B)) if (B > 0) C -= (C * B > A); else C += (C * B > A); endif else y_sel = (B > 0); if (isscalar (A)) C(y_sel) -= (C(y_sel) .* B(y_sel) > A); y_sel = ! y_sel; C(y_sel) += (C(y_sel) .* B(y_sel) > A); else C(y_sel) -= (C(y_sel) .* B(y_sel) > A(y_sel)); y_sel = ! y_sel; C(y_sel) += (C(y_sel) .* B(y_sel) > A(y_sel)); endif endif elseif (strcmp (op, "round")) return; elseif (strcmp (op, "floor")) ## The following is an optimized version of `C -= (C .* abs (B) > sign (B) .* A)`. if (isscalar (B)) if (B > 0) C -= (C * B > A); else C -= (C * B < A); endif else y_sel = (B > 0); if (isscalar (A)) C(y_sel) -= (C(y_sel) .* B(y_sel) > A); y_sel = ! y_sel; C(y_sel) -= (C(y_sel) .* B(y_sel) < A); else C(y_sel) -= (C(y_sel) .* B(y_sel) > A(y_sel)); y_sel = ! y_sel; C(y_sel) -= (C(y_sel) .* B(y_sel) < A(y_sel)); endif endif elseif (strcmp (op, "ceil")) ## The following is an optimized version of `C += (C .* abs (B) < sign (B) .* A)`. if (isscalar (B)) if (B > 0) C += (C * B < A); else C += (C * B > A); endif else y_sel = (B > 0); if (isscalar (A)) C(y_sel) += (C(y_sel) .* B(y_sel) < A); y_sel = ! y_sel; C(y_sel) += (C(y_sel) .* B(y_sel) > A); else C(y_sel) += (C(y_sel) .* B(y_sel) < A(y_sel)); y_sel = ! y_sel; C(y_sel) += (C(y_sel) .* B(y_sel) > A(y_sel)); endif endif else error ('idivide: unrecognized rounding type "%s"', op); endif endfunction %!shared a, af, b, bf %! a = int8 (3); %! af = 3; %! b = int8 ([-4, 4]); %! bf = [-4, 4]; %!assert (idivide (a, b), int8 ([0, 0])) %!assert (idivide (a, b, "floor"), int8 ([-1, 0])) %!assert (idivide (a, b, "ceil"), int8 ([0, 1])) %!assert (idivide (a, b, "round"), int8 ([-1, 1])) %!assert (idivide (af, b), int8 ([0, 0])) %!assert (idivide (af, b, "floor"), int8 ([-1, 0])) %!assert (idivide (af, b, "ceil"), int8 ([0, 1])) %!assert (idivide (af, b, "round"), int8 ([-1, 1])) %!assert (idivide (a, bf), int8 ([0, 0])) %!assert (idivide (a, bf, "floor"), int8 ([-1, 0])) %!assert (idivide (a, bf, "ceil"), int8 ([0, 1])) %!assert (idivide (a, bf, "round"), int8 ([-1, 1])) %!shared c, d %! c = int64 (4e16); %! d = int64 ([-2e8, 2e8]); %!assert <*61319> (idivide (c, d + int64 (1)), d + int64 ([-1, -1])) %!assert <*61319> (idivide (c, d + int64 (1), "floor"), d + int64 ([-2, -1])) %!assert <*61319> (idivide (c, d + int64 (1), "ceil"), d + int64 ([-1, 0])) %!assert <*61319> (idivide (c, d + int64 (1), "round"), d + int64 ([-1, -1])) %!assert <*61319> (idivide (c + int64 (1), d), d) %!assert <*61319> (idivide (c + int64 (1), d, "floor"), d + int64 ([-1, 0])) %!assert <*61319> (idivide (c + int64 (1), d, "ceil"), d + int64 ([0, 1])) %!assert <*61319> (idivide (c + int64 (1), d, "round"), d) ## Test input validation %!error idivide (uint8 (1)) %!error idivide (uint8 (1), 2, 3) %!error <at least one input> idivide (1, 2) %!error <at least one input> idivide ({1}, 2) %!error <A \(int8\) must match.* B \(uint8\)> idivide (int8 (1), uint8 (2)) %!error <unrecognized rounding type "foo"> idivide (int8 (1), 2, "foo")