Mercurial > octave
view scripts/miscellaneous/list_primes.m @ 32047:e3de59065cf1
inputParser.m: Re-architect internal data structures for 60% speed improvement.
Key idea is to replace Parameter and Switch structs with name field containing
a nested struct (def, val fields) with a struct array that has fields "name",
"def", and "val". This makes it possible to eliminate for loops.
* NEWS.9.md: Announce performance improvement.
* inputParser.m: Declare "Parameter" and "Switch" properties as struct arrays.
Add new private property "last_idx" which caches the last Parameter or Switch
lookup.
* inputParser.m (addRequired): Adjust input validation to use numel() now
rather than numfields().
* inputParser.m (addOptional): Adjust input validation to use numel() now
rather than numfields().
* inputParser.m (addParameter): Change code to add new Parameter to a struct
array.
* inputParser.m (addSwitch): Change code to add new Switch to a struct
array.
* inputParser.m (parse): Adjust initialization of internal variables
ParameterNames and SwitchNames to match new data structure.
Use last_idx to simplify call to validate_arg() for Parameters.
* inputParser.m (validate_arg): Move creation of error message
to code path when error has been found---No need to do it for every
function call. Don't capture "exception" variable in try/catch as
it is no longer used.
* inputParser.m (is_argname): Cache "last_idx" if match was found.
* inputParser.m (add_missing): Replace call to setdiff() with in-place
code which can take advantage of implicit knowledge to eliminate calls
to unique and input validation. Replace for loop with cell2struct/struct2cell
combination.
author | Rik <rik@octave.org> |
---|---|
date | Fri, 21 Apr 2023 11:01:40 -0700 |
parents | 597f3ee61a48 |
children | 2e484f9f1f18 |
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######################################################################## ## ## Copyright (C) 1993-2023 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{p} =} list_primes () ## @deftypefnx {} {@var{p} =} list_primes (@var{n}) ## List the first @var{n} primes. ## ## If @var{n} is unspecified, the first 25 primes are listed. ## @seealso{primes, isprime} ## @end deftypefn function p = list_primes (n = 25) if (! isreal (n) || ! isscalar (n)) error ("list_primes: N must be a real scalar"); endif n = floor (n); if (n < 1) p = []; return; elseif (n == 1) p = 2; return; endif list = primes (n * log (5 * n)); if (numel (list) < n) ## Algorithm tested up to n=10,000 without failure. error ("list_primes: Algorithm failed. Try primes (n*log (6*n))(1:n)"); endif p = list(1:n); endfunction %!assert (list_primes (), [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, ... %! 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]) %!assert (list_primes (5), [2, 3, 5, 7, 11]) %!assert (list_primes (0), []) %!assert (list_primes (1), [2]) ## Test input validation %!error <N must be a real scalar> list_primes (i) %!error <N must be a real scalar> list_primes ([1 2])