Mercurial > hg > octave-lyh
annotate scripts/general/chop.m @ 14383:07c55bceca23 stable
Fix guarded_eval() subfunction in fminunc (bug #35534).
* fminunc.m: Fix guarded_eval() subfunction in fminunc (bug #35534).
| author | Olaf Till <olaf.till@uni-jena.de> |
|---|---|
| date | Wed, 15 Feb 2012 14:44:37 +0100 |
| parents | 4d917a6a858b |
| children | f3d52523cde1 |
| rev | line source |
|---|---|
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72c96de7a403
maint: update copyright notices for 2012
John W. Eaton <jwe@octave.org>
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1 ## Copyright (C) 2010-2012 John W. Eaton |
| 10203 | 2 ## |
| 3 ## This file is part of Octave. | |
| 4 ## | |
| 5 ## Octave is free software; you can redistribute it and/or modify it | |
| 6 ## under the terms of the GNU General Public License as published by | |
| 7 ## the Free Software Foundation; either version 3 of the License, or (at | |
| 8 ## your option) any later version. | |
| 9 ## | |
| 10 ## Octave is distributed in the hope that it will be useful, but | |
| 11 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 ## General Public License for more details. | |
| 14 ## | |
| 15 ## You should have received a copy of the GNU General Public License | |
| 16 ## along with Octave; see the file COPYING. If not, see | |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 18 | |
| 19 ## -*- texinfo -*- | |
|
11469
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Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
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20 ## @deftypefn {Function File} {} chop (@var{x}, @var{ndigits}, @var{base}) |
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c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
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diff
changeset
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21 ## Truncate elements of @var{x} to a length of @var{ndigits} such that the |
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c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
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22 ## resulting numbers are exactly divisible by @var{base}. If @var{base} is not |
| 10203 | 23 ## specified it defaults to 10. |
| 24 ## | |
| 25 ## @example | |
| 26 ## @group | |
| 27 ## chop (-pi, 5, 10) | |
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14327
4d917a6a858b
doc: Use Octave coding conventions in @example blocks of docstrings.
Rik <octave@nomad.inbox5.com>
parents:
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28 ## @result{} -3.14200000000000 |
| 10203 | 29 ## chop (-pi, 5, 5) |
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14327
4d917a6a858b
doc: Use Octave coding conventions in @example blocks of docstrings.
Rik <octave@nomad.inbox5.com>
parents:
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diff
changeset
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30 ## @result{} -3.14150000000000 |
| 10203 | 31 ## @end group |
| 32 ## @end example | |
| 33 ## @end deftypefn | |
| 34 | |
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11469
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Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
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35 function retval = chop (x, ndigits, base = 10) |
| 10203 | 36 |
| 37 if (nargin == 2 || nargin == 3) | |
| 38 tmp = abs (x); | |
| 39 | |
| 40 ## Avoid computing log (0). | |
| 41 tmp(x == 0) = 1; | |
| 42 | |
| 43 ## Digits to the left of the decimal. | |
| 44 tmp = floor (log10 (tmp) + 1); | |
| 45 | |
| 46 ## The expression | |
| 47 ## | |
| 48 ## round (x .* inflate) | |
| 49 ## | |
| 50 ## produces an integer that contains the digits we want to keep. | |
| 51 ## Multiplying by deflate puts the decimal back where it belngs. | |
| 52 ## | |
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11469
c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
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53 ## Further scaling and rounding with the base factor produces a |
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c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
|
54 ## value with ndigits exactly divisible by base. We skip that step |
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c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
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55 ## unless base was explicitly provided. |
| 10203 | 56 |
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11469
c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
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57 inflate = 10 .^ (ndigits - tmp); |
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c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
|
58 deflate = 10 .^ (tmp - ndigits); |
| 10203 | 59 if (nargin == 2) |
| 60 retval = deflate .* round (x .* inflate); | |
| 61 else | |
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11469
c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
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62 retval = base .* deflate .* round (round (x .* inflate) ./ base); |
| 10203 | 63 endif |
| 64 else | |
| 65 print_usage (); | |
| 66 endif | |
| 67 | |
| 68 endfunction | |
| 69 | |
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11469
c776f063fefe
Overhaul m-script files to use common variable name between code and documentation.
Rik <octave@nomad.inbox5.com>
parents:
10203
diff
changeset
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70 |
| 10203 | 71 %!assert (chop (e, 3), 2.72) |
| 72 %!assert (chop (e, 4), 2.718) | |
| 73 %!assert (chop (e, 4, 5), 2.72) | |
| 74 %!assert (chop (e, 4, 7), 2.716) | |
| 75 %!assert (chop (-e, 3), -2.72) | |
| 76 %!assert (chop (-e, 4), -2.718) | |
| 77 %!assert (chop (-e, 4, 5), -2.72) | |
| 78 %!assert (chop (-e, 4, 7), -2.716) | |
| 79 %!assert (chop (hilb (3), 3), [1,.5,.333;.5,.333,.25;.333,.25,.2]) | |
| 80 %!assert (chop (hilb (3), 2, 7), [.7,.49,.35;.49,.35,.28;.35,.28,.21], 2*eps) |