Mercurial > hg > octave-lyh
annotate scripts/specfun/pow2.m @ 9141:c1fff751b5a8
Update section 17.1 (Utility Functions) of arith.txi
Split section into "Exponents and Logarithms" and "Utility Functions"
Use Tex in many more of the doc strings for pretty printing in pdf format.
| author | Rik <rdrider0-list@yahoo.com> |
|---|---|
| date | Mon, 20 Apr 2009 17:16:09 -0700 |
| parents | eb63fbe60fab |
| children | 1231b1762a9a |
| rev | line source |
|---|---|
| 8920 | 1 ## Copyright (C) 1995, 1996, 1999, 2000, 2002, 2004, 2005, 2006, 2007, |
| 2 ## 2008, 2009 Kurt Hornik | |
| 3426 | 3 ## |
| 3922 | 4 ## This file is part of Octave. |
| 5 ## | |
| 6 ## Octave is free software; you can redistribute it and/or modify it | |
| 7 ## under the terms of the GNU General Public License as published by | |
| 7016 | 8 ## the Free Software Foundation; either version 3 of the License, or (at |
| 9 ## your option) any later version. | |
| 3426 | 10 ## |
| 3922 | 11 ## Octave is distributed in the hope that it will be useful, but |
| 2537 | 12 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 3426 | 14 ## General Public License for more details. |
| 15 ## | |
| 2537 | 16 ## You should have received a copy of the GNU General Public License |
| 7016 | 17 ## along with Octave; see the file COPYING. If not, see |
| 18 ## <http://www.gnu.org/licenses/>. | |
| 2537 | 19 |
| 3321 | 20 ## -*- texinfo -*- |
| 21 ## @deftypefn {Mapping Function} {} pow2 (@var{x}) | |
| 22 ## @deftypefnx {Mapping Function} {} pow2 (@var{f}, @var{e}) | |
| 23 ## With one argument, computes | |
| 24 ## @iftex | |
| 25 ## @tex | |
| 26 ## $2^x$ | |
| 27 ## @end tex | |
| 28 ## @end iftex | |
|
8517
81d6ab3ac93c
Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents:
7742
diff
changeset
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29 ## @ifnottex |
| 3321 | 30 ## 2 .^ x |
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8517
81d6ab3ac93c
Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents:
7742
diff
changeset
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31 ## @end ifnottex |
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9141
c1fff751b5a8
Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents:
8920
diff
changeset
|
32 ## for each element of @var{x}. |
|
c1fff751b5a8
Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents:
8920
diff
changeset
|
33 ## |
|
c1fff751b5a8
Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents:
8920
diff
changeset
|
34 ## With two arguments, returns |
| 3321 | 35 ## @iftex |
| 36 ## @tex | |
| 37 ## $f \cdot 2^e$. | |
| 38 ## @end tex | |
| 39 ## @end iftex | |
|
8517
81d6ab3ac93c
Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents:
7742
diff
changeset
|
40 ## @ifnottex |
| 3321 | 41 ## f .* (2 .^ e). |
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8517
81d6ab3ac93c
Allow documentation tobe built for other formats than tex and info
sh@sh-laptop
parents:
7742
diff
changeset
|
42 ## @end ifnottex |
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9141
c1fff751b5a8
Update section 17.1 (Utility Functions) of arith.txi
Rik <rdrider0-list@yahoo.com>
parents:
8920
diff
changeset
|
43 ## @seealso{log2, nextpow2} |
| 3321 | 44 ## @end deftypefn |
| 2537 | 45 |
| 46 ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> | |
| 47 ## Created: 17 October 1994 | |
| 48 ## Adapted-By: jwe | |
| 49 | |
| 50 function y = pow2 (f, e) | |
| 3426 | 51 |
| 2537 | 52 if (nargin == 1) |
| 53 y = 2 .^ f; | |
| 54 elseif (nargin == 2) | |
| 55 y = f .* (2 .^ e); | |
| 56 else | |
| 6046 | 57 print_usage (); |
| 2537 | 58 endif |
| 59 | |
| 60 endfunction | |
| 7385 | 61 |
| 62 %!test | |
| 63 %! x = [3, 0, -3]; | |
| 64 %! v = [8, 1, .125]; | |
| 65 %! assert(all (abs (pow2 (x) - v) < sqrt (eps))); | |
| 66 | |
| 67 %!test | |
| 68 %! x = [3, 0, -3, 4, 0, -4, 5, 0, -5]; | |
| 69 %! y = [-2, -2, -2, 1, 1, 1, 3, 3, 3]; | |
| 70 %! z = x .* (2 .^ y); | |
| 7742 | 71 %! assert(all (abs (pow2 (x,y) - z) < sqrt (eps))); |
| 7385 | 72 |
| 73 %!error pow2(); | |
| 74 |