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comparison scripts/general/shift.m @ 13278:04edb15d7966

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shift.m: Clean up code and add more tests * shift.m: Shift input validation to front of function. Add more tests for input validation. Tweak algorithm to avoid one unecessary calculation when the shift is 0 and add test for that.
author Rik <octave@nomad.inbox5.com>
date Wed, 05 Oct 2011 12:00:31 -0700
parents 2783fa95cab7
children c479e3d0311f
comparison
equal deleted inserted replaced
13277:9f2e568123ea 13278:04edb15d7966
35 35
36 if (nargin != 2 && nargin != 3) 36 if (nargin != 2 && nargin != 3)
37 print_usage (); 37 print_usage ();
38 endif 38 endif
39 39
40 if (! (isscalar (b) && b == round (b))) 40 if (numel (x) < 1)
41 error ("shift: X must not be empty");
42 elseif (! (isscalar (b) && b == fix (b)))
41 error ("shift: B must be an integer"); 43 error ("shift: B must be an integer");
42 endif 44 endif
43 45
44 nd = ndims (x); 46 nd = ndims (x);
45 sz = size (x); 47 sz = size (x);
46 48
47 if (nargin == 3) 49 if (nargin == 3)
48 if (!(isscalar (dim) && dim == round (dim)) 50 if (!(isscalar (dim) && dim == fix (dim))
49 || !(1 <= dim && dim <= nd)) 51 || !(1 <= dim && dim <= nd))
50 error ("shift: DIM must be an integer and a valid dimension"); 52 error ("shift: DIM must be an integer and a valid dimension");
51 endif 53 endif
52 else 54 else
53 ## Find the first non-singleton dimension. 55 ## Find the first non-singleton dimension.
54 (dim = find (sz > 1, 1)) || (dim = 1); 56 (dim = find (sz > 1, 1)) || (dim = 1);
55 endif 57 endif
56 58
57 if (numel (x) < 1) 59 d = sz(dim);
58 error ("shift: X must not be empty");
59 endif
60
61 d = sz (dim);
62 60
63 idx = repmat ({':'}, nd, 1); 61 idx = repmat ({':'}, nd, 1);
64 if (b >= 0) 62 if (b > 0)
65 b = rem (b, d); 63 b = rem (b, d);
66 idx{dim} = [d-b+1:d, 1:d-b]; 64 idx{dim} = [d-b+1:d, 1:d-b];
67 elseif (b < 0) 65 elseif (b < 0)
68 b = rem (abs (b), d); 66 b = rem (abs (b), d);
69 idx{dim} = [b+1:d, 1:b]; 67 idx{dim} = [b+1:d, 1:b];
70 endif 68 endif
69
71 y = x(idx{:}); 70 y = x(idx{:});
72 71
73 endfunction 72 endfunction
73
74 74
75 %!test 75 %!test
76 %! a = [1, 2, 3]; 76 %! a = [1, 2, 3];
77 %! b = [4, 5, 6]; 77 %! b = [4, 5, 6];
78 %! c = [7, 8, 9]; 78 %! c = [7, 8, 9];
79 %! 79 %!
80 %! r = [a, b, c]; 80 %! r = [a, b, c];
81 %! m = [a; b; c]; 81 %! m = [a; b; c];
82 %! 82 %!
83 %! assert((shift (r, 3) == [c, a, b] 83 %! assert(shift (r, 0), r);
84 %! && shift (r, -6) == [c, a, b] 84 %! assert(shift (r, 3), [c, a, b]);
85 %! && shift (r, -3) == [b, c, a] 85 %! assert(shift (r, -6), [c, a, b]);
86 %! && shift (m, 1) == [c; a; b] 86 %! assert(shift (r, -3), [b, c, a]);
87 %! && shift (m, -2) == [c; a; b])); 87 %! assert(shift (m, 1), [c; a; b]);
88 %! assert(shift (m, -2), [c; a; b]);
88 89
89 %!error shift (); 90 %% Test input validation
91 %!error shift ()
92 %!error shift (1, 2, 3, 4)
93 %!error shift ([], 1)
94 %!error shift (ones(2), ones(2))
95 %!error kurtosis (ones(2), 1.5)
96 %!error kurtosis (ones(2), 0)
97 %!error kurtosis (ones(2), 3)
90 98
91 %!error shift (1, 2, 3, 4);
92