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comparison scripts/statistics/distributions/poissinv.m @ 11469:c776f063fefe

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Overhaul m-script files to use common variable name between code and documentation.
author Rik <octave@nomad.inbox5.com>
date Sun, 09 Jan 2011 12:41:21 -0800
parents 95c3e38098bf
children 1740012184f9
comparison
equal deleted inserted replaced
11468:e1edf0ba3bcb 11469:c776f063fefe
24 ## @end deftypefn 24 ## @end deftypefn
25 25
26 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> 26 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
27 ## Description: Quantile function of the Poisson distribution 27 ## Description: Quantile function of the Poisson distribution
28 28
29 function inv = poissinv (x, l) 29 function inv = poissinv (x, lambda)
30 30
31 if (nargin != 2) 31 if (nargin != 2)
32 print_usage (); 32 print_usage ();
33 endif 33 endif
34 34
35 if (!isscalar (l)) 35 if (!isscalar (lambda))
36 [retval, x, l] = common_size (x, l); 36 [retval, x, lambda] = common_size (x, lambda);
37 if (retval > 0) 37 if (retval > 0)
38 error ("poissinv: x and lambda must be of common size or scalar"); 38 error ("poissinv: x and lambda must be of common size or scalar");
39 endif 39 endif
40 endif 40 endif
41 41
42 inv = zeros (size (x)); 42 inv = zeros (size (x));
43 43
44 k = find ((x < 0) | (x > 1) | isnan (x) | !(l > 0)); 44 k = find ((x < 0) | (x > 1) | isnan (x) | !(lambda > 0));
45 if (any (k)) 45 if (any (k))
46 inv(k) = NaN; 46 inv(k) = NaN;
47 endif 47 endif
48 48
49 k = find ((x == 1) & (l > 0)); 49 k = find ((x == 1) & (lambda > 0));
50 if (any (k)) 50 if (any (k))
51 inv(k) = Inf; 51 inv(k) = Inf;
52 endif 52 endif
53 53
54 k = find ((x > 0) & (x < 1) & (l > 0)); 54 k = find ((x > 0) & (x < 1) & (lambda > 0));
55 if (any (k)) 55 if (any (k))
56 if (isscalar (l)) 56 if (isscalar (lambda))
57 cdf = exp (-l) * ones (size (k)); 57 cdf = exp (-lambda) * ones (size (k));
58 else 58 else
59 cdf = exp (-l(k)); 59 cdf = exp (-lambda(k));
60 endif 60 endif
61 while (1) 61 while (1)
62 m = find (cdf < x(k)); 62 m = find (cdf < x(k));
63 if (any (m)) 63 if (any (m))
64 inv(k(m)) = inv(k(m)) + 1; 64 inv(k(m)) = inv(k(m)) + 1;
65 if (isscalar (l)) 65 if (isscalar (lambda))
66 cdf(m) = cdf(m) + poisspdf (inv(k(m)), l); 66 cdf(m) = cdf(m) + poisspdf (inv(k(m)), lambda);
67 else 67 else
68 cdf(m) = cdf(m) + poisspdf (inv(k(m)), l(k(m))); 68 cdf(m) = cdf(m) + poisspdf (inv(k(m)), lambda(k(m)));
69 endif 69 endif
70 else 70 else
71 break; 71 break;
72 endif 72 endif
73 endwhile 73 endwhile