annotate scripts/specfun/expint.m @ 20162:2645f9ef8c88 stable

doc: Update more docstrings to have one sentence summary as first line. Reviewed specfun, special-matrix, testfun, and time script directories. * scripts/specfun/expint.m, scripts/specfun/isprime.m, scripts/specfun/legendre.m, scripts/specfun/primes.m, scripts/specfun/reallog.m, scripts/specfun/realsqrt.m, scripts/special-matrix/gallery.m, scripts/special-matrix/hadamard.m, scripts/special-matrix/hankel.m, scripts/special-matrix/hilb.m, scripts/special-matrix/invhilb.m, scripts/special-matrix/magic.m, scripts/special-matrix/pascal.m, scripts/special-matrix/rosser.m, scripts/special-matrix/toeplitz.m, scripts/special-matrix/vander.m, scripts/special-matrix/wilkinson.m, scripts/testfun/assert.m, scripts/testfun/demo.m, scripts/testfun/example.m, scripts/testfun/fail.m, scripts/testfun/rundemos.m, scripts/testfun/runtests.m, scripts/testfun/speed.m, scripts/time/asctime.m, scripts/time/calendar.m, scripts/time/clock.m, scripts/time/ctime.m, scripts/time/datenum.m, scripts/time/datestr.m, scripts/time/datevec.m, scripts/time/etime.m, scripts/time/is_leap_year.m, scripts/time/now.m, scripts/time/weekday.m: Update more docstrings to have one sentence summary as first line.
author Rik <rik@octave.org>
date Sun, 03 May 2015 17:00:11 -0700
parents 446c46af4b42
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 ## Copyright (C) 2006, 2013 Sylvain Pelissier
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2 ##
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3 ## This file is part of Octave.
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4 ##
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5 ## Octave is free software; you can redistribute it and/or modify it
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6 ## under the terms of the GNU General Public License as published by
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7 ## the Free Software Foundation; either version 3 of the License, or (at
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8 ## your option) any later version.
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9 ##
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10 ## Octave is distributed in the hope that it will be useful, but
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 ## General Public License for more details.
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14 ##
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15 ## You should have received a copy of the GNU General Public License
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16 ## along with Octave; see the file COPYING. If not, see
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17 ## <http://www.gnu.org/licenses/>.
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18
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19 ## Author: Sylvain Pelissier <sylvain.pelissier@gmail.com>
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20
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21 ## -*- texinfo -*-
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22 ## @deftypefn {Function File} {} expint (@var{x})
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23 ## Compute the exponential integral:
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24 ## @tex
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25 ## $$
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26 ## {\rm E_1} (x) = \int_x^\infty {e^{-t} \over t} dt
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27 ## $$
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28 ## @end tex
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29 ## @ifnottex
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30 ##
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31 ## @example
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32 ## @group
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33 ## infinity
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34 ## /
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35 ## E_1 (x) = | exp (-t)/t dt
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36 ## /
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37 ## x
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38 ## @end group
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39 ## @end example
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40 ##
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41 ## @end ifnottex
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42 ## Note: For compatibility, this functions uses the @sc{matlab} definition
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43 ## of the exponential integral. Most other sources refer to this particular
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44 ## value as @math{E_1 (x)}, and the exponential integral as
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45 ## @tex
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46 ## $$
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47 ## {\rm Ei} (x) = - \int_{-x}^\infty {e^{-t} \over t} dt.
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48 ## $$
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49 ## @end tex
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50 ## @ifnottex
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51 ##
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52 ## @example
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53 ## @group
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54 ## infinity
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55 ## /
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56 ## Ei (x) = - | exp (-t)/t dt
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57 ## /
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58 ## -x
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59 ## @end group
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60 ## @end example
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61 ##
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62 ## @end ifnottex
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63 ## The two definitions are related, for positive real values of @var{x}, by
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64 ## @tex
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65 ## $
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66 ## E_1 (-x) = -{\rm Ei} (x) - i\pi.
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67 ## $
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68 ## @end tex
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69 ## @ifnottex
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70 ## @w{@code{E_1 (-x) = -Ei (x) - i*pi}}.
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71 ## @end ifnottex
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72 ## @end deftypefn
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73
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74 function y = expint (x)
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75
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76 if (nargin != 1)
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77 print_usage ();
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78 endif
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79
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80 y = x; # Copy over all values, including NaNs
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81
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82 if (isreal (x))
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83 idx = (x >= 0);
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84 y(idx) = -expint_Ei (-x(idx));
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85
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86 idx = (x < 0);
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87 y(idx) = -expint_Ei (-x(idx)) - i*pi;
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88 else
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89 idx = (imag (x) > 0);
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90 y(idx) = -expint_Ei (-x(idx)) - i*pi;
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91
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92 idx = (imag (x) < 0);
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93 y(idx) = -expint_Ei (-x(idx)) + i*pi;
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94
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95 isreal_idx = (imag (x) == 0);
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96 idx = (isreal_idx & real (x) >= 0);
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97 y(idx) = -expint_Ei (-x(idx));
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98
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99 idx = (isreal_idx & real (x) < 0);
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100 y(idx) = -expint_Ei (-x(idx)) - i*pi;
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101 endif
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102
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103 endfunction
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104
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105 ## -*- texinfo -*-
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106 ## @deftypefn {Function File} {@var{y} =} expint_Ei (@var{x})
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107 ## Compute the exponential integral:
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108 ## @verbatim
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109 ## infinity
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110 ## /
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111 ## expint_Ei (x) = - | exp(-t)/t dt
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112 ## /
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113 ## -x
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114 ## @end verbatim
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115 ## @end deftypefn
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116
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117 function y = expint_Ei (x)
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118
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119 y = zeros (size (x));
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120 F = @(x) exp (-x)./x;
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121
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122 for t = 1:numel (x)
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123 xt = x(t);
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124 if (xt < 0 && imag (xt) == 0)
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125 ## Direct integration for most real inputs
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126 y(t) = -quad (F, -xt, Inf, [0, 1e-10]);
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127 elseif (xt > 2 && imag (xt) == 0)
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128 persistent Ei_2 = 4.954234356001890;
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129 y(t) = Ei_2 - quad (F, -xt, -2);
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130 elseif (abs (xt) < 10)
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131 ## Series Expansion for real (range [0,2]) or complex inputs (r < 10)
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132 k = 1;
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133 do
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134 term = xt^k / (k*factorial (k));
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135 y(t) += term;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
136 until (abs (term) < eps (abs (y(t))) / 2 || k++ >= 100)
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
137 y(t) = 0.57721566490153286 + log (xt) + y(t);
16584
2f766ceeb03e Add ellipj, ellipke, and expint functions from Octave Forge
Mike Miller <mtmiller@ieee.org>
parents:
diff changeset
138 else
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
139 ## FIXME: This expansion is accurate to only 1e-13 at the beginning
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
140 ## near 10+i, although it becomes more accurate as the magnitude
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
141 ## of xt grows.
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
142 if (imag (xt) <= 0)
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
143 persistent a1 = 4.03640;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
144 persistent a2 = 1.15198;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
145 persistent b1 = 5.03637;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
146 persistent b2 = 4.19160;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
147 y(t) = -(xt^2 - a1*xt + a2) ...
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
148 / ((xt^2 - b1*xt + b2) * (-xt) * exp (-xt)) ...
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
149 - i*pi;
16584
2f766ceeb03e Add ellipj, ellipke, and expint functions from Octave Forge
Mike Miller <mtmiller@ieee.org>
parents:
diff changeset
150 else
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
151 y(t) = conj (expint_Ei (conj (xt)));
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
152 endif;
16584
2f766ceeb03e Add ellipj, ellipke, and expint functions from Octave Forge
Mike Miller <mtmiller@ieee.org>
parents:
diff changeset
153 endif
2f766ceeb03e Add ellipj, ellipke, and expint functions from Octave Forge
Mike Miller <mtmiller@ieee.org>
parents:
diff changeset
154 endfor
2f766ceeb03e Add ellipj, ellipke, and expint functions from Octave Forge
Mike Miller <mtmiller@ieee.org>
parents:
diff changeset
155 endfunction
16585
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
156
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
157
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
158 ## Test against A&S Table 5.1
16585
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
159 %!test
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
160 %! x = [5:5:50]'/100;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
161 %! gamma = 0.5772156649;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
162 %! y_exp = [0.9876375971;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
163 %! 0.9755453033;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
164 %! 0.9637156702;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
165 %! 0.9521414833;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
166 %! 0.9408157528;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
167 %! 0.9297317075;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
168 %! 0.9188827858;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
169 %! 0.9082626297;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
170 %! 0.8978650778;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
171 %! 0.8876841584 ];
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
172 %! y = (expint (x) + log(x) + gamma) ./ x;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
173 %! assert (y, y_exp, 1e-9);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
174 %!test
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
175 %! x = [50:5:95]'/100;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
176 %! y_exp = [0.559773595;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
177 %! 0.503364081;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
178 %! 0.454379503;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
179 %! 0.411516976;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
180 %! 0.373768843;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
181 %! 0.340340813;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
182 %! 0.310596579;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
183 %! 0.284019269;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
184 %! 0.260183939;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
185 %! 0.238737524 ];
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
186 %! y = expint (x);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
187 %! assert (y, y_exp, 1e-9);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
188 %!test
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
189 %! x = [100:5:145]'/100;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
190 %! y_exp = [0.219383934;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
191 %! 0.201872813;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
192 %! 0.185990905;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
193 %! 0.171555354;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
194 %! 0.158408437;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
195 %! 0.146413373;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
196 %! 0.135450958;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
197 %! 0.125416844;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
198 %! 0.116219313;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
199 %! 0.107777440 ];
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
200 %! y = expint (x);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
201 %! assert (y, y_exp, 1e-9);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
202 %!test
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
203 %! x = [150:5:200]'/100;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
204 %! y_exp = [0.100019582;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
205 %! 0.092882108;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
206 %! 0.086308334;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
207 %! 0.080247627;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
208 %! 0.074654644;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
209 %! 0.069488685;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
210 %! 0.064713129;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
211 %! 0.060294967;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
212 %! 0.056204378;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
213 %! 0.052414380;
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
214 %! 0.048900511 ];
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
215 %! y = expint (x);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
216 %! assert (y, y_exp, 1e-9);
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
217
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
218 ## Series expansion (-2 < x < 0)
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
219 ## Expected values from Mathematica
19593
446c46af4b42 strip trailing whitespace from most source files
John W. Eaton <jwe@octave.org>
parents: 17744
diff changeset
220 %!test
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
221 %! x = [-0.1; -0.5; -1; -1.5; -2];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
222 %! y_exp = [ 1.6228128139692767 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
223 %! -0.45421990486317358 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
224 %! -1.8951178163559368 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
225 %! -3.3012854491297978 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
226 %! -4.9542343560018902 - i*pi];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
227 %! y = expint (x);
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
228 %! assert (y, y_exp, eps (real (y_exp)));
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
229
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
230 ## (x < -2, x real)
19593
446c46af4b42 strip trailing whitespace from most source files
John W. Eaton <jwe@octave.org>
parents: 17744
diff changeset
231 %!test
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
232 %! x = [-2.5; -3; -10;-15; -25];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
233 %! y_exp = [-7.0737658945786007 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
234 %! -9.9338325706254165 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
235 %! -2492.2289762418777 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
236 %! -234955.85249076830 - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
237 %! -3.0059509065255486e9 - i*pi];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
238 %! y = expint (x);
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
239 %! assert (y, y_exp, 8*eps (real (y_exp)));
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
240
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
241 ## Complex values
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
242 %!test
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
243 %! x = [i; -1-i; 10-i; 10+i];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
244 %! y_exp = [-0.33740392290096813 - i*0.62471325642771360;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
245 %! -1.7646259855638540 + i*0.75382280207927082;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
246 %! 1.90746381979783120e-6 + i*3.67354374003294739e-6;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
247 %! 1.90746381979783120e-6 - i*3.67354374003294739e-6];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
248 %! y = expint (x);
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
249 %! assert (y, y_exp, 1e-12);
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
250
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
251 ## Exceptional values (-Inf, Inf, NaN, 0, 0.37250741078)
19593
446c46af4b42 strip trailing whitespace from most source files
John W. Eaton <jwe@octave.org>
parents: 17744
diff changeset
252 %!test
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
253 %! x = [-Inf; Inf; NaN; 0; -0.3725074107813668];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
254 %! y_exp = [-Inf - i*pi;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
255 %! -Inf; # should be 0;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
256 %! NaN;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
257 %! Inf;
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
258 %! 0 - i*pi];
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
259 %! y = expint (x);
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
260 %! assert (y, y_exp, 5*eps);
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
261
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
262 ## Test input validation
16585
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
263 %!error expint ()
1a3bfb14b5da Add and fix tests for ellipj, ellipke, and expint
Mike Miller <mtmiller@ieee.org>
parents: 16584
diff changeset
264 %!error expint (1,2)
17338
1c89599167a6 maint: End m-files with 1 blank line.
Rik <rik@octave.org>
parents: 16768
diff changeset
265
17363
9aca7020c89f expint.m: Overhaul function.
Rik <rik@octave.org>
parents: 17338
diff changeset
266