1 /** @File exam_pseries.cpp
3 * Series expansion test (Laurent and Taylor series). */
6 * GiNaC Copyright (C) 1999-2004 Johannes Gutenberg University Mainz, Germany
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
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13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27 static unsigned check_series(const ex &e, const ex &point, const ex &d, int order = 8)
29 ex es = e.series(x==point, order);
30 ex ep = ex_to<pseries>(es).convert_to_poly();
31 if (!(ep - d).expand().is_zero()) {
32 clog << "series expansion of " << e << " at " << point
33 << " erroneously returned " << ep << " (instead of " << d
35 clog << tree << (ep-d) << dflt;
42 static unsigned exam_series1()
50 d = x - pow(x, 3) / 6 + pow(x, 5) / 120 - pow(x, 7) / 5040 + Order(pow(x, 8));
51 result += check_series(e, 0, d);
54 d = 1 - pow(x, 2) / 2 + pow(x, 4) / 24 - pow(x, 6) / 720 + Order(pow(x, 8));
55 result += check_series(e, 0, d);
58 d = 1 + x + pow(x, 2) / 2 + pow(x, 3) / 6 + pow(x, 4) / 24 + pow(x, 5) / 120 + pow(x, 6) / 720 + pow(x, 7) / 5040 + Order(pow(x, 8));
59 result += check_series(e, 0, d);
62 d = 1 + x + pow(x, 2) + pow(x, 3) + pow(x, 4) + pow(x, 5) + pow(x, 6) + pow(x, 7) + Order(pow(x, 8));
63 result += check_series(e, 0, d);
67 result += check_series(e, 0, d);
70 d = 2 + pow(x-1, 2) - pow(x-1, 3) + pow(x-1, 4) - pow(x-1, 5) + pow(x-1, 6) - pow(x-1, 7) + Order(pow(x-1, 8));
71 result += check_series(e, 1, d);
73 e = pow(x + pow(x, 3), -1);
74 d = pow(x, -1) - x + pow(x, 3) - pow(x, 5) + pow(x, 7) + Order(pow(x, 8));
75 result += check_series(e, 0, d);
77 e = pow(pow(x, 2) + pow(x, 4), -1);
78 d = pow(x, -2) - 1 + pow(x, 2) - pow(x, 4) + pow(x, 6) + Order(pow(x, 8));
79 result += check_series(e, 0, d);
82 d = pow(x, -2) + numeric(1,3) + pow(x, 2) / 15 + pow(x, 4) * 2/189 + pow(x, 6) / 675 + Order(pow(x, 8));
83 result += check_series(e, 0, d);
86 d = x + pow(x, 3) / 3 + pow(x, 5) * 2/15 + pow(x, 7) * 17/315 + Order(pow(x, 8));
87 result += check_series(e, 0, d);
90 d = pow(x, -1) - x / 3 - pow(x, 3) / 45 - pow(x, 5) * 2/945 - pow(x, 7) / 4725 + Order(pow(x, 8));
91 result += check_series(e, 0, d);
93 e = pow(numeric(2), x);
95 d = 1 + t + pow(t, 2) / 2 + pow(t, 3) / 6 + pow(t, 4) / 24 + pow(t, 5) / 120 + pow(t, 6) / 720 + pow(t, 7) / 5040 + Order(pow(x, 8));
96 result += check_series(e, 0, d.expand());
100 d = 1 + t + pow(t, 2) / 2 + pow(t, 3) / 6 + pow(t, 4) / 24 + pow(t, 5) / 120 + pow(t, 6) / 720 + pow(t, 7) / 5040 + Order(pow(x, 8));
101 result += check_series(e, 0, d.expand());
105 result += check_series(e, 0, d, 1);
106 result += check_series(e, 0, d, 2);
108 e = pow(x, 8) * pow(pow(x,3)+ pow(x + pow(x,3), 2), -2);
109 d = pow(x, 4) - 2*pow(x, 5) + Order(pow(x, 6));
110 result += check_series(e, 0, d, 6);
112 e = cos(x) * pow(sin(x)*(pow(x, 5) + 4 * pow(x, 2)), -3);
113 d = pow(x, -9) / 64 - 3 * pow(x, -6) / 256 - pow(x, -5) / 960 + 535 * pow(x, -3) / 96768
114 + pow(x, -2) / 1280 - pow(x, -1) / 14400 - numeric(283, 129024) - 2143 * x / 5322240
116 result += check_series(e, 0, d, 2);
118 e = sqrt(1+x*x) * sqrt(1+2*x*x);
119 d = 1 + Order(pow(x, 2));
120 result += check_series(e, 0, d, 2);
123 e = pow(x, 4) * sin(a) + pow(x, 2);
124 d = pow(x, 2) + Order(pow(x, 3));
125 result += check_series(e, 0, d, 3);
131 static unsigned exam_series2()
136 e = pow(sin(x), -1).series(x==0, 8) + pow(sin(-x), -1).series(x==0, 12);
137 d = Order(pow(x, 8));
138 result += check_series(e, 0, d);
143 // Series multiplication
144 static unsigned exam_series3()
149 e = sin(x).series(x==0, 8) * pow(sin(x), -1).series(x==0, 12);
150 d = 1 + Order(pow(x, 7));
151 result += check_series(e, 0, d);
156 // Series exponentiation
157 static unsigned exam_series4()
162 e = pow((2*cos(x)).series(x==0, 5), 2).series(x==0, 5);
163 d = 4 - 4*pow(x, 2) + 4*pow(x, 4)/3 + Order(pow(x, 5));
164 result += check_series(e, 0, d);
166 e = pow(tgamma(x), 2).series(x==0, 2);
167 d = pow(x,-2) - 2*Euler/x + (pow(Pi,2)/6+2*pow(Euler,2))
168 + x*(-4*pow(Euler, 3)/3 -pow(Pi,2)*Euler/3 - 2*zeta(3)/3) + Order(pow(x, 2));
169 result += check_series(e, 0, d);
174 // Order term handling
175 static unsigned exam_series5()
180 e = 1 + x + pow(x, 2) + pow(x, 3);
182 result += check_series(e, 0, d, 0);
184 result += check_series(e, 0, d, 1);
185 d = 1 + x + Order(pow(x, 2));
186 result += check_series(e, 0, d, 2);
187 d = 1 + x + pow(x, 2) + Order(pow(x, 3));
188 result += check_series(e, 0, d, 3);
189 d = 1 + x + pow(x, 2) + pow(x, 3);
190 result += check_series(e, 0, d, 4);
194 // Series expansion of tgamma(-1)
195 static unsigned exam_series6()
198 ex d = pow(x+1,-1)*numeric(1,4) +
199 pow(x+1,0)*(numeric(3,4) -
200 numeric(1,2)*Euler) +
201 pow(x+1,1)*(numeric(7,4) -
203 numeric(1,2)*pow(Euler,2) +
204 numeric(1,12)*pow(Pi,2)) +
205 pow(x+1,2)*(numeric(15,4) -
207 numeric(1,3)*pow(Euler,3) +
208 numeric(1,4)*pow(Pi,2) +
209 numeric(3,2)*pow(Euler,2) -
210 numeric(1,6)*pow(Pi,2)*Euler -
211 numeric(2,3)*zeta(3)) +
212 pow(x+1,3)*(numeric(31,4) - pow(Euler,3) -
213 numeric(15,2)*Euler +
214 numeric(1,6)*pow(Euler,4) +
215 numeric(7,2)*pow(Euler,2) +
216 numeric(7,12)*pow(Pi,2) -
217 numeric(1,2)*pow(Pi,2)*Euler -
219 numeric(1,6)*pow(Euler,2)*pow(Pi,2) +
220 numeric(1,40)*pow(Pi,4) +
221 numeric(4,3)*zeta(3)*Euler) +
223 return check_series(e, -1, d, 4);
226 // Series expansion of tan(x==Pi/2)
227 static unsigned exam_series7()
230 ex d = pow(x-1,-1)/Pi*(-2) + pow(x-1,1)*Pi/6 + pow(x-1,3)*pow(Pi,3)/360
231 +pow(x-1,5)*pow(Pi,5)/15120 + pow(x-1,7)*pow(Pi,7)/604800
233 return check_series(e,1,d,9);
236 // Series expansion of log(sin(x==0))
237 static unsigned exam_series8()
240 ex d = log(x) - pow(x,2)/6 - pow(x,4)/180 - pow(x,6)/2835 - pow(x,8)/37800 + Order(pow(x,9));
241 return check_series(e,0,d,9);
244 // Series expansion of Li2(sin(x==0))
245 static unsigned exam_series9()
248 ex d = x + pow(x,2)/4 - pow(x,3)/18 - pow(x,4)/48
249 - 13*pow(x,5)/1800 - pow(x,6)/360 - 23*pow(x,7)/21168
251 return check_series(e,0,d,8);
254 // Series expansion of Li2((x==2)^2), caring about branch-cut
255 static unsigned exam_series10()
259 ex e = Li2(pow(x,2));
260 ex d = Li2(4) + (-log(3) + I*Pi*csgn(I-I*pow(x,2))) * (x-2)
261 + (numeric(-2,3) + log(3)/4 - I*Pi/4*csgn(I-I*pow(x,2))) * pow(x-2,2)
262 + (numeric(11,27) - log(3)/12 + I*Pi/12*csgn(I-I*pow(x,2))) * pow(x-2,3)
263 + (numeric(-155,648) + log(3)/32 - I*Pi/32*csgn(I-I*pow(x,2))) * pow(x-2,4)
265 return check_series(e,2,d,5);
268 // Series expansion of logarithms around branch points
269 static unsigned exam_series11()
279 result += check_series(e,0,d,5);
283 result += check_series(e,0,d,5);
287 result += check_series(e,0,d,5);
289 // These ones must not be expanded because it would result in a branch cut
290 // running in the wrong direction. (Other systems tend to get this wrong.)
293 result += check_series(e,0,d,5);
297 result += check_series(e,123,d,5);
300 d = e; // we don't know anything about a!
301 result += check_series(e,0,d,5);
304 d = log(1-x) - (x-1) + pow(x-1,2)/2 - pow(x-1,3)/3 + pow(x-1,4)/4 + Order(pow(x-1,5));
305 result += check_series(e,1,d,5);
310 // Series expansion of other functions around branch points
311 static unsigned exam_series12()
318 // NB: Mma and Maple give different results, but they agree if one
319 // takes into account that by assumption |x|<1.
321 d = (I*log(2)/2-I*log(1+I*x)/2) + (x-I)/4 + I*pow(x-I,2)/16 + Order(pow(x-I,3));
322 result += check_series(e,I,d,3);
324 // NB: here, at -I, Mathematica disagrees, but it is wrong -- they
325 // pick up a complex phase by incorrectly expanding logarithms.
327 d = (-I*log(2)/2+I*log(1-I*x)/2) + (x+I)/4 - I*pow(x+I,2)/16 + Order(pow(x+I,3));
328 result += check_series(e,-I,d,3);
330 // This is basically the same as above, the branch point is at +/-1:
332 d = (-log(2)/2+log(x+1)/2) + (x+1)/4 + pow(x+1,2)/16 + Order(pow(x+1,3));
333 result += check_series(e,-1,d,3);
339 unsigned exam_pseries()
343 cout << "examining series expansion" << flush;
344 clog << "----------series expansion:" << endl;
346 result += exam_series1(); cout << '.' << flush;
347 result += exam_series2(); cout << '.' << flush;
348 result += exam_series3(); cout << '.' << flush;
349 result += exam_series4(); cout << '.' << flush;
350 result += exam_series5(); cout << '.' << flush;
351 result += exam_series6(); cout << '.' << flush;
352 result += exam_series7(); cout << '.' << flush;
353 result += exam_series8(); cout << '.' << flush;
354 result += exam_series9(); cout << '.' << flush;
355 result += exam_series10(); cout << '.' << flush;
356 result += exam_series11(); cout << '.' << flush;
357 result += exam_series12(); cout << '.' << flush;
360 cout << " passed " << endl;
361 clog << "(no output)" << endl;
363 cout << " failed " << endl;