Commit | Line | Data |
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1 | # $RCSFile$ |
2 | # |
3 | # Complex numbers and associated mathematical functions |
0c721ce2 |
4 | # -- Raphael Manfredi, September 1996 |
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5 | # -- Jarkko Hietaniemi, March-April 1997 |
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6 | |
7 | require Exporter; |
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8 | package Math::Complex; |
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9 | |
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10 | use strict; |
11 | |
5aabfad6 |
12 | use vars qw($VERSION @ISA |
13 | @EXPORT %EXPORT_TAGS |
14 | $package $display |
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15 | $i $logn %logn); |
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16 | |
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17 | @ISA = qw(Exporter); |
18 | |
19 | $VERSION = 1.01; |
20 | |
21 | my @trig = qw( |
22 | pi |
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23 | sin cos tan |
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24 | csc cosec sec cot cotan |
25 | asin acos atan |
26 | acsc acosec asec acot acotan |
27 | sinh cosh tanh |
28 | csch cosech sech coth cotanh |
29 | asinh acosh atanh |
30 | acsch acosech asech acoth acotanh |
31 | ); |
32 | |
33 | @EXPORT = (qw( |
34 | i Re Im arg |
35 | sqrt exp log ln |
36 | log10 logn cbrt root |
37 | cplx cplxe |
38 | ), |
39 | @trig); |
40 | |
41 | %EXPORT_TAGS = ( |
42 | 'trig' => [@trig], |
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43 | ); |
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44 | |
a5f75d66 |
45 | use overload |
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46 | '+' => \&plus, |
47 | '-' => \&minus, |
48 | '*' => \&multiply, |
49 | '/' => \÷, |
66730be0 |
50 | '**' => \&power, |
51 | '<=>' => \&spaceship, |
52 | 'neg' => \&negate, |
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53 | '~' => \&conjugate, |
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54 | 'abs' => \&abs, |
55 | 'sqrt' => \&sqrt, |
56 | 'exp' => \&exp, |
57 | 'log' => \&log, |
58 | 'sin' => \&sin, |
59 | 'cos' => \&cos, |
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60 | 'tan' => \&tan, |
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61 | 'atan2' => \&atan2, |
62 | qw("" stringify); |
63 | |
64 | # |
65 | # Package globals |
66 | # |
67 | |
68 | $package = 'Math::Complex'; # Package name |
69 | $display = 'cartesian'; # Default display format |
70 | |
71 | # |
72 | # Object attributes (internal): |
73 | # cartesian [real, imaginary] -- cartesian form |
74 | # polar [rho, theta] -- polar form |
75 | # c_dirty cartesian form not up-to-date |
76 | # p_dirty polar form not up-to-date |
77 | # display display format (package's global when not set) |
78 | # |
79 | |
80 | # |
81 | # ->make |
82 | # |
83 | # Create a new complex number (cartesian form) |
84 | # |
85 | sub make { |
86 | my $self = bless {}, shift; |
87 | my ($re, $im) = @_; |
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88 | $self->{'cartesian'} = [$re, $im]; |
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89 | $self->{c_dirty} = 0; |
90 | $self->{p_dirty} = 1; |
91 | return $self; |
92 | } |
93 | |
94 | # |
95 | # ->emake |
96 | # |
97 | # Create a new complex number (exponential form) |
98 | # |
99 | sub emake { |
100 | my $self = bless {}, shift; |
101 | my ($rho, $theta) = @_; |
102 | $theta += pi() if $rho < 0; |
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103 | $self->{'polar'} = [abs($rho), $theta]; |
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104 | $self->{p_dirty} = 0; |
105 | $self->{c_dirty} = 1; |
106 | return $self; |
107 | } |
108 | |
109 | sub new { &make } # For backward compatibility only. |
110 | |
111 | # |
112 | # cplx |
113 | # |
114 | # Creates a complex number from a (re, im) tuple. |
115 | # This avoids the burden of writing Math::Complex->make(re, im). |
116 | # |
117 | sub cplx { |
118 | my ($re, $im) = @_; |
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119 | return $package->make($re, defined $im ? $im : 0); |
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120 | } |
121 | |
122 | # |
123 | # cplxe |
124 | # |
125 | # Creates a complex number from a (rho, theta) tuple. |
126 | # This avoids the burden of writing Math::Complex->emake(rho, theta). |
127 | # |
128 | sub cplxe { |
129 | my ($rho, $theta) = @_; |
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130 | return $package->emake($rho, defined $theta ? $theta : 0); |
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131 | } |
132 | |
133 | # |
134 | # pi |
135 | # |
136 | # The number defined as 2 * pi = 360 degrees |
137 | # |
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138 | |
139 | use constant pi => 4 * atan2(1, 1); |
140 | |
141 | # |
142 | # log2inv |
143 | # |
144 | # Used in log10(). |
145 | # |
146 | |
147 | use constant log10inv => 1 / log(10); |
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148 | |
149 | # |
150 | # i |
151 | # |
152 | # The number defined as i*i = -1; |
153 | # |
154 | sub i () { |
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155 | return $i if ($i); |
156 | $i = bless {}; |
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157 | $i->{'cartesian'} = [0, 1]; |
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158 | $i->{'polar'} = [1, pi/2]; |
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159 | $i->{c_dirty} = 0; |
160 | $i->{p_dirty} = 0; |
161 | return $i; |
162 | } |
163 | |
164 | # |
165 | # Attribute access/set routines |
166 | # |
167 | |
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168 | sub cartesian {$_[0]->{c_dirty} ? |
169 | $_[0]->update_cartesian : $_[0]->{'cartesian'}} |
170 | sub polar {$_[0]->{p_dirty} ? |
171 | $_[0]->update_polar : $_[0]->{'polar'}} |
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172 | |
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173 | sub set_cartesian { $_[0]->{p_dirty}++; $_[0]->{'cartesian'} = $_[1] } |
174 | sub set_polar { $_[0]->{c_dirty}++; $_[0]->{'polar'} = $_[1] } |
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175 | |
176 | # |
177 | # ->update_cartesian |
178 | # |
179 | # Recompute and return the cartesian form, given accurate polar form. |
180 | # |
181 | sub update_cartesian { |
182 | my $self = shift; |
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183 | my ($r, $t) = @{$self->{'polar'}}; |
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184 | $self->{c_dirty} = 0; |
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185 | return $self->{'cartesian'} = [$r * cos $t, $r * sin $t]; |
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186 | } |
187 | |
188 | # |
189 | # |
190 | # ->update_polar |
191 | # |
192 | # Recompute and return the polar form, given accurate cartesian form. |
193 | # |
194 | sub update_polar { |
195 | my $self = shift; |
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196 | my ($x, $y) = @{$self->{'cartesian'}}; |
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197 | $self->{p_dirty} = 0; |
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198 | return $self->{'polar'} = [0, 0] if $x == 0 && $y == 0; |
199 | return $self->{'polar'} = [sqrt($x*$x + $y*$y), atan2($y, $x)]; |
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200 | } |
201 | |
202 | # |
203 | # (plus) |
204 | # |
205 | # Computes z1+z2. |
206 | # |
207 | sub plus { |
208 | my ($z1, $z2, $regular) = @_; |
209 | my ($re1, $im1) = @{$z1->cartesian}; |
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210 | my ($re2, $im2) = ref $z2 ? @{$z2->cartesian} : ($z2, 0); |
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211 | unless (defined $regular) { |
212 | $z1->set_cartesian([$re1 + $re2, $im1 + $im2]); |
213 | return $z1; |
214 | } |
215 | return (ref $z1)->make($re1 + $re2, $im1 + $im2); |
216 | } |
217 | |
218 | # |
219 | # (minus) |
220 | # |
221 | # Computes z1-z2. |
222 | # |
223 | sub minus { |
224 | my ($z1, $z2, $inverted) = @_; |
225 | my ($re1, $im1) = @{$z1->cartesian}; |
5cd24f17 |
226 | my ($re2, $im2) = ref $z2 ? @{$z2->cartesian} : ($z2, 0); |
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227 | unless (defined $inverted) { |
228 | $z1->set_cartesian([$re1 - $re2, $im1 - $im2]); |
229 | return $z1; |
230 | } |
231 | return $inverted ? |
232 | (ref $z1)->make($re2 - $re1, $im2 - $im1) : |
233 | (ref $z1)->make($re1 - $re2, $im1 - $im2); |
234 | } |
235 | |
236 | # |
237 | # (multiply) |
238 | # |
239 | # Computes z1*z2. |
240 | # |
241 | sub multiply { |
242 | my ($z1, $z2, $regular) = @_; |
243 | my ($r1, $t1) = @{$z1->polar}; |
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244 | my ($r2, $t2) = ref $z2 ? |
245 | @{$z2->polar} : (abs($z2), $z2 >= 0 ? 0 : pi); |
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246 | unless (defined $regular) { |
247 | $z1->set_polar([$r1 * $r2, $t1 + $t2]); |
248 | return $z1; |
249 | } |
250 | return (ref $z1)->emake($r1 * $r2, $t1 + $t2); |
251 | } |
252 | |
253 | # |
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254 | # divbyzero |
255 | # |
256 | # Die on division by zero. |
257 | # |
258 | sub divbyzero { |
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259 | my $mess = "$_[0]: Division by zero.\n"; |
260 | |
261 | if (defined $_[1]) { |
262 | $mess .= "(Because in the definition of $_[0], the divisor "; |
263 | $mess .= "$_[1] " unless ($_[1] eq '0'); |
264 | $mess .= "is 0)\n"; |
265 | } |
266 | |
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267 | my @up = caller(1); |
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268 | |
269 | $mess .= "Died at $up[1] line $up[2].\n"; |
270 | |
271 | die $mess; |
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272 | } |
273 | |
274 | # |
66730be0 |
275 | # (divide) |
276 | # |
277 | # Computes z1/z2. |
278 | # |
279 | sub divide { |
280 | my ($z1, $z2, $inverted) = @_; |
281 | my ($r1, $t1) = @{$z1->polar}; |
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282 | my ($r2, $t2) = ref $z2 ? |
283 | @{$z2->polar} : (abs($z2), $z2 >= 0 ? 0 : pi); |
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284 | unless (defined $inverted) { |
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285 | divbyzero "$z1/0" if ($r2 == 0); |
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286 | $z1->set_polar([$r1 / $r2, $t1 - $t2]); |
287 | return $z1; |
288 | } |
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289 | if ($inverted) { |
290 | divbyzero "$z2/0" if ($r1 == 0); |
291 | return (ref $z1)->emake($r2 / $r1, $t2 - $t1); |
292 | } else { |
293 | divbyzero "$z1/0" if ($r2 == 0); |
294 | return (ref $z1)->emake($r1 / $r2, $t1 - $t2); |
295 | } |
66730be0 |
296 | } |
297 | |
298 | # |
299 | # (power) |
300 | # |
301 | # Computes z1**z2 = exp(z2 * log z1)). |
302 | # |
303 | sub power { |
304 | my ($z1, $z2, $inverted) = @_; |
305 | return exp($z1 * log $z2) if defined $inverted && $inverted; |
306 | return exp($z2 * log $z1); |
307 | } |
308 | |
309 | # |
310 | # (spaceship) |
311 | # |
312 | # Computes z1 <=> z2. |
313 | # Sorts on the real part first, then on the imaginary part. Thus 2-4i > 3+8i. |
314 | # |
315 | sub spaceship { |
316 | my ($z1, $z2, $inverted) = @_; |
5cd24f17 |
317 | my ($re1, $im1) = ref $z1 ? @{$z1->cartesian} : ($z1, 0); |
318 | my ($re2, $im2) = ref $z2 ? @{$z2->cartesian} : ($z2, 0); |
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319 | my $sgn = $inverted ? -1 : 1; |
320 | return $sgn * ($re1 <=> $re2) if $re1 != $re2; |
321 | return $sgn * ($im1 <=> $im2); |
322 | } |
323 | |
324 | # |
325 | # (negate) |
326 | # |
327 | # Computes -z. |
328 | # |
329 | sub negate { |
330 | my ($z) = @_; |
331 | if ($z->{c_dirty}) { |
332 | my ($r, $t) = @{$z->polar}; |
333 | return (ref $z)->emake($r, pi + $t); |
334 | } |
335 | my ($re, $im) = @{$z->cartesian}; |
336 | return (ref $z)->make(-$re, -$im); |
337 | } |
338 | |
339 | # |
340 | # (conjugate) |
341 | # |
342 | # Compute complex's conjugate. |
343 | # |
344 | sub conjugate { |
345 | my ($z) = @_; |
346 | if ($z->{c_dirty}) { |
347 | my ($r, $t) = @{$z->polar}; |
348 | return (ref $z)->emake($r, -$t); |
349 | } |
350 | my ($re, $im) = @{$z->cartesian}; |
351 | return (ref $z)->make($re, -$im); |
352 | } |
353 | |
354 | # |
355 | # (abs) |
356 | # |
357 | # Compute complex's norm (rho). |
358 | # |
359 | sub abs { |
360 | my ($z) = @_; |
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361 | return abs($z) unless ref $z; |
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362 | my ($r, $t) = @{$z->polar}; |
363 | return abs($r); |
364 | } |
365 | |
366 | # |
367 | # arg |
368 | # |
369 | # Compute complex's argument (theta). |
370 | # |
371 | sub arg { |
372 | my ($z) = @_; |
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373 | return ($z < 0 ? pi : 0) unless ref $z; |
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374 | my ($r, $t) = @{$z->polar}; |
375 | return $t; |
376 | } |
377 | |
378 | # |
379 | # (sqrt) |
380 | # |
0c721ce2 |
381 | # Compute sqrt(z). |
66730be0 |
382 | # |
383 | sub sqrt { |
384 | my ($z) = @_; |
0c721ce2 |
385 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
386 | my ($r, $t) = @{$z->polar}; |
387 | return (ref $z)->emake(sqrt($r), $t/2); |
388 | } |
389 | |
390 | # |
391 | # cbrt |
392 | # |
0c721ce2 |
393 | # Compute cbrt(z) (cubic root). |
66730be0 |
394 | # |
395 | sub cbrt { |
396 | my ($z) = @_; |
0c721ce2 |
397 | return cplx($z, 0) ** (1/3) unless ref $z; |
66730be0 |
398 | my ($r, $t) = @{$z->polar}; |
399 | return (ref $z)->emake($r**(1/3), $t/3); |
400 | } |
401 | |
402 | # |
403 | # root |
404 | # |
405 | # Computes all nth root for z, returning an array whose size is n. |
406 | # `n' must be a positive integer. |
407 | # |
408 | # The roots are given by (for k = 0..n-1): |
409 | # |
410 | # z^(1/n) = r^(1/n) (cos ((t+2 k pi)/n) + i sin ((t+2 k pi)/n)) |
411 | # |
412 | sub root { |
413 | my ($z, $n) = @_; |
414 | $n = int($n + 0.5); |
415 | return undef unless $n > 0; |
416 | my ($r, $t) = ref $z ? @{$z->polar} : (abs($z), $z >= 0 ? 0 : pi); |
417 | my @root; |
418 | my $k; |
419 | my $theta_inc = 2 * pi / $n; |
420 | my $rho = $r ** (1/$n); |
421 | my $theta; |
422 | my $complex = ref($z) || $package; |
423 | for ($k = 0, $theta = $t / $n; $k < $n; $k++, $theta += $theta_inc) { |
424 | push(@root, $complex->emake($rho, $theta)); |
a0d0e21e |
425 | } |
66730be0 |
426 | return @root; |
a0d0e21e |
427 | } |
428 | |
66730be0 |
429 | # |
430 | # Re |
431 | # |
432 | # Return Re(z). |
433 | # |
a0d0e21e |
434 | sub Re { |
66730be0 |
435 | my ($z) = @_; |
436 | return $z unless ref $z; |
437 | my ($re, $im) = @{$z->cartesian}; |
438 | return $re; |
a0d0e21e |
439 | } |
440 | |
66730be0 |
441 | # |
442 | # Im |
443 | # |
444 | # Return Im(z). |
445 | # |
a0d0e21e |
446 | sub Im { |
66730be0 |
447 | my ($z) = @_; |
448 | return 0 unless ref $z; |
449 | my ($re, $im) = @{$z->cartesian}; |
450 | return $im; |
a0d0e21e |
451 | } |
452 | |
66730be0 |
453 | # |
454 | # (exp) |
455 | # |
456 | # Computes exp(z). |
457 | # |
458 | sub exp { |
459 | my ($z) = @_; |
0c721ce2 |
460 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
461 | my ($x, $y) = @{$z->cartesian}; |
462 | return (ref $z)->emake(exp($x), $y); |
463 | } |
464 | |
465 | # |
466 | # (log) |
467 | # |
468 | # Compute log(z). |
469 | # |
470 | sub log { |
471 | my ($z) = @_; |
0c721ce2 |
472 | $z = cplx($z, 0) unless ref $z; |
0c721ce2 |
473 | my ($x, $y) = @{$z->cartesian}; |
5cd24f17 |
474 | my ($r, $t) = @{$z->polar}; |
0c721ce2 |
475 | $t -= 2 * pi if ($t > pi() and $x < 0); |
476 | $t += 2 * pi if ($t < -pi() and $x < 0); |
66730be0 |
477 | return (ref $z)->make(log($r), $t); |
478 | } |
479 | |
480 | # |
0c721ce2 |
481 | # ln |
482 | # |
483 | # Alias for log(). |
484 | # |
485 | sub ln { Math::Complex::log(@_) } |
486 | |
487 | # |
66730be0 |
488 | # log10 |
489 | # |
490 | # Compute log10(z). |
491 | # |
5cd24f17 |
492 | |
66730be0 |
493 | sub log10 { |
494 | my ($z) = @_; |
5cd24f17 |
495 | |
496 | return log(cplx($z, 0)) * log10inv unless ref $z; |
66730be0 |
497 | my ($r, $t) = @{$z->polar}; |
5cd24f17 |
498 | return (ref $z)->make(log($r) * log10inv, $t * log10inv); |
66730be0 |
499 | } |
500 | |
501 | # |
502 | # logn |
503 | # |
504 | # Compute logn(z,n) = log(z) / log(n) |
505 | # |
506 | sub logn { |
507 | my ($z, $n) = @_; |
0c721ce2 |
508 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
509 | my $logn = $logn{$n}; |
510 | $logn = $logn{$n} = log($n) unless defined $logn; # Cache log(n) |
0c721ce2 |
511 | return log($z) / $logn; |
66730be0 |
512 | } |
513 | |
514 | # |
515 | # (cos) |
516 | # |
517 | # Compute cos(z) = (exp(iz) + exp(-iz))/2. |
518 | # |
519 | sub cos { |
520 | my ($z) = @_; |
5cd24f17 |
521 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
522 | my ($x, $y) = @{$z->cartesian}; |
523 | my $ey = exp($y); |
524 | my $ey_1 = 1 / $ey; |
0c721ce2 |
525 | return (ref $z)->make(cos($x) * ($ey + $ey_1)/2, |
526 | sin($x) * ($ey_1 - $ey)/2); |
66730be0 |
527 | } |
528 | |
529 | # |
530 | # (sin) |
531 | # |
532 | # Compute sin(z) = (exp(iz) - exp(-iz))/2. |
533 | # |
534 | sub sin { |
535 | my ($z) = @_; |
5cd24f17 |
536 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
537 | my ($x, $y) = @{$z->cartesian}; |
538 | my $ey = exp($y); |
539 | my $ey_1 = 1 / $ey; |
0c721ce2 |
540 | return (ref $z)->make(sin($x) * ($ey + $ey_1)/2, |
541 | cos($x) * ($ey - $ey_1)/2); |
66730be0 |
542 | } |
543 | |
544 | # |
545 | # tan |
546 | # |
547 | # Compute tan(z) = sin(z) / cos(z). |
548 | # |
549 | sub tan { |
550 | my ($z) = @_; |
0c721ce2 |
551 | my $cz = cos($z); |
552 | divbyzero "tan($z)", "cos($z)" if ($cz == 0); |
553 | return sin($z) / $cz; |
66730be0 |
554 | } |
555 | |
556 | # |
0c721ce2 |
557 | # sec |
558 | # |
559 | # Computes the secant sec(z) = 1 / cos(z). |
560 | # |
561 | sub sec { |
562 | my ($z) = @_; |
563 | my $cz = cos($z); |
564 | divbyzero "sec($z)", "cos($z)" if ($cz == 0); |
565 | return 1 / $cz; |
566 | } |
567 | |
568 | # |
569 | # csc |
570 | # |
571 | # Computes the cosecant csc(z) = 1 / sin(z). |
572 | # |
573 | sub csc { |
574 | my ($z) = @_; |
575 | my $sz = sin($z); |
576 | divbyzero "csc($z)", "sin($z)" if ($sz == 0); |
577 | return 1 / $sz; |
578 | } |
579 | |
66730be0 |
580 | # |
0c721ce2 |
581 | # cosec |
66730be0 |
582 | # |
0c721ce2 |
583 | # Alias for csc(). |
584 | # |
585 | sub cosec { Math::Complex::csc(@_) } |
586 | |
587 | # |
588 | # cot |
589 | # |
590 | # Computes cot(z) = 1 / tan(z). |
591 | # |
592 | sub cot { |
66730be0 |
593 | my ($z) = @_; |
0c721ce2 |
594 | my $sz = sin($z); |
595 | divbyzero "cot($z)", "sin($z)" if ($sz == 0); |
596 | return cos($z) / $sz; |
66730be0 |
597 | } |
598 | |
599 | # |
0c721ce2 |
600 | # cotan |
601 | # |
602 | # Alias for cot(). |
603 | # |
604 | sub cotan { Math::Complex::cot(@_) } |
605 | |
606 | # |
66730be0 |
607 | # acos |
608 | # |
609 | # Computes the arc cosine acos(z) = -i log(z + sqrt(z*z-1)). |
610 | # |
611 | sub acos { |
612 | my ($z) = @_; |
0c721ce2 |
613 | $z = cplx($z, 0) unless ref $z; |
614 | return ~i * log($z + (Re($z) * Im($z) > 0 ? 1 : -1) * sqrt($z*$z - 1)); |
66730be0 |
615 | } |
616 | |
617 | # |
618 | # asin |
619 | # |
620 | # Computes the arc sine asin(z) = -i log(iz + sqrt(1-z*z)). |
621 | # |
622 | sub asin { |
623 | my ($z) = @_; |
0c721ce2 |
624 | $z = cplx($z, 0) unless ref $z; |
625 | return ~i * log(i * $z + sqrt(1 - $z*$z)); |
66730be0 |
626 | } |
627 | |
628 | # |
629 | # atan |
630 | # |
0c721ce2 |
631 | # Computes the arc tangent atan(z) = i/2 log((i+z) / (i-z)). |
66730be0 |
632 | # |
633 | sub atan { |
634 | my ($z) = @_; |
5cd24f17 |
635 | $z = cplx($z, 0) unless ref $z; |
0c721ce2 |
636 | divbyzero "atan($z)", "i - $z" if ($z == i); |
637 | return i/2*log((i + $z) / (i - $z)); |
a0d0e21e |
638 | } |
639 | |
66730be0 |
640 | # |
0c721ce2 |
641 | # asec |
642 | # |
643 | # Computes the arc secant asec(z) = acos(1 / z). |
644 | # |
645 | sub asec { |
646 | my ($z) = @_; |
5cd24f17 |
647 | divbyzero "asec($z)", $z if ($z == 0); |
0c721ce2 |
648 | return acos(1 / $z); |
649 | } |
650 | |
651 | # |
5cd24f17 |
652 | # acsc |
0c721ce2 |
653 | # |
654 | # Computes the arc cosecant sec(z) = asin(1 / z). |
655 | # |
5cd24f17 |
656 | sub acsc { |
0c721ce2 |
657 | my ($z) = @_; |
5cd24f17 |
658 | divbyzero "acsc($z)", $z if ($z == 0); |
0c721ce2 |
659 | return asin(1 / $z); |
660 | } |
661 | |
662 | # |
5cd24f17 |
663 | # acosec |
66730be0 |
664 | # |
5cd24f17 |
665 | # Alias for acsc(). |
0c721ce2 |
666 | # |
5cd24f17 |
667 | sub acosec { Math::Complex::acsc(@_) } |
0c721ce2 |
668 | |
66730be0 |
669 | # |
0c721ce2 |
670 | # acot |
671 | # |
672 | # Computes the arc cotangent acot(z) = -i/2 log((i+z) / (z-i)) |
673 | # |
674 | sub acot { |
66730be0 |
675 | my ($z) = @_; |
5cd24f17 |
676 | $z = cplx($z, 0) unless ref $z; |
0c721ce2 |
677 | divbyzero "acot($z)", "$z - i" if ($z == i); |
66730be0 |
678 | return i/-2 * log((i + $z) / ($z - i)); |
679 | } |
680 | |
681 | # |
0c721ce2 |
682 | # acotan |
683 | # |
684 | # Alias for acot(). |
685 | # |
686 | sub acotan { Math::Complex::acot(@_) } |
687 | |
688 | # |
66730be0 |
689 | # cosh |
690 | # |
691 | # Computes the hyperbolic cosine cosh(z) = (exp(z) + exp(-z))/2. |
692 | # |
693 | sub cosh { |
694 | my ($z) = @_; |
5cd24f17 |
695 | my ($x, $y) = ref $z ? @{$z->cartesian} : ($z, 0); |
66730be0 |
696 | my $ex = exp($x); |
697 | my $ex_1 = 1 / $ex; |
698 | return ($ex + $ex_1)/2 unless ref $z; |
0c721ce2 |
699 | return (ref $z)->make(cos($y) * ($ex + $ex_1)/2, |
700 | sin($y) * ($ex - $ex_1)/2); |
66730be0 |
701 | } |
702 | |
703 | # |
704 | # sinh |
705 | # |
706 | # Computes the hyperbolic sine sinh(z) = (exp(z) - exp(-z))/2. |
707 | # |
708 | sub sinh { |
709 | my ($z) = @_; |
5cd24f17 |
710 | my ($x, $y) = ref $z ? @{$z->cartesian} : ($z, 0); |
66730be0 |
711 | my $ex = exp($x); |
712 | my $ex_1 = 1 / $ex; |
713 | return ($ex - $ex_1)/2 unless ref $z; |
0c721ce2 |
714 | return (ref $z)->make(cos($y) * ($ex - $ex_1)/2, |
715 | sin($y) * ($ex + $ex_1)/2); |
66730be0 |
716 | } |
717 | |
718 | # |
719 | # tanh |
720 | # |
721 | # Computes the hyperbolic tangent tanh(z) = sinh(z) / cosh(z). |
722 | # |
723 | sub tanh { |
724 | my ($z) = @_; |
0c721ce2 |
725 | my $cz = cosh($z); |
726 | divbyzero "tanh($z)", "cosh($z)" if ($cz == 0); |
727 | return sinh($z) / $cz; |
66730be0 |
728 | } |
729 | |
730 | # |
0c721ce2 |
731 | # sech |
732 | # |
733 | # Computes the hyperbolic secant sech(z) = 1 / cosh(z). |
734 | # |
735 | sub sech { |
736 | my ($z) = @_; |
737 | my $cz = cosh($z); |
738 | divbyzero "sech($z)", "cosh($z)" if ($cz == 0); |
739 | return 1 / $cz; |
740 | } |
741 | |
742 | # |
743 | # csch |
744 | # |
745 | # Computes the hyperbolic cosecant csch(z) = 1 / sinh(z). |
66730be0 |
746 | # |
0c721ce2 |
747 | sub csch { |
748 | my ($z) = @_; |
749 | my $sz = sinh($z); |
750 | divbyzero "csch($z)", "sinh($z)" if ($sz == 0); |
751 | return 1 / $sz; |
752 | } |
753 | |
754 | # |
755 | # cosech |
756 | # |
757 | # Alias for csch(). |
758 | # |
759 | sub cosech { Math::Complex::csch(@_) } |
760 | |
66730be0 |
761 | # |
0c721ce2 |
762 | # coth |
763 | # |
764 | # Computes the hyperbolic cotangent coth(z) = cosh(z) / sinh(z). |
765 | # |
766 | sub coth { |
66730be0 |
767 | my ($z) = @_; |
0c721ce2 |
768 | my $sz = sinh($z); |
769 | divbyzero "coth($z)", "sinh($z)" if ($sz == 0); |
770 | return cosh($z) / $sz; |
66730be0 |
771 | } |
772 | |
773 | # |
0c721ce2 |
774 | # cotanh |
775 | # |
776 | # Alias for coth(). |
777 | # |
778 | sub cotanh { Math::Complex::coth(@_) } |
779 | |
780 | # |
66730be0 |
781 | # acosh |
782 | # |
783 | # Computes the arc hyperbolic cosine acosh(z) = log(z + sqrt(z*z-1)). |
784 | # |
785 | sub acosh { |
786 | my ($z) = @_; |
5cd24f17 |
787 | $z = cplx($z, 0) unless ref $z; |
0c721ce2 |
788 | return log($z + sqrt($z*$z - 1)); |
66730be0 |
789 | } |
790 | |
791 | # |
792 | # asinh |
793 | # |
794 | # Computes the arc hyperbolic sine asinh(z) = log(z + sqrt(z*z-1)) |
795 | # |
796 | sub asinh { |
797 | my ($z) = @_; |
5cd24f17 |
798 | $z = cplx($z, 0) unless ref $z; |
0c721ce2 |
799 | return log($z + sqrt($z*$z + 1)); |
66730be0 |
800 | } |
801 | |
802 | # |
803 | # atanh |
804 | # |
805 | # Computes the arc hyperbolic tangent atanh(z) = 1/2 log((1+z) / (1-z)). |
806 | # |
807 | sub atanh { |
808 | my ($z) = @_; |
0c721ce2 |
809 | divbyzero 'atanh(1)', "1 - $z" if ($z == 1); |
5cd24f17 |
810 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
811 | my $cz = (1 + $z) / (1 - $z); |
66730be0 |
812 | return log($cz) / 2; |
813 | } |
814 | |
815 | # |
0c721ce2 |
816 | # asech |
817 | # |
818 | # Computes the hyperbolic arc secant asech(z) = acosh(1 / z). |
819 | # |
820 | sub asech { |
821 | my ($z) = @_; |
822 | divbyzero 'asech(0)', $z if ($z == 0); |
823 | return acosh(1 / $z); |
824 | } |
825 | |
826 | # |
827 | # acsch |
66730be0 |
828 | # |
0c721ce2 |
829 | # Computes the hyperbolic arc cosecant acsch(z) = asinh(1 / z). |
66730be0 |
830 | # |
0c721ce2 |
831 | sub acsch { |
66730be0 |
832 | my ($z) = @_; |
0c721ce2 |
833 | divbyzero 'acsch(0)', $z if ($z == 0); |
834 | return asinh(1 / $z); |
835 | } |
836 | |
837 | # |
838 | # acosech |
839 | # |
840 | # Alias for acosh(). |
841 | # |
842 | sub acosech { Math::Complex::acsch(@_) } |
843 | |
844 | # |
845 | # acoth |
846 | # |
847 | # Computes the arc hyperbolic cotangent acoth(z) = 1/2 log((1+z) / (z-1)). |
848 | # |
849 | sub acoth { |
850 | my ($z) = @_; |
0c721ce2 |
851 | divbyzero 'acoth(1)', "$z - 1" if ($z == 1); |
5cd24f17 |
852 | $z = cplx($z, 0) unless ref $z; |
66730be0 |
853 | my $cz = (1 + $z) / ($z - 1); |
66730be0 |
854 | return log($cz) / 2; |
855 | } |
856 | |
857 | # |
0c721ce2 |
858 | # acotanh |
859 | # |
860 | # Alias for acot(). |
861 | # |
862 | sub acotanh { Math::Complex::acoth(@_) } |
863 | |
864 | # |
66730be0 |
865 | # (atan2) |
866 | # |
867 | # Compute atan(z1/z2). |
868 | # |
869 | sub atan2 { |
870 | my ($z1, $z2, $inverted) = @_; |
5cd24f17 |
871 | my ($re1, $im1) = ref $z1 ? @{$z1->cartesian} : ($z1, 0); |
872 | my ($re2, $im2) = ref $z2 ? @{$z2->cartesian} : ($z2, 0); |
66730be0 |
873 | my $tan; |
874 | if (defined $inverted && $inverted) { # atan(z2/z1) |
875 | return pi * ($re2 > 0 ? 1 : -1) if $re1 == 0 && $im1 == 0; |
876 | $tan = $z2 / $z1; |
877 | } else { |
878 | return pi * ($re1 > 0 ? 1 : -1) if $re2 == 0 && $im2 == 0; |
879 | $tan = $z1 / $z2; |
880 | } |
881 | return atan($tan); |
882 | } |
883 | |
884 | # |
885 | # display_format |
886 | # ->display_format |
887 | # |
888 | # Set (fetch if no argument) display format for all complex numbers that |
889 | # don't happen to have overrriden it via ->display_format |
890 | # |
891 | # When called as a method, this actually sets the display format for |
892 | # the current object. |
893 | # |
894 | # Valid object formats are 'c' and 'p' for cartesian and polar. The first |
895 | # letter is used actually, so the type can be fully spelled out for clarity. |
896 | # |
897 | sub display_format { |
898 | my $self = shift; |
899 | my $format = undef; |
900 | |
901 | if (ref $self) { # Called as a method |
902 | $format = shift; |
0c721ce2 |
903 | } else { # Regular procedure call |
66730be0 |
904 | $format = $self; |
905 | undef $self; |
906 | } |
907 | |
908 | if (defined $self) { |
909 | return defined $self->{display} ? $self->{display} : $display |
910 | unless defined $format; |
911 | return $self->{display} = $format; |
912 | } |
913 | |
914 | return $display unless defined $format; |
915 | return $display = $format; |
916 | } |
917 | |
918 | # |
919 | # (stringify) |
920 | # |
921 | # Show nicely formatted complex number under its cartesian or polar form, |
922 | # depending on the current display format: |
923 | # |
924 | # . If a specific display format has been recorded for this object, use it. |
925 | # . Otherwise, use the generic current default for all complex numbers, |
926 | # which is a package global variable. |
927 | # |
a0d0e21e |
928 | sub stringify { |
66730be0 |
929 | my ($z) = shift; |
930 | my $format; |
931 | |
932 | $format = $display; |
933 | $format = $z->{display} if defined $z->{display}; |
934 | |
935 | return $z->stringify_polar if $format =~ /^p/i; |
936 | return $z->stringify_cartesian; |
937 | } |
938 | |
939 | # |
940 | # ->stringify_cartesian |
941 | # |
942 | # Stringify as a cartesian representation 'a+bi'. |
943 | # |
944 | sub stringify_cartesian { |
945 | my $z = shift; |
946 | my ($x, $y) = @{$z->cartesian}; |
947 | my ($re, $im); |
948 | |
55497cff |
949 | $x = int($x + ($x < 0 ? -1 : 1) * 1e-14) |
950 | if int(abs($x)) != int(abs($x) + 1e-14); |
951 | $y = int($y + ($y < 0 ? -1 : 1) * 1e-14) |
952 | if int(abs($y)) != int(abs($y) + 1e-14); |
953 | |
66730be0 |
954 | $re = "$x" if abs($x) >= 1e-14; |
955 | if ($y == 1) { $im = 'i' } |
956 | elsif ($y == -1) { $im = '-i' } |
40da2db3 |
957 | elsif (abs($y) >= 1e-14) { $im = $y . "i" } |
66730be0 |
958 | |
0c721ce2 |
959 | my $str = ''; |
66730be0 |
960 | $str = $re if defined $re; |
961 | $str .= "+$im" if defined $im; |
962 | $str =~ s/\+-/-/; |
963 | $str =~ s/^\+//; |
964 | $str = '0' unless $str; |
965 | |
966 | return $str; |
967 | } |
968 | |
969 | # |
970 | # ->stringify_polar |
971 | # |
972 | # Stringify as a polar representation '[r,t]'. |
973 | # |
974 | sub stringify_polar { |
975 | my $z = shift; |
976 | my ($r, $t) = @{$z->polar}; |
977 | my $theta; |
0c721ce2 |
978 | my $eps = 1e-14; |
66730be0 |
979 | |
0c721ce2 |
980 | return '[0,0]' if $r <= $eps; |
a0d0e21e |
981 | |
66730be0 |
982 | my $tpi = 2 * pi; |
983 | my $nt = $t / $tpi; |
984 | $nt = ($nt - int($nt)) * $tpi; |
985 | $nt += $tpi if $nt < 0; # Range [0, 2pi] |
a0d0e21e |
986 | |
0c721ce2 |
987 | if (abs($nt) <= $eps) { $theta = 0 } |
988 | elsif (abs(pi-$nt) <= $eps) { $theta = 'pi' } |
66730be0 |
989 | |
55497cff |
990 | if (defined $theta) { |
0c721ce2 |
991 | $r = int($r + ($r < 0 ? -1 : 1) * $eps) |
992 | if int(abs($r)) != int(abs($r) + $eps); |
993 | $theta = int($theta + ($theta < 0 ? -1 : 1) * $eps) |
994 | if ($theta ne 'pi' and |
995 | int(abs($theta)) != int(abs($theta) + $eps)); |
55497cff |
996 | return "\[$r,$theta\]"; |
997 | } |
66730be0 |
998 | |
999 | # |
1000 | # Okay, number is not a real. Try to identify pi/n and friends... |
1001 | # |
1002 | |
1003 | $nt -= $tpi if $nt > pi; |
1004 | my ($n, $k, $kpi); |
1005 | |
1006 | for ($k = 1, $kpi = pi; $k < 10; $k++, $kpi += pi) { |
1007 | $n = int($kpi / $nt + ($nt > 0 ? 1 : -1) * 0.5); |
0c721ce2 |
1008 | if (abs($kpi/$n - $nt) <= $eps) { |
1009 | $theta = ($nt < 0 ? '-':''). |
1010 | ($k == 1 ? 'pi':"${k}pi").'/'.abs($n); |
66730be0 |
1011 | last; |
1012 | } |
1013 | } |
1014 | |
1015 | $theta = $nt unless defined $theta; |
1016 | |
0c721ce2 |
1017 | $r = int($r + ($r < 0 ? -1 : 1) * $eps) |
1018 | if int(abs($r)) != int(abs($r) + $eps); |
1019 | $theta = int($theta + ($theta < 0 ? -1 : 1) * $eps) |
1020 | if ($theta !~ m(^-?\d*pi/\d+$) and |
1021 | int(abs($theta)) != int(abs($theta) + $eps)); |
55497cff |
1022 | |
66730be0 |
1023 | return "\[$r,$theta\]"; |
a0d0e21e |
1024 | } |
a5f75d66 |
1025 | |
1026 | 1; |
1027 | __END__ |
1028 | |
1029 | =head1 NAME |
1030 | |
66730be0 |
1031 | Math::Complex - complex numbers and associated mathematical functions |
a5f75d66 |
1032 | |
1033 | =head1 SYNOPSIS |
1034 | |
66730be0 |
1035 | use Math::Complex; |
5aabfad6 |
1036 | |
66730be0 |
1037 | $z = Math::Complex->make(5, 6); |
1038 | $t = 4 - 3*i + $z; |
1039 | $j = cplxe(1, 2*pi/3); |
a5f75d66 |
1040 | |
1041 | =head1 DESCRIPTION |
1042 | |
66730be0 |
1043 | This package lets you create and manipulate complex numbers. By default, |
1044 | I<Perl> limits itself to real numbers, but an extra C<use> statement brings |
1045 | full complex support, along with a full set of mathematical functions |
1046 | typically associated with and/or extended to complex numbers. |
1047 | |
1048 | If you wonder what complex numbers are, they were invented to be able to solve |
1049 | the following equation: |
1050 | |
1051 | x*x = -1 |
1052 | |
1053 | and by definition, the solution is noted I<i> (engineers use I<j> instead since |
1054 | I<i> usually denotes an intensity, but the name does not matter). The number |
1055 | I<i> is a pure I<imaginary> number. |
1056 | |
1057 | The arithmetics with pure imaginary numbers works just like you would expect |
1058 | it with real numbers... you just have to remember that |
1059 | |
1060 | i*i = -1 |
1061 | |
1062 | so you have: |
1063 | |
1064 | 5i + 7i = i * (5 + 7) = 12i |
1065 | 4i - 3i = i * (4 - 3) = i |
1066 | 4i * 2i = -8 |
1067 | 6i / 2i = 3 |
1068 | 1 / i = -i |
1069 | |
1070 | Complex numbers are numbers that have both a real part and an imaginary |
1071 | part, and are usually noted: |
1072 | |
1073 | a + bi |
1074 | |
1075 | where C<a> is the I<real> part and C<b> is the I<imaginary> part. The |
1076 | arithmetic with complex numbers is straightforward. You have to |
1077 | keep track of the real and the imaginary parts, but otherwise the |
1078 | rules used for real numbers just apply: |
1079 | |
1080 | (4 + 3i) + (5 - 2i) = (4 + 5) + i(3 - 2) = 9 + i |
1081 | (2 + i) * (4 - i) = 2*4 + 4i -2i -i*i = 8 + 2i + 1 = 9 + 2i |
1082 | |
1083 | A graphical representation of complex numbers is possible in a plane |
1084 | (also called the I<complex plane>, but it's really a 2D plane). |
1085 | The number |
1086 | |
1087 | z = a + bi |
1088 | |
1089 | is the point whose coordinates are (a, b). Actually, it would |
1090 | be the vector originating from (0, 0) to (a, b). It follows that the addition |
1091 | of two complex numbers is a vectorial addition. |
1092 | |
1093 | Since there is a bijection between a point in the 2D plane and a complex |
1094 | number (i.e. the mapping is unique and reciprocal), a complex number |
1095 | can also be uniquely identified with polar coordinates: |
1096 | |
1097 | [rho, theta] |
1098 | |
1099 | where C<rho> is the distance to the origin, and C<theta> the angle between |
1100 | the vector and the I<x> axis. There is a notation for this using the |
1101 | exponential form, which is: |
1102 | |
1103 | rho * exp(i * theta) |
1104 | |
1105 | where I<i> is the famous imaginary number introduced above. Conversion |
1106 | between this form and the cartesian form C<a + bi> is immediate: |
1107 | |
1108 | a = rho * cos(theta) |
1109 | b = rho * sin(theta) |
1110 | |
1111 | which is also expressed by this formula: |
1112 | |
1113 | z = rho * exp(i * theta) = rho * (cos theta + i * sin theta) |
1114 | |
1115 | In other words, it's the projection of the vector onto the I<x> and I<y> |
1116 | axes. Mathematicians call I<rho> the I<norm> or I<modulus> and I<theta> |
1117 | the I<argument> of the complex number. The I<norm> of C<z> will be |
1118 | noted C<abs(z)>. |
1119 | |
1120 | The polar notation (also known as the trigonometric |
1121 | representation) is much more handy for performing multiplications and |
1122 | divisions of complex numbers, whilst the cartesian notation is better |
1123 | suited for additions and substractions. Real numbers are on the I<x> |
1124 | axis, and therefore I<theta> is zero. |
1125 | |
1126 | All the common operations that can be performed on a real number have |
1127 | been defined to work on complex numbers as well, and are merely |
1128 | I<extensions> of the operations defined on real numbers. This means |
1129 | they keep their natural meaning when there is no imaginary part, provided |
1130 | the number is within their definition set. |
1131 | |
1132 | For instance, the C<sqrt> routine which computes the square root of |
1133 | its argument is only defined for positive real numbers and yields a |
1134 | positive real number (it is an application from B<R+> to B<R+>). |
1135 | If we allow it to return a complex number, then it can be extended to |
1136 | negative real numbers to become an application from B<R> to B<C> (the |
1137 | set of complex numbers): |
1138 | |
1139 | sqrt(x) = x >= 0 ? sqrt(x) : sqrt(-x)*i |
1140 | |
1141 | It can also be extended to be an application from B<C> to B<C>, |
1142 | whilst its restriction to B<R> behaves as defined above by using |
1143 | the following definition: |
1144 | |
1145 | sqrt(z = [r,t]) = sqrt(r) * exp(i * t/2) |
1146 | |
1147 | Indeed, a negative real number can be noted C<[x,pi]> |
1148 | (the modulus I<x> is always positive, so C<[x,pi]> is really C<-x>, a |
1149 | negative number) |
1150 | and the above definition states that |
1151 | |
1152 | sqrt([x,pi]) = sqrt(x) * exp(i*pi/2) = [sqrt(x),pi/2] = sqrt(x)*i |
1153 | |
1154 | which is exactly what we had defined for negative real numbers above. |
a5f75d66 |
1155 | |
66730be0 |
1156 | All the common mathematical functions defined on real numbers that |
1157 | are extended to complex numbers share that same property of working |
1158 | I<as usual> when the imaginary part is zero (otherwise, it would not |
1159 | be called an extension, would it?). |
a5f75d66 |
1160 | |
66730be0 |
1161 | A I<new> operation possible on a complex number that is |
1162 | the identity for real numbers is called the I<conjugate>, and is noted |
1163 | with an horizontal bar above the number, or C<~z> here. |
a5f75d66 |
1164 | |
66730be0 |
1165 | z = a + bi |
1166 | ~z = a - bi |
a5f75d66 |
1167 | |
66730be0 |
1168 | Simple... Now look: |
a5f75d66 |
1169 | |
66730be0 |
1170 | z * ~z = (a + bi) * (a - bi) = a*a + b*b |
a5f75d66 |
1171 | |
66730be0 |
1172 | We saw that the norm of C<z> was noted C<abs(z)> and was defined as the |
1173 | distance to the origin, also known as: |
a5f75d66 |
1174 | |
66730be0 |
1175 | rho = abs(z) = sqrt(a*a + b*b) |
a5f75d66 |
1176 | |
66730be0 |
1177 | so |
1178 | |
1179 | z * ~z = abs(z) ** 2 |
1180 | |
1181 | If z is a pure real number (i.e. C<b == 0>), then the above yields: |
1182 | |
1183 | a * a = abs(a) ** 2 |
1184 | |
1185 | which is true (C<abs> has the regular meaning for real number, i.e. stands |
1186 | for the absolute value). This example explains why the norm of C<z> is |
1187 | noted C<abs(z)>: it extends the C<abs> function to complex numbers, yet |
1188 | is the regular C<abs> we know when the complex number actually has no |
1189 | imaginary part... This justifies I<a posteriori> our use of the C<abs> |
1190 | notation for the norm. |
1191 | |
1192 | =head1 OPERATIONS |
1193 | |
1194 | Given the following notations: |
1195 | |
1196 | z1 = a + bi = r1 * exp(i * t1) |
1197 | z2 = c + di = r2 * exp(i * t2) |
1198 | z = <any complex or real number> |
1199 | |
1200 | the following (overloaded) operations are supported on complex numbers: |
1201 | |
1202 | z1 + z2 = (a + c) + i(b + d) |
1203 | z1 - z2 = (a - c) + i(b - d) |
1204 | z1 * z2 = (r1 * r2) * exp(i * (t1 + t2)) |
1205 | z1 / z2 = (r1 / r2) * exp(i * (t1 - t2)) |
1206 | z1 ** z2 = exp(z2 * log z1) |
1207 | ~z1 = a - bi |
1208 | abs(z1) = r1 = sqrt(a*a + b*b) |
1209 | sqrt(z1) = sqrt(r1) * exp(i * t1/2) |
1210 | exp(z1) = exp(a) * exp(i * b) |
1211 | log(z1) = log(r1) + i*t1 |
1212 | sin(z1) = 1/2i (exp(i * z1) - exp(-i * z1)) |
1213 | cos(z1) = 1/2 (exp(i * z1) + exp(-i * z1)) |
1214 | abs(z1) = r1 |
1215 | atan2(z1, z2) = atan(z1/z2) |
1216 | |
1217 | The following extra operations are supported on both real and complex |
1218 | numbers: |
1219 | |
1220 | Re(z) = a |
1221 | Im(z) = b |
1222 | arg(z) = t |
1223 | |
1224 | cbrt(z) = z ** (1/3) |
1225 | log10(z) = log(z) / log(10) |
1226 | logn(z, n) = log(z) / log(n) |
1227 | |
1228 | tan(z) = sin(z) / cos(z) |
0c721ce2 |
1229 | |
5aabfad6 |
1230 | csc(z) = 1 / sin(z) |
1231 | sec(z) = 1 / cos(z) |
0c721ce2 |
1232 | cot(z) = 1 / tan(z) |
66730be0 |
1233 | |
1234 | asin(z) = -i * log(i*z + sqrt(1-z*z)) |
1235 | acos(z) = -i * log(z + sqrt(z*z-1)) |
1236 | atan(z) = i/2 * log((i+z) / (i-z)) |
0c721ce2 |
1237 | |
5aabfad6 |
1238 | acsc(z) = asin(1 / z) |
1239 | asec(z) = acos(1 / z) |
0c721ce2 |
1240 | acot(z) = -i/2 * log((i+z) / (z-i)) |
66730be0 |
1241 | |
1242 | sinh(z) = 1/2 (exp(z) - exp(-z)) |
1243 | cosh(z) = 1/2 (exp(z) + exp(-z)) |
0c721ce2 |
1244 | tanh(z) = sinh(z) / cosh(z) = (exp(z) - exp(-z)) / (exp(z) + exp(-z)) |
1245 | |
5aabfad6 |
1246 | csch(z) = 1 / sinh(z) |
1247 | sech(z) = 1 / cosh(z) |
0c721ce2 |
1248 | coth(z) = 1 / tanh(z) |
66730be0 |
1249 | |
1250 | asinh(z) = log(z + sqrt(z*z+1)) |
1251 | acosh(z) = log(z + sqrt(z*z-1)) |
1252 | atanh(z) = 1/2 * log((1+z) / (1-z)) |
66730be0 |
1253 | |
5aabfad6 |
1254 | acsch(z) = asinh(1 / z) |
1255 | asech(z) = acosh(1 / z) |
0c721ce2 |
1256 | acoth(z) = atanh(1 / z) = 1/2 * log((1+z) / (z-1)) |
1257 | |
1258 | I<log>, I<csc>, I<cot>, I<acsc>, I<acot>, I<csch>, I<coth>, |
1259 | I<acosech>, I<acotanh>, have aliases I<ln>, I<cosec>, I<cotan>, |
1260 | I<acosec>, I<acotan>, I<cosech>, I<cotanh>, I<acosech>, I<acotanh>, |
1261 | respectively. |
1262 | |
1263 | The I<root> function is available to compute all the I<n> |
66730be0 |
1264 | roots of some complex, where I<n> is a strictly positive integer. |
1265 | There are exactly I<n> such roots, returned as a list. Getting the |
1266 | number mathematicians call C<j> such that: |
1267 | |
1268 | 1 + j + j*j = 0; |
1269 | |
1270 | is a simple matter of writing: |
1271 | |
1272 | $j = ((root(1, 3))[1]; |
1273 | |
1274 | The I<k>th root for C<z = [r,t]> is given by: |
1275 | |
1276 | (root(z, n))[k] = r**(1/n) * exp(i * (t + 2*k*pi)/n) |
1277 | |
0c721ce2 |
1278 | The I<spaceship> comparison operator is also defined. In order to |
1279 | ensure its restriction to real numbers is conform to what you would |
1280 | expect, the comparison is run on the real part of the complex number |
1281 | first, and imaginary parts are compared only when the real parts |
1282 | match. |
66730be0 |
1283 | |
1284 | =head1 CREATION |
1285 | |
1286 | To create a complex number, use either: |
1287 | |
1288 | $z = Math::Complex->make(3, 4); |
1289 | $z = cplx(3, 4); |
1290 | |
1291 | if you know the cartesian form of the number, or |
1292 | |
1293 | $z = 3 + 4*i; |
1294 | |
1295 | if you like. To create a number using the trigonometric form, use either: |
1296 | |
1297 | $z = Math::Complex->emake(5, pi/3); |
1298 | $x = cplxe(5, pi/3); |
1299 | |
0c721ce2 |
1300 | instead. The first argument is the modulus, the second is the angle |
1301 | (in radians, the full circle is 2*pi). (Mnmemonic: C<e> is used as a |
1302 | notation for complex numbers in the trigonometric form). |
66730be0 |
1303 | |
1304 | It is possible to write: |
1305 | |
1306 | $x = cplxe(-3, pi/4); |
1307 | |
1308 | but that will be silently converted into C<[3,-3pi/4]>, since the modulus |
1309 | must be positive (it represents the distance to the origin in the complex |
1310 | plane). |
1311 | |
1312 | =head1 STRINGIFICATION |
1313 | |
1314 | When printed, a complex number is usually shown under its cartesian |
1315 | form I<a+bi>, but there are legitimate cases where the polar format |
1316 | I<[r,t]> is more appropriate. |
1317 | |
1318 | By calling the routine C<Math::Complex::display_format> and supplying either |
1319 | C<"polar"> or C<"cartesian">, you override the default display format, |
1320 | which is C<"cartesian">. Not supplying any argument returns the current |
1321 | setting. |
1322 | |
1323 | This default can be overridden on a per-number basis by calling the |
1324 | C<display_format> method instead. As before, not supplying any argument |
1325 | returns the current display format for this number. Otherwise whatever you |
1326 | specify will be the new display format for I<this> particular number. |
1327 | |
1328 | For instance: |
1329 | |
1330 | use Math::Complex; |
1331 | |
1332 | Math::Complex::display_format('polar'); |
1333 | $j = ((root(1, 3))[1]; |
1334 | print "j = $j\n"; # Prints "j = [1,2pi/3] |
1335 | $j->display_format('cartesian'); |
1336 | print "j = $j\n"; # Prints "j = -0.5+0.866025403784439i" |
1337 | |
1338 | The polar format attempts to emphasize arguments like I<k*pi/n> |
1339 | (where I<n> is a positive integer and I<k> an integer within [-9,+9]). |
1340 | |
1341 | =head1 USAGE |
1342 | |
1343 | Thanks to overloading, the handling of arithmetics with complex numbers |
1344 | is simple and almost transparent. |
1345 | |
1346 | Here are some examples: |
1347 | |
1348 | use Math::Complex; |
1349 | |
1350 | $j = cplxe(1, 2*pi/3); # $j ** 3 == 1 |
1351 | print "j = $j, j**3 = ", $j ** 3, "\n"; |
1352 | print "1 + j + j**2 = ", 1 + $j + $j**2, "\n"; |
1353 | |
1354 | $z = -16 + 0*i; # Force it to be a complex |
1355 | print "sqrt($z) = ", sqrt($z), "\n"; |
1356 | |
1357 | $k = exp(i * 2*pi/3); |
1358 | print "$j - $k = ", $j - $k, "\n"; |
a5f75d66 |
1359 | |
5cd24f17 |
1360 | =head1 ERRORS DUE TO DIVISION BY ZERO |
5aabfad6 |
1361 | |
1362 | The division (/) and the following functions |
1363 | |
1364 | tan |
1365 | sec |
1366 | csc |
1367 | cot |
5cd24f17 |
1368 | asec |
1369 | acsc |
5aabfad6 |
1370 | atan |
1371 | acot |
1372 | tanh |
1373 | sech |
1374 | csch |
1375 | coth |
1376 | atanh |
1377 | asech |
1378 | acsch |
1379 | acoth |
1380 | |
1381 | cannot be computed for all arguments because that would mean dividing |
1382 | by zero. These situations cause fatal runtime errors looking like this |
1383 | |
1384 | cot(0): Division by zero. |
5cd24f17 |
1385 | (Because in the definition of cot(0), the divisor sin(0) is 0) |
5aabfad6 |
1386 | Died at ... |
1387 | |
5cd24f17 |
1388 | For the C<csc>, C<cot>, C<asec>, C<acsc>, C<csch>, C<coth>, C<asech>, |
1389 | C<acsch>, the argument cannot be C<0> (zero). For the C<atanh>, |
1390 | C<acoth>, the argument cannot be C<1> (one). For the C<atan>, C<acot>, |
1391 | the argument cannot be C<i> (the imaginary unit). For the C<tan>, |
1392 | C<sec>, C<tanh>, C<sech>, the argument cannot be I<pi/2 + k * pi>, where |
1393 | I<k> is any integer. |
1394 | |
a5f75d66 |
1395 | =head1 BUGS |
1396 | |
5cd24f17 |
1397 | Saying C<use Math::Complex;> exports many mathematical routines in the |
1398 | caller environment and even overrides some (C<sin>, C<cos>, C<sqrt>, |
1399 | C<log>, C<exp>). This is construed as a feature by the Authors, |
1400 | actually... ;-) |
66730be0 |
1401 | |
1402 | The code is not optimized for speed, although we try to use the cartesian |
1403 | form for addition-like operators and the trigonometric form for all |
1404 | multiplication-like operators. |
1405 | |
1406 | The arg() routine does not ensure the angle is within the range [-pi,+pi] |
1407 | (a side effect caused by multiplication and division using the trigonometric |
1408 | representation). |
a5f75d66 |
1409 | |
66730be0 |
1410 | All routines expect to be given real or complex numbers. Don't attempt to |
1411 | use BigFloat, since Perl has currently no rule to disambiguate a '+' |
1412 | operation (for instance) between two overloaded entities. |
a5f75d66 |
1413 | |
0c721ce2 |
1414 | =head1 AUTHORS |
a5f75d66 |
1415 | |
0c721ce2 |
1416 | Raphael Manfredi <F<Raphael_Manfredi@grenoble.hp.com>> |
1417 | Jarkko Hietaniemi <F<jhi@iki.fi>> |
5cd24f17 |
1418 | |
1419 | =cut |
1420 | |
1421 | # eof |