| 1 | // This file is part of SmallBASIC |
| 2 | // |
| 3 | // Math RTL |
| 4 | // |
| 5 | // This program is distributed under the terms of the GPL v2.0 or later |
| 6 | // Download the GNU Public License (GPL) from www.gnu.org |
| 7 | // |
| 8 | // Copyright(C) 2000 Nicholas Christopoulos |
| 9 | |
| 10 | #include "common/sys.h" |
| 11 | #include "common/blib_math.h" |
| 12 | #include "common/kw.h" |
| 13 | #include "common/var.h" |
| 14 | #include "common/device.h" |
| 15 | #include "common/blib.h" |
| 16 | #include "common/pproc.h" |
| 17 | #include "common/smbas.h" |
| 18 | |
| 19 | /* |
| 20 | * INT(x) round downwards to the nearest integer |
| 21 | */ |
| 22 | var_num_t fint(var_num_t x) { |
| 23 | return (x < 0.0) ? -floor(-x) : floor(x); |
| 24 | } |
| 25 | |
| 26 | /* |
| 27 | * FRAC(x) |
| 28 | */ |
| 29 | var_num_t frac(var_num_t x) { |
| 30 | return fabsl(fabsl(x) - fint(fabsl(x))); |
| 31 | } |
| 32 | |
| 33 | /* |
| 34 | * SGN(x) |
| 35 | */ |
| 36 | int sgn(var_num_t x) { |
| 37 | return (x < 0.0) ? -1 : 1; |
| 38 | } |
| 39 | |
| 40 | /* |
| 41 | * ROUND(x, digits) |
| 42 | */ |
| 43 | var_num_t fround(var_num_t x, int dig) { |
| 44 | var_num_t result; |
| 45 | var_num_t m = floor(pow(10.0, dig)); |
| 46 | |
| 47 | if (x < 0.0) { |
| 48 | result = -floor((-x * m) + .5) / m; |
| 49 | } else { |
| 50 | result = floor((x * m) + .5) / m; |
| 51 | } |
| 52 | return result; |
| 53 | } |
| 54 | |
| 55 | void root_iterate(var_num_t xl, var_num_t xh, var_num_t fl, |
| 56 | var_num_t fh, var_t *res_vp, var_num_t maxerr, |
| 57 | var_t *err_vp, bcip_t use_ip); |
| 58 | |
| 59 | /* |
| 60 | * length of line |
| 61 | */ |
| 62 | var_num_t line_length(var_num_t Ax, var_num_t Ay, var_num_t Bx, var_num_t By) { |
| 63 | var_num_t dx, dy; |
| 64 | |
| 65 | dx = Bx - Ax; |
| 66 | dy = By - Ay; |
| 67 | return sqrt(dx * dx + dy * dy); |
| 68 | } |
| 69 | |
| 70 | /* |
| 71 | * Gauss-Jordan method |
| 72 | */ |
| 73 | void mat_gauss_jordan(var_num_t *a, var_num_t *b, int n, double toler) { |
| 74 | var_num_t big, dum, pivinv, swp; |
| 75 | int i, j, k, l, ll; |
| 76 | int icol, irow; |
| 77 | int *indxc, *indxr, *ipiv; |
| 78 | |
| 79 | // |
| 80 | indxc = (int *) malloc(sizeof(int) * n); |
| 81 | indxr = (int *) malloc(sizeof(int) * n); |
| 82 | ipiv = (int *) malloc(sizeof(int) * n); |
| 83 | |
| 84 | // |
| 85 | irow = 0; |
| 86 | icol = 0; |
| 87 | for (j = 0; j < n; j++) { |
| 88 | ipiv[j] = 0; |
| 89 | } |
| 90 | for (i = 0; i < n; i++) { |
| 91 | big = 0.0; |
| 92 | for (j = 0; j < n; j++) { |
| 93 | if (ipiv[j] != 1) { |
| 94 | for (k = 0; k < n; k++) { |
| 95 | if (ipiv[k] == 0) { |
| 96 | if (ABS(a[j * n + k]) >= big) { |
| 97 | big = ABS(a[j * n + k]); |
| 98 | irow = j; |
| 99 | icol = k; |
| 100 | } |
| 101 | } else if (ipiv[k] > 1) { |
| 102 | err_matsig(); |
| 103 | free(indxc); |
| 104 | free(indxr); |
| 105 | free(ipiv); |
| 106 | return; |
| 107 | } |
| 108 | } |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | ipiv[icol] = ipiv[icol] + 1; |
| 113 | if (irow != icol) { |
| 114 | for (l = 0; l < n; l++) { |
| 115 | SWAP(a[irow * n + l], a[icol * n + l], swp); |
| 116 | } |
| 117 | |
| 118 | SWAP(b[irow], b[icol], swp); |
| 119 | } |
| 120 | |
| 121 | indxr[i] = irow; |
| 122 | indxc[i] = icol; |
| 123 | |
| 124 | if (a[icol * n + icol] < toler) { |
| 125 | err_matsig(); |
| 126 | free(indxc); |
| 127 | free(indxr); |
| 128 | free(ipiv); |
| 129 | return; |
| 130 | } |
| 131 | |
| 132 | pivinv = 1.0 / a[icol * n + icol]; |
| 133 | a[icol * n + icol] = 1.0; |
| 134 | for (l = 0; l < n; l++) { |
| 135 | a[icol * n + l] = a[icol * n + l] * pivinv; |
| 136 | } |
| 137 | |
| 138 | b[icol] = b[icol] * pivinv; |
| 139 | for (ll = 0; ll < n; ll++) { |
| 140 | if (ll != icol) { |
| 141 | dum = a[ll * n + icol]; |
| 142 | a[ll * n + icol] = 0.0; |
| 143 | for (l = 0; l < n; l++) { |
| 144 | a[ll * n + l] = a[ll * n + l] - a[icol * n + l] * dum; |
| 145 | } |
| 146 | b[ll] = b[ll] - b[icol] * dum; |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | for (l = n - 1; l >= 0; l--) { |
| 152 | if (indxr[l] != indxc[l]) { |
| 153 | for (k = 0; k < n; k++) { |
| 154 | SWAP(a[k * n + indxr[l]], a[k * n + indxc[l]], swp); |
| 155 | } |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | // /////////////// |
| 160 | free(indxc); |
| 161 | free(indxr); |
| 162 | free(ipiv); |
| 163 | } |
| 164 | |
| 165 | /* |
| 166 | */ |
| 167 | void mat_det2(var_num_t t, int m, int k, var_num_t *a, int *done, var_num_t *v, int n, double toler) { |
| 168 | if (k >= n) { |
| 169 | int s = -1; |
| 170 | |
| 171 | if ((m % 2) == 0) { |
| 172 | s = 1; |
| 173 | } |
| 174 | *v += s * t; |
| 175 | } else { |
| 176 | if (ABS(t) > toler) { |
| 177 | int n2 = 0, j; |
| 178 | |
| 179 | for (j = n - 1; j >= 0; j--) { |
| 180 | if (done[j]) { |
| 181 | n2++; |
| 182 | } else { |
| 183 | done[j] = 1; |
| 184 | mat_det2(t * a[k * n + j], m + n2, k + 1, a, done, v, n, toler); |
| 185 | done[j] = 0; |
| 186 | } |
| 187 | } |
| 188 | } |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * Determinant of A |
| 194 | */ |
| 195 | var_num_t mat_determ(var_num_t *a, int n, double toler) { |
| 196 | int *done; |
| 197 | int i; |
| 198 | var_num_t v; |
| 199 | |
| 200 | done = malloc(n * sizeof(int)); |
| 201 | for (i = 0; i < n; i++) { |
| 202 | done[i] = 0; |
| 203 | } |
| 204 | v = 0; |
| 205 | mat_det2(1, 0, 0, a, done, &v, n, toler); |
| 206 | |
| 207 | free(done); |
| 208 | return v; |
| 209 | } |
| 210 | |
| 211 | /* |
| 212 | */ |
| 213 | var_num_t statmeandev(var_num_t *e, int count) { |
| 214 | var_num_t sum = 0.0; |
| 215 | var_num_t mean; |
| 216 | int i; |
| 217 | |
| 218 | if (count == 0) { |
| 219 | return 0; |
| 220 | } |
| 221 | |
| 222 | for (i = 0; i < count; i++) { |
| 223 | sum += e[i]; |
| 224 | } |
| 225 | mean = sum / count; |
| 226 | |
| 227 | sum = 0.0; |
| 228 | for (i = 0; i < count; i++) { |
| 229 | sum += fabsl(e[i] - mean); |
| 230 | } |
| 231 | |
| 232 | return sum / count; |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | */ |
| 237 | var_num_t statspreads(var_num_t *e, int count) { |
| 238 | var_num_t sumsq = 0.0, sum = 0.0; |
| 239 | int i; |
| 240 | |
| 241 | if (count <= 1) { |
| 242 | return 0; |
| 243 | } |
| 244 | |
| 245 | for (i = 0; i < count; i++) { |
| 246 | sum += e[i]; |
| 247 | sumsq += (e[i] * e[i]); |
| 248 | } |
| 249 | |
| 250 | return sumsq / (count - 1) - (sum * sum) / (count * (count - 1)); |
| 251 | } |
| 252 | |
| 253 | /* |
| 254 | */ |
| 255 | var_num_t statspreadp(var_num_t *e, int count) { |
| 256 | var_num_t sumsq = 0.0, sum = 0.0; |
| 257 | int i; |
| 258 | |
| 259 | if (count <= 0) { |
| 260 | return 0; |
| 261 | } |
| 262 | |
| 263 | for (i = 0; i < count; i++) { |
| 264 | sum += e[i]; |
| 265 | sumsq += (e[i] * e[i]); |
| 266 | } |
| 267 | |
| 268 | return sumsq / count - (sum * sum) / (count * count); |
| 269 | } |
| 270 | |
| 271 | // |
| 272 | // INTEGRAL low, high, maxsegs, maxerr, BYREF result, BYREF err USE f(x) |
| 273 | // |
| 274 | |
| 275 | /* |
| 276 | double simpson(double low, double high, int nseg, bcip_t use_ip) SEC(BMATH2); |
| 277 | double simpson(double low, double high, int nseg, bcip_t use_ip) |
| 278 | { |
| 279 | double width, t, sum, x; |
| 280 | int m, j; |
| 281 | var_t var; |
| 282 | |
| 283 | v_init(&var); |
| 284 | |
| 285 | width = (high - low) / nseg; |
| 286 | |
| 287 | var.type = V_NUM; var.n = low; |
| 288 | exec_usefunc(&var, use_ip); if ( prog_error ) return 0; |
| 289 | sum = v_getval(&var); |
| 290 | v_free(&var); |
| 291 | |
| 292 | var.type = V_NUM; var.n = high; |
| 293 | exec_usefunc(&var, use_ip); if ( prog_error ) return 0; |
| 294 | sum += v_getval(&var); |
| 295 | v_free(&var); |
| 296 | |
| 297 | m = nseg >> 1; |
| 298 | t = 0; |
| 299 | for ( j = 1; j <= m; j ++ ) { |
| 300 | x = low + width * (2 * j - 1); |
| 301 | |
| 302 | var.type = V_NUM; var.n = x; |
| 303 | exec_usefunc(&var, use_ip); if ( prog_error ) return 0; |
| 304 | t += v_getval(&var); |
| 305 | v_free(&var); |
| 306 | } |
| 307 | sum += 4.0 * t; |
| 308 | |
| 309 | m --; |
| 310 | t = 0; |
| 311 | for ( j = 1; j <= m; j ++ ) { |
| 312 | x = low + width * 2.0 * ((double) j); |
| 313 | |
| 314 | var.type = V_NUM; var.n = x; |
| 315 | exec_usefunc(&var, use_ip); if ( prog_error ) return 0; |
| 316 | t += v_getval(&var); |
| 317 | v_free(&var); |
| 318 | } |
| 319 | |
| 320 | sum += 2.0 * t; |
| 321 | return width * sum / 3.0; |
| 322 | } |
| 323 | |
| 324 | void cmd_integral() |
| 325 | { |
| 326 | var_t *res_vp, *err_vp; |
| 327 | double low, high, maxerr, errval, oldval; |
| 328 | int maxseg, nseg; |
| 329 | bcip_t use_ip, exit_ip = INVALID_ADDR; |
| 330 | |
| 331 | low = par_getnum(); if ( prog_error ) return; |
| 332 | par_getcomma(); if ( prog_error ) return; |
| 333 | high = par_getnum(); if ( prog_error ) return; |
| 334 | par_getcomma(); if ( prog_error ) return; |
| 335 | maxseg = par_getint(); if ( prog_error ) return; |
| 336 | par_getcomma(); if ( prog_error ) return; |
| 337 | maxerr = par_getnum(); if ( prog_error ) return; |
| 338 | par_getcomma(); if ( prog_error ) return; |
| 339 | res_vp = par_getvar_ptr(); if ( prog_error ) return; |
| 340 | par_getcomma(); if ( prog_error ) return; |
| 341 | err_vp = par_getvar_ptr(); if ( prog_error ) return; |
| 342 | |
| 343 | if ( code_peek() != kwUSE ) { |
| 344 | rt_raise("INTEGRAL: FUNCTION IS MISSING!"); |
| 345 | return; |
| 346 | } |
| 347 | |
| 348 | // USE |
| 349 | code_skipnext(); |
| 350 | use_ip = code_getaddr(); |
| 351 | exit_ip = code_getaddr(); |
| 352 | |
| 353 | // |
| 354 | v_free(res_vp); |
| 355 | v_free(err_vp); |
| 356 | res_vp->type = V_NUM; res_vp->n = 0; |
| 357 | err_vp->type = V_NUM; err_vp->n = 0; |
| 358 | |
| 359 | nseg = 10; |
| 360 | oldval = simpson(low, high, nseg, use_ip); |
| 361 | if ( !prog_error ) { |
| 362 | do { |
| 363 | nseg = nseg << 1; |
| 364 | res_vp->n = simpson(low, high, nseg, use_ip); |
| 365 | if ( prog_error ) break; |
| 366 | |
| 367 | if ( res_vp->n == 0 ) |
| 368 | errval = 0; |
| 369 | else |
| 370 | errval = ABS((res_vp->n - oldval) / res_vp->n); |
| 371 | if ( nseg > maxseg ) |
| 372 | err_vp->n = -errval; |
| 373 | if ( errval < maxerr ) |
| 374 | err_vp->n = nseg; |
| 375 | oldval = res_vp->n; |
| 376 | } while ( err_vp->n == 0.0 ); |
| 377 | } |
| 378 | |
| 379 | code_jump(exit_ip); |
| 380 | } |
| 381 | */ |
| 382 | |
| 383 | // |
| 384 | // ROOT low, high, maxseg, maxerr, BYREF result, BYREF errcode USE ... |
| 385 | // |
| 386 | void root_iterate(var_num_t xl, var_num_t xh, var_num_t fl, var_num_t fh, var_t *res_vp, var_num_t maxerr, |
| 387 | var_t *err_vp, bcip_t use_ip) { |
| 388 | var_num_t t, x; |
| 389 | var_t var; |
| 390 | |
| 391 | v_init(&var); |
| 392 | do { |
| 393 | x = (xl + xh) / 2.0; |
| 394 | |
| 395 | var.type = V_NUM; |
| 396 | var.v.n = x; |
| 397 | exec_usefunc(&var, use_ip); |
| 398 | if (prog_error) { |
| 399 | return; |
| 400 | } |
| 401 | t = v_getval(&var); |
| 402 | v_free(&var); |
| 403 | |
| 404 | if (ABS(t) < maxerr) { |
| 405 | res_vp->v.n = x; |
| 406 | err_vp->v.i = 0; |
| 407 | return; |
| 408 | } else { |
| 409 | if (t * fl > 0.0) { |
| 410 | (xl = x, fl = t); |
| 411 | } else { |
| 412 | (xh = x, fh = t); |
| 413 | } |
| 414 | } |
| 415 | } while (err_vp->v.i); |
| 416 | } |
| 417 | |
| 418 | void cmd_root() { |
| 419 | var_t *res_vp, *err_vp; |
| 420 | var_num_t low, high, maxerr; |
| 421 | int maxseg, nseg; |
| 422 | bcip_t use_ip, exit_ip = INVALID_ADDR; |
| 423 | var_t var; |
| 424 | |
| 425 | int j; |
| 426 | var_num_t xl, xh, fl, fh, x, width; |
| 427 | |
| 428 | v_init(&var); |
| 429 | low = par_getnum(); |
| 430 | if (prog_error) |
| 431 | return; |
| 432 | par_getcomma(); |
| 433 | if (prog_error) |
| 434 | return; |
| 435 | high = par_getnum(); |
| 436 | if (prog_error) |
| 437 | return; |
| 438 | par_getcomma(); |
| 439 | if (prog_error) |
| 440 | return; |
| 441 | maxseg = par_getint(); |
| 442 | if (prog_error) |
| 443 | return; |
| 444 | par_getcomma(); |
| 445 | if (prog_error) |
| 446 | return; |
| 447 | maxerr = par_getnum(); |
| 448 | if (prog_error) |
| 449 | return; |
| 450 | par_getcomma(); |
| 451 | if (prog_error) |
| 452 | return; |
| 453 | res_vp = par_getvar_ptr(); |
| 454 | if (prog_error) |
| 455 | return; |
| 456 | par_getcomma(); |
| 457 | if (prog_error) |
| 458 | return; |
| 459 | err_vp = par_getvar_ptr(); |
| 460 | if (prog_error) |
| 461 | return; |
| 462 | |
| 463 | if (code_peek() != kwUSE) { |
| 464 | rt_raise("INTEGRAL: FUNCTION IS MISSING!" ); |
| 465 | return; |
| 466 | } |
| 467 | |
| 468 | // USE |
| 469 | code_skipnext(); |
| 470 | use_ip = code_getaddr(); |
| 471 | exit_ip = code_getaddr(); |
| 472 | |
| 473 | // |
| 474 | v_free(res_vp); |
| 475 | v_free(err_vp); |
| 476 | res_vp->type = V_NUM; |
| 477 | res_vp->v.n = 0; |
| 478 | err_vp->type = V_INT; |
| 479 | err_vp->v.i = 1; |
| 480 | |
| 481 | xl = low; |
| 482 | xh = high; |
| 483 | |
| 484 | var.type = V_NUM; |
| 485 | var.v.n = xl; |
| 486 | exec_usefunc(&var, use_ip); |
| 487 | if (prog_error) |
| 488 | return; |
| 489 | fl = v_getval(&var); |
| 490 | v_free(&var); |
| 491 | |
| 492 | var.type = V_NUM; |
| 493 | var.v.n = xh; |
| 494 | exec_usefunc(&var, use_ip); |
| 495 | if (prog_error) |
| 496 | return; |
| 497 | fh = v_getval(&var); |
| 498 | v_free(&var); |
| 499 | |
| 500 | if (ABS(fl) < maxerr) { |
| 501 | err_vp->v.i = 0; |
| 502 | res_vp->v.n = xl; |
| 503 | code_jump(exit_ip); |
| 504 | return; |
| 505 | } |
| 506 | |
| 507 | if (ABS(fh) < maxerr) { |
| 508 | err_vp->v.i = 0; |
| 509 | res_vp->v.n = xh; |
| 510 | code_jump(exit_ip); |
| 511 | return; |
| 512 | } |
| 513 | |
| 514 | if (fl * fh < 0) { |
| 515 | root_iterate(xl, xh, fl, fh, res_vp, maxerr, err_vp, use_ip); |
| 516 | code_jump(exit_ip); |
| 517 | return; |
| 518 | } |
| 519 | |
| 520 | nseg = 2; |
| 521 | do { |
| 522 | width = (xh - xl) / nseg; |
| 523 | for (j = 1; j <= (nseg >> 1); j++) { |
| 524 | x = xl + width * (2 * j - 1); |
| 525 | |
| 526 | var.type = V_NUM; |
| 527 | var.v.n = x; |
| 528 | exec_usefunc(&var, use_ip); |
| 529 | if (prog_error) |
| 530 | return; |
| 531 | fh = v_getval(&var); |
| 532 | v_free(&var); |
| 533 | |
| 534 | if (fh * fl < 0) { |
| 535 | xh = x; |
| 536 | root_iterate(xl, xh, fl, fh, res_vp, maxerr, err_vp, use_ip); |
| 537 | code_jump(exit_ip); |
| 538 | return; |
| 539 | } |
| 540 | } |
| 541 | nseg = nseg << 1; |
| 542 | } while (nseg <= maxseg); |
| 543 | |
| 544 | code_jump(exit_ip); |
| 545 | } |
| 546 | |
| 547 | // |
| 548 | // DERIV x, maxtries, maxerr, BYREF result, BYREF errcode USE ... |
| 549 | // |
| 550 | void cmd_deriv() { |
| 551 | var_t *res_vp, *err_vp; |
| 552 | double maxerr, x; |
| 553 | int maxseg, nseg; |
| 554 | bcip_t use_ip, exit_ip = INVALID_ADDR; |
| 555 | var_t var; |
| 556 | |
| 557 | double delta = 0.01, f1, f2, f3, fp, op = 0.0, errval; |
| 558 | |
| 559 | v_init(&var); |
| 560 | x = par_getnum(); |
| 561 | if (prog_error) |
| 562 | return; |
| 563 | par_getcomma(); |
| 564 | if (prog_error) |
| 565 | return; |
| 566 | maxseg = par_getint(); |
| 567 | if (prog_error) |
| 568 | return; |
| 569 | par_getcomma(); |
| 570 | if (prog_error) |
| 571 | return; |
| 572 | maxerr = par_getnum(); |
| 573 | if (prog_error) |
| 574 | return; |
| 575 | par_getcomma(); |
| 576 | if (prog_error) |
| 577 | return; |
| 578 | res_vp = par_getvar_ptr(); |
| 579 | if (prog_error) |
| 580 | return; |
| 581 | par_getcomma(); |
| 582 | if (prog_error) |
| 583 | return; |
| 584 | err_vp = par_getvar_ptr(); |
| 585 | if (prog_error) |
| 586 | return; |
| 587 | |
| 588 | if (code_peek() != kwUSE) { |
| 589 | rt_raise("INTEGRAL: FUNCTION IS MISSING!" ); |
| 590 | return; |
| 591 | } |
| 592 | |
| 593 | // USE |
| 594 | code_skipnext(); |
| 595 | use_ip = code_getaddr(); |
| 596 | exit_ip = code_getaddr(); |
| 597 | |
| 598 | // |
| 599 | v_free(res_vp); |
| 600 | v_free(err_vp); |
| 601 | res_vp->type = V_NUM; |
| 602 | res_vp->v.n = 0; |
| 603 | err_vp->type = V_INT; |
| 604 | err_vp->v.i = 1; |
| 605 | |
| 606 | nseg = 0; |
| 607 | do { |
| 608 | var.type = V_NUM; |
| 609 | var.v.n = x; |
| 610 | exec_usefunc(&var, use_ip); |
| 611 | if (prog_error) |
| 612 | return; |
| 613 | f1 = v_getval(&var); |
| 614 | v_free(&var); |
| 615 | |
| 616 | var.type = V_NUM; |
| 617 | var.v.n = x + delta; |
| 618 | exec_usefunc(&var, use_ip); |
| 619 | if (prog_error) |
| 620 | return; |
| 621 | f2 = v_getval(&var); |
| 622 | v_free(&var); |
| 623 | |
| 624 | var.type = V_NUM; |
| 625 | var.v.n = x + 2 * delta; |
| 626 | exec_usefunc(&var, use_ip); |
| 627 | if (prog_error) |
| 628 | return; |
| 629 | f3 = v_getval(&var); |
| 630 | v_free(&var); |
| 631 | |
| 632 | fp = (-3.0 * f1 + 4.0 * f2 - f3) / 2.0 / delta; |
| 633 | if (fp == 0.0) |
| 634 | errval = 0; |
| 635 | else |
| 636 | errval = ABS((fp - op) / fp); |
| 637 | |
| 638 | nseg++; |
| 639 | if (nseg >= maxseg) { |
| 640 | res_vp->v.n = fp; |
| 641 | break; |
| 642 | } |
| 643 | |
| 644 | if (errval < maxerr) { |
| 645 | res_vp->v.n = fp; |
| 646 | err_vp->v.i = 0; |
| 647 | } |
| 648 | |
| 649 | delta = delta / 2.0; |
| 650 | op = fp; |
| 651 | |
| 652 | } while (err_vp->v.i); |
| 653 | |
| 654 | code_jump(exit_ip); |
| 655 | } |
| 656 | |
| 657 | // |
| 658 | // DIFFEQ x0, y0, x, maxseg, maxerr, BYREF y, BYREF errcode USE ... |
| 659 | // |
| 660 | void cmd_diffeq() { |
| 661 | var_t *res_vp, *err_vp; |
| 662 | double maxerr; |
| 663 | int maxseg, nseg, j; |
| 664 | bcip_t use_ip, exit_ip = INVALID_ADDR; |
| 665 | var_t var, var2; |
| 666 | |
| 667 | double x0, x1, y0, width, hw, ka, kb, kc, kd, xi, yi; |
| 668 | double errval, yp = 0; |
| 669 | |
| 670 | v_init(&var); |
| 671 | v_init(&var2); |
| 672 | x0 = par_getnum(); |
| 673 | if (prog_error) |
| 674 | return; |
| 675 | par_getcomma(); |
| 676 | if (prog_error) |
| 677 | return; |
| 678 | y0 = par_getnum(); |
| 679 | if (prog_error) |
| 680 | return; |
| 681 | par_getcomma(); |
| 682 | if (prog_error) |
| 683 | return; |
| 684 | x1 = par_getnum(); |
| 685 | if (prog_error) |
| 686 | return; |
| 687 | par_getcomma(); |
| 688 | if (prog_error) |
| 689 | return; |
| 690 | maxseg = par_getint(); |
| 691 | if (prog_error) |
| 692 | return; |
| 693 | par_getcomma(); |
| 694 | if (prog_error) |
| 695 | return; |
| 696 | maxerr = par_getnum(); |
| 697 | if (prog_error) |
| 698 | return; |
| 699 | par_getcomma(); |
| 700 | if (prog_error) |
| 701 | return; |
| 702 | res_vp = par_getvar_ptr(); |
| 703 | if (prog_error) |
| 704 | return; |
| 705 | par_getcomma(); |
| 706 | if (prog_error) |
| 707 | return; |
| 708 | err_vp = par_getvar_ptr(); |
| 709 | if (prog_error) |
| 710 | return; |
| 711 | |
| 712 | if (code_peek() != kwUSE) { |
| 713 | rt_raise("INTEGRAL: FUNCTION IS MISSING!" ); |
| 714 | return; |
| 715 | } |
| 716 | |
| 717 | // USE |
| 718 | code_skipnext(); |
| 719 | use_ip = code_getaddr(); |
| 720 | exit_ip = code_getaddr(); |
| 721 | |
| 722 | // |
| 723 | v_free(res_vp); |
| 724 | v_free(err_vp); |
| 725 | res_vp->type = V_NUM; |
| 726 | res_vp->v.n = 0; |
| 727 | err_vp->type = V_INT; |
| 728 | err_vp->v.i = 1; |
| 729 | |
| 730 | nseg = 1; |
| 731 | do { |
| 732 | width = (x1 - x0) / nseg; |
| 733 | hw = width / 2.0; |
| 734 | |
| 735 | for (j = 1; j <= nseg; j++) { |
| 736 | xi = x0 + (j - 1) * width; |
| 737 | // xf = xi + width; |
| 738 | if (j == 1) |
| 739 | yi = y0; |
| 740 | else |
| 741 | yi = res_vp->v.n; |
| 742 | |
| 743 | var.type = V_NUM; |
| 744 | var.v.n = xi; |
| 745 | var2.type = V_NUM; |
| 746 | var2.v.n = yi; |
| 747 | exec_usefunc2(&var, &var2, use_ip); |
| 748 | if (prog_error) |
| 749 | return; |
| 750 | ka = v_getval(&var); |
| 751 | v_free(&var); |
| 752 | |
| 753 | var.type = V_NUM; |
| 754 | var.v.n = xi + hw; |
| 755 | var2.type = V_NUM; |
| 756 | var2.v.n = yi + ka * hw; |
| 757 | exec_usefunc2(&var, &var2, use_ip); |
| 758 | if (prog_error) |
| 759 | return; |
| 760 | kb = v_getval(&var); |
| 761 | v_free(&var); |
| 762 | |
| 763 | var.type = V_NUM; |
| 764 | var.v.n = xi + hw; |
| 765 | var2.type = V_NUM; |
| 766 | var2.v.n = yi + kb * hw; |
| 767 | exec_usefunc2(&var, &var2, use_ip); |
| 768 | if (prog_error) |
| 769 | return; |
| 770 | kc = v_getval(&var); |
| 771 | v_free(&var); |
| 772 | |
| 773 | var.type = V_NUM; |
| 774 | var.v.n = xi + width; |
| 775 | var2.type = V_NUM; |
| 776 | var2.v.n = yi + kc * width; |
| 777 | exec_usefunc2(&var, &var2, use_ip); |
| 778 | if (prog_error) |
| 779 | return; |
| 780 | kd = v_getval(&var); |
| 781 | v_free(&var); |
| 782 | |
| 783 | res_vp->v.n = yi + width * (ka + 2.0 * kb + 2.0 * kc + kd) / 6.0; |
| 784 | } |
| 785 | |
| 786 | if (nseg == 1) |
| 787 | errval = maxerr; |
| 788 | else { |
| 789 | if (res_vp->v.n == 0) |
| 790 | errval = 0; |
| 791 | else |
| 792 | errval = ABS((res_vp->v.n - yp) / res_vp->v.n); |
| 793 | } |
| 794 | |
| 795 | if (nseg > maxseg) |
| 796 | break; |
| 797 | |
| 798 | if (errval < maxerr || width == 0) { |
| 799 | err_vp->v.i = 0; |
| 800 | break; |
| 801 | } |
| 802 | |
| 803 | yp = res_vp->v.n; |
| 804 | nseg = nseg << 1; |
| 805 | } while (err_vp->v.i); |
| 806 | |
| 807 | code_jump(exit_ip); |
| 808 | } |
| 809 | |