Subtract one Legendre series from another. Returns the difference of two Legendre series `c1` - `c2`. The sequences of coefficients are from lowest order term to highest, i.e., [1,2,3] represents the series ``P_0 + 2*P_1 + 3*P_2``. Parameters ---------- c1, c2 : array
(c1, c2)
| 362 | |
| 363 | |
| 364 | def legsub(c1, c2): |
| 365 | """ |
| 366 | Subtract one Legendre series from another. |
| 367 | |
| 368 | Returns the difference of two Legendre series `c1` - `c2`. The |
| 369 | sequences of coefficients are from lowest order term to highest, i.e., |
| 370 | [1,2,3] represents the series ``P_0 + 2*P_1 + 3*P_2``. |
| 371 | |
| 372 | Parameters |
| 373 | ---------- |
| 374 | c1, c2 : array_like |
| 375 | 1-D arrays of Legendre series coefficients ordered from low to |
| 376 | high. |
| 377 | |
| 378 | Returns |
| 379 | ------- |
| 380 | out : ndarray |
| 381 | Of Legendre series coefficients representing their difference. |
| 382 | |
| 383 | See Also |
| 384 | -------- |
| 385 | legadd, legmulx, legmul, legdiv, legpow |
| 386 | |
| 387 | Notes |
| 388 | ----- |
| 389 | Unlike multiplication, division, etc., the difference of two Legendre |
| 390 | series is a Legendre series (without having to "reproject" the result |
| 391 | onto the basis set) so subtraction, just like that of "standard" |
| 392 | polynomials, is simply "component-wise." |
| 393 | |
| 394 | Examples |
| 395 | -------- |
| 396 | >>> from numpy.polynomial import legendre as L |
| 397 | >>> c1 = (1,2,3) |
| 398 | >>> c2 = (3,2,1) |
| 399 | >>> L.legsub(c1,c2) |
| 400 | array([-2., 0., 2.]) |
| 401 | >>> L.legsub(c2,c1) # -C.legsub(c1,c2) |
| 402 | array([ 2., 0., -2.]) |
| 403 | |
| 404 | """ |
| 405 | return pu._sub(c1, c2) |
| 406 | |
| 407 | |
| 408 | def legmulx(c): |