Compute the inverse cosine of x. Return the "principal value" (for a description of this, see `numpy.arccos`) of the inverse cosine of `x`. For real `x` such that `abs(x) <= 1`, this is a real number in the closed interval :math:`[0, \\pi]`. Otherwise, the complex principle va
(x)
| 485 | |
| 486 | @array_function_dispatch(_unary_dispatcher) |
| 487 | def arccos(x): |
| 488 | """ |
| 489 | Compute the inverse cosine of x. |
| 490 | |
| 491 | Return the "principal value" (for a description of this, see |
| 492 | `numpy.arccos`) of the inverse cosine of `x`. For real `x` such that |
| 493 | `abs(x) <= 1`, this is a real number in the closed interval |
| 494 | :math:`[0, \\pi]`. Otherwise, the complex principle value is returned. |
| 495 | |
| 496 | Parameters |
| 497 | ---------- |
| 498 | x : array_like or scalar |
| 499 | The value(s) whose arccos is (are) required. |
| 500 | |
| 501 | Returns |
| 502 | ------- |
| 503 | out : ndarray or scalar |
| 504 | The inverse cosine(s) of the `x` value(s). If `x` was a scalar, so |
| 505 | is `out`, otherwise an array object is returned. |
| 506 | |
| 507 | See Also |
| 508 | -------- |
| 509 | numpy.arccos |
| 510 | |
| 511 | Notes |
| 512 | ----- |
| 513 | For an arccos() that returns ``NAN`` when real `x` is not in the |
| 514 | interval ``[-1,1]``, use `numpy.arccos`. |
| 515 | |
| 516 | Examples |
| 517 | -------- |
| 518 | >>> np.set_printoptions(precision=4) |
| 519 | |
| 520 | >>> np.emath.arccos(1) # a scalar is returned |
| 521 | 0.0 |
| 522 | |
| 523 | >>> np.emath.arccos([1,2]) |
| 524 | array([0.-0.j , 0.-1.317j]) |
| 525 | |
| 526 | """ |
| 527 | x = _fix_real_abs_gt_1(x) |
| 528 | return nx.arccos(x) |
| 529 | |
| 530 | |
| 531 | @array_function_dispatch(_unary_dispatcher) |