Compute the logarithm base 2 of `x`. Return the "principal value" (for a description of this, see `numpy.log2`) of :math:`log_2(x)`. For real `x > 0`, this is a real number (``log2(0)`` returns ``-inf`` and ``log2(np.inf)`` returns ``inf``). Otherwise, the complex principle val
(x)
| 388 | |
| 389 | @array_function_dispatch(_unary_dispatcher) |
| 390 | def log2(x): |
| 391 | """ |
| 392 | Compute the logarithm base 2 of `x`. |
| 393 | |
| 394 | Return the "principal value" (for a description of this, see |
| 395 | `numpy.log2`) of :math:`log_2(x)`. For real `x > 0`, this is |
| 396 | a real number (``log2(0)`` returns ``-inf`` and ``log2(np.inf)`` returns |
| 397 | ``inf``). Otherwise, the complex principle value is returned. |
| 398 | |
| 399 | Parameters |
| 400 | ---------- |
| 401 | x : array_like |
| 402 | The value(s) whose log base 2 is (are) required. |
| 403 | |
| 404 | Returns |
| 405 | ------- |
| 406 | out : ndarray or scalar |
| 407 | The log base 2 of the `x` value(s). If `x` was a scalar, so is `out`, |
| 408 | otherwise an array is returned. |
| 409 | |
| 410 | See Also |
| 411 | -------- |
| 412 | numpy.log2 |
| 413 | |
| 414 | Notes |
| 415 | ----- |
| 416 | For a log2() that returns ``NAN`` when real `x < 0`, use `numpy.log2` |
| 417 | (note, however, that otherwise `numpy.log2` and this `log2` are |
| 418 | identical, i.e., both return ``-inf`` for `x = 0`, ``inf`` for `x = inf`, |
| 419 | and, notably, the complex principle value if ``x.imag != 0``). |
| 420 | |
| 421 | Examples |
| 422 | -------- |
| 423 | We set the printing precision so the example can be auto-tested: |
| 424 | |
| 425 | >>> np.set_printoptions(precision=4) |
| 426 | |
| 427 | >>> np.emath.log2(8) |
| 428 | 3.0 |
| 429 | >>> np.emath.log2([-4, -8, 8]) |
| 430 | array([2.+4.5324j, 3.+4.5324j, 3.+0.j ]) |
| 431 | |
| 432 | """ |
| 433 | x = _fix_real_lt_zero(x) |
| 434 | return nx.log2(x) |
| 435 | |
| 436 | |
| 437 | def _power_dispatcher(x, p): |
nothing calls this directly
no test coverage detected