Probably good to think first what the inverse function, np.frexp, should do for complex numbers. I guess the choices are: 1. Remove the largest exponent of real/imaginary, and give a complex mantissa, in which only one of the real or imaginary components is guaranteed to have its absolute value be in the interval [0.5, 1) (but for both the claim in the np.frexp docstring that they are in the interval (-1, 1) would continue to hold). 2. Do real, imaginary separately. 3. Insists on 0.5 < |z| < 1.
The first option seems the most sensible, in which case the suggested extension for ldexp makes sense. -- Marten "Carlos Martin" <cgmar...@andrew.cmu.edu> writes: > Currently, > [ldexp](https://numpy.org/doc/stable/reference/generated/numpy.ldexp.html) > throws a TypeError on a complex input: > > ```python3 > import numpy as np > > def naive_ldexp(x, n): > return x * 2**n > > def new_ldexp(x, n): > if np.iscomplex(x): > y = np.empty_like(x) > y.real = np.ldexp(x.real, n) > y.imag = np.ldexp(x.imag, n) > return y > else: > return np.ldexp(x, n) > > def main(): > x = 2.2 + 3.3j > n = 3 > > print(naive_ldexp(x, n)) > print(new_ldexp(x, n)) > print(np.ldexp(x, n)) > > if __name__ == "__main__": > main() > ``` > > ``` > (17.6+26.4j) > (17.6+26.4j) > Traceback (most recent call last): > File "test.py", line 34, in <module> > main() > File "test.py", line 30, in main > print(np.ldexp(x, n)) > ^^^^^^^^^^^^^^ > TypeError: ufunc 'ldexp' not supported for the input types, and the inputs > could not be safely coerced to any supported types according to the casting > rule ''safe'' > ``` > > This can easily be solved by applying ldexp to the real and imaginary parts > of the input, as shown in the function new_ldexp above. > _______________________________________________ > NumPy-Discussion mailing list -- numpy-discussion@python.org > To unsubscribe send an email to numpy-discussion-le...@python.org > https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ > Member address: m...@astro.utoronto.ca _______________________________________________ NumPy-Discussion mailing list -- numpy-discussion@python.org To unsubscribe send an email to numpy-discussion-le...@python.org https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ Member address: arch...@mail-archive.com
