Why do they act differently with respect to complex numbers?
Python 2.2.2 (#1, Feb 24 2003, 19:13:11)
[GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-4)] on linux2
Type "help", "copyright" , "credits" or "license" for more information. pow(2, 0+1j)
(0.769238901363 97211+0.6389612 7631363475j) import math math.pow(2, 0+1j)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: can't convert complex to float; use e.g. abs(z)
Apart from handling complex numbers, the built-in pow also has a
modulo efficiency hack.
When would I want to use math.pow? 5 2708
Clueless Moron <Bi********@Mic rosoft.com> writes: Why do they act differently with respect to complex numbers?
[...] Apart from handling complex numbers, the built-in pow also has a modulo efficiency hack.
When would I want to use math.pow?
For some applications, getting a complex result means you've made a
mistake. And some people don't know what a complex number is, and
would rather have their teeth drilled than find out.
John
You wouldn't know a subtle plan if it painted itself purple and danced
naked on top of a harpsichord singing 'Subtle Plans Are Here Again'
Blackadder
John J. Lee wrote: For some applications, getting a complex result means you've made a mistake. And some people don't know what a complex number is, and would rather have their teeth drilled than find out.
Perhaps, but why should pow() be different from math.pow() in python?
"John J. Lee" <jj*@pobox.co m> wrote in message news:87******** ****@pobox.com. ..
| For some applications, getting a complex result means you've made a
| mistake. And some people don't know what a complex number is, and
| would rather have their teeth drilled than find out.
Can you provide an example when pow with real arguments gives a complex result,
please?
Georgy
|
|
| John
|
| You wouldn't know a subtle plan if it painted itself purple and danced
| naked on top of a harpsichord singing 'Subtle Plans Are Here Again'
|
| Blackadder
Georgy Pruss wrote: "John J. Lee" <jj*@pobox.co m> wrote in message news:87******** ****@pobox.com. .. | For some applications, getting a complex result means you've made a | mistake. And some people don't know what a complex number is, and | would rather have their teeth drilled than find out.
Can you provide an example when pow with real arguments gives a complex result, please?
He could, if Python were not so reluctant: pow(-5,.5)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ValueError: negative number cannot be raised to a fractional power
Sad day for the dentist:-)
But:
pow(complex(-5), .5)
(1.369151526412 4976e-16+2.2360679774 997898j)
pow(-5, complex(.5))
(1.369151526412 4976e-16+2.2360679774 997898j)
as you might expect.
Peter
"Georgy Pruss" <se************ *@hotmail.com> writes: "John J. Lee" <jj*@pobox.co m> wrote in message news:87******** ****@pobox.com. .. | For some applications, getting a complex result means you've made a | mistake. And some people don't know what a complex number is, and | would rather have their teeth drilled than find out.
Can you provide an example when pow with real arguments gives a complex result, please?
[...]
I was thinking about results of earlier calculations providing the
argument for pow.
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