Why gives Modulo of complex numbers different answers for rationals and reals

Ask Question

Asked 4 years, 7 months ago

Modified 4 years, 7 months ago

Viewed 54 times

When running

Table[1.*Mod[(1 + I)^(1 + k*I), 1 + k*I], {k, 49, 50, 0.5}]
Table[1.*Mod[(1 + I)^(1 + k*I), 1 + k*I], {k, 49, 50, 1/2}]

I get for the first table

{1.28398*10^-17 - 2.4145*10^-17 I, 1.1351*10^-17 - 1.45645*10^-17 I, 
 9.24544*10^-18 - 8.36557*10^-18 I}

and for the second table completely different values:

{-48. + 50. I, -48.5 + 50.5 I, -49. + 51. I}

In Mathematica 12.0.0.0. Any explanation?

125k11 gold badges407 silver badges581 bronze badges

asked Apr 22, 2020 at 15:49

user57467

2,9307 silver badges13 bronze badges

$\begingroup$ Mod for approximate moduli just gives a result that lies within a disk of the minimal radius based on the modulus. With exact moduli there is a different normalization convention based on Quotient; see the Details and Options section on the reference page. $\endgroup$
– Daniel Lichtblau
Commented Apr 22, 2020 at 22:04
$\begingroup$ What Option settings are you referring to? $\endgroup$
– user57467
Commented Apr 23, 2020 at 0:55
1

$\begingroup$ I made no claim about Option settings. Indeed, Mod takes no options. $\endgroup$
– Daniel Lichtblau
Commented Apr 23, 2020 at 15:27

Add a comment |

0 Your Answer

Name

Required, but never shown

Post as a guest

Name

Required, but never shown

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.