square roots mod p also mupad functionality

Question

Hao Sun 2019-11-5

评论： Walter Roberson 2019-11-5

I've never used mupad before I think but whats with that? like whats the easiet way to take square roots mod p this https://www.mathworks.com/help/symbolic/mupad_ref/numlib-sqrtmodp.html

is no longer working and I can't start up mupad I'm not sure if I'm typing something wrong or if I just don't have that functionality in my license.

John D'Errico 2019-11-5

As I recall, Shanks-Tonelli does it.

Answer 1

Walter Roberson 2019-11-5

evalin(symengine, 'numlib::sqrtmodp(132132,3231227)')

still works, as does using the command

mupad

to start a graphical interface to mupad and then entering

numlib::sqrtmodp(132132,3231227)

there.

Walter Roberson 2019-11-5

feval(symengine, 'numlib::sqrtmodp', sym('132132'), sym('3231227'))

If our values fit within doubles, up to flintmax(), then you do not need the sym() with the quoted number:

feval(symengine, 'numlib::sqrtmodp', 132132, 3231227)