Why does my compiler say invalid syntax then highlight...?

[Mensanator]

On Mar 11, 9:50 pm, Nathan Pinno <MadComputer... at gmail.com> wrote:
> On Mar 11, 1:12 pm, Mensanator <mensana... at aol.com> wrote:
>
>
>
>
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> > On Mar 11, 3:36 am, Duncan Booth <duncan.bo... at invalid.invalid> wrote:
>
> > > Mensanator <mensana... at aol.com> wrote:
> > > > On Mar 10, 10:44‹¨«pm, Nathan Pinno <MadComputer... at gmail.com> wrote:
> > > >> Why does my compiler say invalid syntax and then highlight the
> > > >> quotation marks in the following code:
>
> > > >> # This program is to find primes.
>
> > > > Needs work.
>
> > > Be fair.
>
> > Being helpful isn't fair?
>
> > > The OP hadn't managed to figure out why the program wasn't
> > > running, so you can't expect him to have got all the bugs out of the code
> > > yet.
>
> > The bug had already been answered.
>
> > If you fail to implement your premise correctly, you have a bug.
>
> > It doesn't matter if the code is bug-free if the premise is false.
>
> > In this case, the premise that he can determine primes this way
> > is false. He will have to abandon the cos() thing, for although it
> > works in theory, he'll never get it to work in practice.
>
> > Besides, the cos() is a red herring (hint: cos(pi*n)). The problem
> > can be made to work EXACTLY (at least up to z=10000) by using
> > rationals
> > (which gmpy supports).
>
> > His problem is going to take much more than fixing a syntax error.
>
> > > And he only asked about the specific syntax error not the entire
> > > solution to his homework.
>
> > If this is indeed homework, and he's supposed to come up with a
> > factorial algorithm, I seriously doubt the teacher would accept
> > gmpy.fac(z-1), so I assume it isn't.
>
> > > My advice to Nathan would be:
>
> > > 1. If you get a weird syntax error that you don't understand try cutting
> > > the code down to just the bit which generates the error.
>
> > > 2. Play around in the interactive interpreter to see what works and what
> > > doesn't.
>
> > > 3. If you don't understand why the code doesn't work then get a stuffed
> > > toy, cardboard cutout of a person, or the least technical member of your
> > > family and explain to them in great detail exactly why the code must
> > > (despite error messages to the contrary) be correct. Usually you'll spot
> > > the problem half way through the explanation.
>
> > > 4. If you post to this list then post the full error message and traceback.
> > > That way we don't have to guess which quotation marks are the problem.
>
> Yep, got it fixed, and no, it is not a homework problem...just a
> project for fun to keep up my Python coding in my memory intact
> (apparently, it doesn't work as well when I've been up early 3 days in
> a row... :P ).
>
> Now I just have to figure out why it isn't working the way it is
> supposed to.

Did you see my hints, or are you keen to work it out?

My solution tested up to z=10000. Factorial starts
getting sluggish there and is utterly intractable
for really large numbers, such as RSA.

> It was given to me by someone in the sci.math area as an
> alternative to working with 1 < x < n.- Hide quoted text -
>
> - Show quoted text -