Riemann Siegel Theta Equation

Hey all,

I wanted to know how I would solve an equation involving the Riemann Siegel theta function (https://en.wikipedia.org/wiki/Riemann%E2%80%93Siegel_theta_function). There is a post discussing its implementation in MATLAB here: (https://www.mathworks.com/matlabcentral/answers/539611-how-to-realize-riemann-siegel-theta-function-with-matlab) but my problem is that this implementation does not work if I tried to use vpasolve for an equation like where is our Riemann Siegel theta function and C is some aribtrary real number. I think there is an error involving using symbolic variables inside a double but I am unsure of how to resolve this.

Any advice would be appreciated!

Answer 1

[Paul]

Hi bil,

Is this what you're looking for?

syms t real
theta(t) = angle(gamma(sym(1)/sym(4) +1i*t/2)) - log(sym(pi))/2*t

theta(t) = 

tsol = vpasolve(theta(t) == 2)

tsol = 

vpa(theta(tsol))

ans = 

2.0

[bil]

Yes great, this is it!

Thanks so much.