public class SinhIsingModel
extends IntegrableModel
The "sinh-Ising model" is an amalgamation of the sinh-Gordon and the Ising models.
Its scattering function is minus the sinh-Gordon scattering function:
\[ S(\zeta) = - \frac{\sinh \zeta - i \sin B \pi/2 }{\sinh \zeta + i \sin B \pi/2 }. \]
Correspondingly, the minimal solution is a product of the sinh-Gordon
minimal solution and that of the Ising model, with an additional factor to cancel the double zero at \( \zeta=0 \).
Explicitly,
\[ F_\text{min}(\theta + i\pi) = \frac{F_\text{min,sinh-Gordon}(\theta + i\pi)}{ \cosh (\theta/2) } . \]