Windows users in my courses have had problems with the following model crashing RStudio,

```
functions {
// Difference between one-sided Gaussian tail probability and target probability
vector tail_delta(vector y, vector theta, real[] x_r, int[] x_i) {
vector[1] deltas;
deltas[1] = 2 * (normal_cdf(theta[1], 0, exp(y[1])) - 0.5) - 0.99;
return deltas;
}
}
transformed data {
vector[1] y_guess = [log(5)]'; // Initial guess of Gaussian standard deviation
vector[1] theta = [15]'; // Target quantile
vector[1] y;
real x_r[0];
int x_i[0];
// Find Gaussian standard deviation that ensures 99% probabilty below 15
y = algebra_solver(tail_delta, y_guess, theta, x_r, x_i);
print("Standard deviation = ", exp(y[1]));
}
generated quantities {
real sigma = exp(y[1]);
}
```

I havenâ€™t had anyone testing it on PyStan on Windows, but it works in RStan and PyStan on OS X and at least some versions of Linux.

Can anyone who has access to Windows verify a problem and/or help isolate what the issue might be? I fear a bug in the algebraic solver thatâ€™s manifesting only in Windows.