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pub struct NesterovStepper {
t: f64,
accelerated: bool,
}
impl NesterovStepper {
pub fn new(accelerated: bool) -> NesterovStepper {
NesterovStepper { t: 1.0,
accelerated }
}
pub fn omega(&mut self) -> f64 {
if self.accelerated {
let t_ = 0.5 * (1.0 + (4.0 * self.t * self.t + 1.0).sqrt());
let om = (self.t - 1.0) / t_;
self.t = t_;
om
} else {
0.0
}
}
}
pub fn l2sq(x: &[f64]) -> f64 {
let mut sum: f64 = 0.0;
for val in x.iter() {
sum += *val * *val;
}
sum
}