use crate::evaluator::*;
macro_const! {
const DOC: &'static str = r#"
Standard deviation of magnitude $\sigma_m$
$$
\sigma_m \equiv \sqrt{\sum_i (m_i - \langle m \rangle)^2 / (N-1)},
$$
$N$ is the number of observations
and $\langle m \rangle$ is the mean magnitude.
- Depends on: **magnitude**
- Minimum number of observations: **2**
- Number of features: **1**
[Wikipedia](https://en.wikipedia.org/wiki/Standard_deviation)
"#;
}
#[doc = DOC!()]
#[derive(Clone, Default, Debug, Serialize, Deserialize, JsonSchema)]
pub struct StandardDeviation {}
lazy_info!(
STANDARD_DEVIATION_INFO,
StandardDeviation,
size: 1,
min_ts_length: 2,
t_required: false,
m_required: true,
w_required: false,
sorting_required: false,
);
impl StandardDeviation {
pub fn new() -> Self {
Self {}
}
pub fn doc() -> &'static str {
DOC
}
}
impl FeatureNamesDescriptionsTrait for StandardDeviation {
fn get_names(&self) -> Vec<&str> {
vec!["standard_deviation"]
}
fn get_descriptions(&self) -> Vec<&str> {
vec!["standard deviation of magnitude sample"]
}
}
impl<T> FeatureEvaluator<T> for StandardDeviation
where
T: Float,
{
fn eval(&self, ts: &mut TimeSeries<T>) -> Result<Vec<T>, EvaluatorError> {
self.check_ts_length(ts)?;
Ok(vec![ts.m.get_std()])
}
}
#[cfg(test)]
#[allow(clippy::unreadable_literal)]
#[allow(clippy::excessive_precision)]
mod tests {
use super::*;
use crate::tests::*;
check_feature!(StandardDeviation);
feature_test!(
standard_deviation,
[StandardDeviation::new()],
[1.5811388300841898],
[0.0_f32, 1.0, 2.0, 3.0, 4.0],
);
}