efi

// Elder's Force Index (price change times volume, EMA-smoothed)
// Defaults of "efi" (see the indicator reference)
let params = HashMap::from([
    ("ema_len".to_string(), 13.0),
]);
let mut indicator = build_checked("efi", &params)?;

for bar in &bars {
    if let Some(output) = indicator.on_bar(bar) {
        // output.value, output.extra[...], indicator.alerts()
    }
}