Function price_volatility 

pub fn price_volatility(prices: &[f64]) -> FinanceResult<f64>

Volatility of simple returns computed from consecutive prices.

Examples

use finance_solution::{price_volatility, FinanceError};

assert!(price_volatility(&[100.0, 110.0, 105.0]).is_ok());
// Only one return → sample volatility undefined.
match price_volatility(&[100.0, 110.0]) {
    Err(FinanceError::Unsolvable { message }) => assert!(message.contains("two")),
    other => panic!("expected Unsolvable, got {other:?}"),
}