re-organize code in modules

src/calculations/mod.rs

@@ -0,0 +1,57 @@
+///
+/// Calculates the absolute and relative difference between the beginning and ending of an f64 series. The relative difference is relative to the beginning.
+///
+/// # Returns
+///
+/// A tuple `(absolute, relative)` difference.
+///
+pub fn price_diff(a: &[f64]) -> Option<(f64, f64)> {
+    if !a.is_empty() {
+        // unwrap is safe here even if first == last
+        let (first, last) = (a.first().unwrap(), a.last().unwrap());
+        let abs_diff = last - first;
+        let first = if *first == 0.0 { 1.0 } else { *first };
+        let rel_diff = abs_diff / first;
+        Some((abs_diff, rel_diff))
+    } else {
+        None
+    }
+}
+
+///
+/// Window function to create a simple moving average
+///
+pub fn n_window_sma(n: usize, series: &[f64]) -> Option<Vec<f64>> {
+    if !series.is_empty() && n > 1 {
+        Some(
+            series
+                .windows(n)
+                .map(|w| w.iter().sum::<f64>() / w.len() as f64)
+                .collect(),
+        )
+    } else {
+        None
+    }
+}
+
+///
+/// Find the maximum in a series of f64
+///
+pub fn max(series: &[f64]) -> Option<f64> {
+    if series.is_empty() {
+        None
+    } else {
+        Some(series.iter().fold(f64::MIN, |acc, q| acc.max(*q)))
+    }
+}
+
+///
+/// Find the minimum in a series of f64
+///
+pub fn min(series: &[f64]) -> Option<f64> {
+    if series.is_empty() {
+        None
+    } else {
+        Some(series.iter().fold(f64::MAX, |acc, q| acc.min(*q)))
+    }
+}

src/lib.rs

@@ -0,0 +1,6 @@
+pub mod calculations;
+pub mod types;
+pub mod utils;
+
+#[cfg(test)]
+mod tests;