Use i64 instead of u64 to represent timestamps

Author: sd2k

crates/augurs-prophet/src/error.rs

@@ -69,5 +69,5 @@ pub enum Error {
     /// This can happen if the dates are not evenly spaced, and
     /// there is no frequency that appears more often than others.
     #[error("Unable to infer frequency from dates: {0:?}")]
-    UnableToInferFrequency(Vec<u64>),
+    UnableToInferFrequency(Vec<TimestampSeconds>),
 }

crates/augurs-prophet/src/lib.rs

@@ -19,7 +19,7 @@ mod testdata;
 mod util;
 
 /// A timestamp represented as seconds since the epoch.
-pub type TimestampSeconds = u64;
+pub type TimestampSeconds = i64;
 
 // Re-export everything at the root so that users don't have to
 // navigate the module hierarchy.

crates/augurs-prophet/src/prophet.rs

@@ -226,7 +226,7 @@ impl Prophet {
         };
         let freq = Self::infer_freq(history_dates)?;
         let last_date = *history_dates.last().ok_or(Error::NotEnoughData)?;
-        let n = horizon.get() as u64 + 1;
+        let n = (horizon.get() as u64 + 1) as TimestampSeconds;
         let dates = (last_date..last_date + n * freq)
             .step_by(freq as usize)
             .filter(|ds| *ds > last_date)

crates/augurs-prophet/src/prophet/options.rs

@@ -6,7 +6,7 @@
 
 use std::{collections::HashMap, num::NonZeroU32};
 
-use crate::{FeatureMode, Holiday, PositiveFloat, TrendIndicator};
+use crate::{FeatureMode, Holiday, PositiveFloat, TimestampSeconds, TrendIndicator};
 
 /// The type of growth to use.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
@@ -83,7 +83,7 @@ pub struct OptProphetOptions {
     /// An optional list of changepoints.
     ///
     /// If not provided, changepoints will be automatically selected.
-    pub changepoints: Option<Vec<u64>>,
+    pub changepoints: Option<Vec<TimestampSeconds>>,
 
     /// The number of potential changepoints to include.
     ///
@@ -215,7 +215,7 @@ pub struct ProphetOptions {
     /// An optional list of changepoints.
     ///
     /// If not provided, changepoints will be automatically selected.
-    pub changepoints: Option<Vec<u64>>,
+    pub changepoints: Option<Vec<TimestampSeconds>>,
 
     /// The number of potential changepoints to include.
     ///

crates/augurs-prophet/src/prophet/prep.rs

@@ -577,7 +577,10 @@ impl Prophet {
         Ok(n)
     }
 
-    fn construct_holidays(&self, _ds: &[u64]) -> Result<HashMap<String, Holiday>, Error> {
+    fn construct_holidays(
+        &self,
+        _ds: &[TimestampSeconds],
+    ) -> Result<HashMap<String, Holiday>, Error> {
         let mut all_holidays = self.opts.holidays.clone();
         // TODO: handle country holidays.