From 50aca5fe89f09227c2036bb036a0c9953b094031 Mon Sep 17 00:00:00 2001
From: m5l14i11 <siarhei.melnik@proton.me>
Date: Mon, 26 Jun 2023 23:07:38 +0400
Subject: [PATCH] cache len

---
 ta_lib/momentum/src/rsi.rs | 10 ++++++----
 ta_lib/overlap/src/ema.rs  | 12 +++++++-----
 ta_lib/overlap/src/sma.rs  | 10 ++++++++--
 ta_lib/overlap/src/smma.rs | 12 +++++++-----
 4 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/ta_lib/momentum/src/rsi.rs b/ta_lib/momentum/src/rsi.rs
index 214e7aef..61a72524 100644
--- a/ta_lib/momentum/src/rsi.rs
+++ b/ta_lib/momentum/src/rsi.rs
@@ -1,12 +1,14 @@
 use overlap::smma::smma;
 
 pub fn rsi(data: &[f64], period: usize) -> Vec<Option<f64>> {
-    if data.len() < period {
-        return vec![None; data.len()];
+    let len = data.len();
+
+    if len < period {
+        return vec![None; len];
     }
 
-    let mut gains = vec![0.0; data.len()];
-    let mut losses = vec![0.0; data.len()];
+    let mut gains = vec![0.0; len];
+    let mut losses = vec![0.0; len];
 
     for i in 1..data.len() {
         let change = data[i] - data[i - 1];
diff --git a/ta_lib/overlap/src/ema.rs b/ta_lib/overlap/src/ema.rs
index f7cec8ea..459ced6f 100644
--- a/ta_lib/overlap/src/ema.rs
+++ b/ta_lib/overlap/src/ema.rs
@@ -1,16 +1,18 @@
 pub fn ema(data: &[f64], period: usize) -> Vec<Option<f64>> {
-    if data.len() < period {
-        return vec![None; data.len()];
+    let len = data.len();
+
+    if len < period {
+        return vec![None; len];
     }
 
     let alpha = 2.0 / (period as f64 + 1.0);
 
-    let mut ema = vec![None; data.len()];
-
+    let mut ema = vec![None; len];
     let mut ema_current = data[0];
 
-    for i in 1..data.len() {
+    for i in 1..len {
         ema_current = (data[i] - ema_current) * alpha + ema_current;
+
         if i >= period - 1 {
             ema[i] = Some(ema_current);
         }
diff --git a/ta_lib/overlap/src/sma.rs b/ta_lib/overlap/src/sma.rs
index 61a445ac..df39a640 100644
--- a/ta_lib/overlap/src/sma.rs
+++ b/ta_lib/overlap/src/sma.rs
@@ -1,8 +1,14 @@
 pub fn sma(data: &[f64], period: usize) -> Vec<Option<f64>> {
-    let mut sma = vec![None; data.len()];
+    let len = data.len();
+
+    if len < period {
+        return vec![None; len];
+    }
+
+    let mut sma = vec![None; len];
     let mut sum = 0.0;
 
-    for i in 0..data.len() {
+    for i in 0..len {
         sum += data[i];
 
         if i >= period {
diff --git a/ta_lib/overlap/src/smma.rs b/ta_lib/overlap/src/smma.rs
index 682fffee..8891d852 100644
--- a/ta_lib/overlap/src/smma.rs
+++ b/ta_lib/overlap/src/smma.rs
@@ -1,16 +1,18 @@
 pub fn smma(data: &[f64], period: usize) -> Vec<Option<f64>> {
-    if data.len() < period {
-        return vec![None; data.len()];
+    let len = data.len();
+
+    if len < period {
+        return vec![None; len];
     }
 
     let alpha = 1.0 / period as f64;
 
-    let mut smma = vec![None; data.len()];
-
+    let mut smma = vec![None; len];
     let mut smma_current = data[0];
 
-    for i in 1..data.len() {
+    for i in 1..len {
         smma_current = (data[i] - smma_current) * alpha + smma_current;
+
         if i >= period - 1 {
             smma[i] = Some(smma_current);
         }