SIMD Refactor: Merge simd-dev into dev (#55)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: aider (openrouter/anthropic/claude-sonnet-4) <aider@aider.chat>
Co-authored-by: Warp <agent@warp.dev>

lib/volatility/natr/natr.pine

@@ -0,0 +1,40 @@
+// The MIT License (MIT)
+// © mihakralj
+//@version=6
+indicator("Normalized Average True Range", "NATR", overlay=false, format=format.percent, precision=2)
+
+//@function Calculates the Normalized Average True Range (NATR)
+//@param length The period length for the ATR calculation.
+//@returns The NATR value as a percentage of close price.
+//@optimized Beta precomputation for RMA warmup compensation
+natr(simple int length) =>
+    if length <= 0
+        runtime.error("Period must be greater than 0")
+    float prevClose = nz(close[1], close)
+    float tr1 = high - low
+    float tr2 = math.abs(high - prevClose)
+    float tr3 = math.abs(low - prevClose)
+    float trueRange = math.max(tr1, math.max(tr2, tr3))
+    float alpha = 1.0 / float(length)
+    float beta = 1.0 - alpha
+    var float EPSILON = 1e-10
+    var float raw_rma = 0.0
+    var float e = 1.0
+    float atrValue = na
+    if not na(trueRange)
+        raw_rma := (raw_rma * (length - 1) + trueRange) / length
+        e *= beta
+        atrValue := e > EPSILON ? raw_rma / (1.0 - e) : raw_rma
+    float natrValue = close != 0 ? (atrValue / close) * 100 : 0
+    natrValue
+
+// ---------- Main loop ----------
+
+// Inputs
+i_length = input.int(14, "Length", minval=1, tooltip="Number of bars used for the ATR calculation")
+
+// Calculation
+natrValue = natr(i_length)
+
+// Plot
+plot(natrValue, "NATR", color=color.yellow, linewidth=2)