Update EMAFilter.java

refactor: simplify EMAFilter implementation

- Reduce verbose comments to essential formula
- Shorten variable names (emaValue -> ema, audioSignal -> signal)
- Condense constructor validation and initialization
- Maintain identical functionality and behavior

Author: ShreyanshJain105

src/main/java/com/thealgorithms/audiofilters/EMAFilter.java

@@ -1,48 +1,28 @@
 package com.thealgorithms.audiofilters;
 
 /**
- * Exponential Moving Average (EMA) Filter for smoothing audio signals.
- *
- * <p>This filter applies an exponential moving average to a sequence of audio
- * signal values, making it useful for smoothing out rapid fluctuations.
- * The smoothing factor (alpha) controls the degree of smoothing.
- *
- * <p>Based on the definition from
- * <a href="https://en.wikipedia.org/wiki/Moving_average">Wikipedia link</a>.
+ * EMA Filter for audio signal smoothing.
+ * Formula: EMA[i] = alpha * signal[i] + (1-alpha) * EMA[i-1]
  */
 public class EMAFilter {
     private final double alpha;
-    private double emaValue;
-    /**
-     * Constructs an EMA filter with a given smoothing factor.
-     *
-     * @param alpha Smoothing factor (0 < alpha <= 1)
-     * @throws IllegalArgumentException if alpha is not in (0, 1]
-     */
+    private double ema;
+
     public EMAFilter(double alpha) {
-        if (alpha <= 0 || alpha > 1) {
-            throw new IllegalArgumentException("Alpha must be between 0 and 1.");
-        }
+        if (alpha <= 0 || alpha > 1) throw new IllegalArgumentException("Alpha must be in (0,1]");
         this.alpha = alpha;
-        this.emaValue = 0.0;
     }
-    /**
-     * Applies the EMA filter to an audio signal array.
-     *
-     * @param audioSignal Array of audio samples to process
-     * @return Array of processed (smoothed) samples
-     */
-    public double[] apply(double[] audioSignal) {
-        if (audioSignal.length == 0) {
-            return new double[0];
-        }
-        double[] emaSignal = new double[audioSignal.length];
-        emaValue = audioSignal[0];
-        emaSignal[0] = emaValue;
-        for (int i = 1; i < audioSignal.length; i++) {
-            emaValue = alpha * audioSignal[i] + (1 - alpha) * emaValue;
-            emaSignal[i] = emaValue;
+
+    public double[] apply(double[] signal) {
+        if (signal.length == 0) return new double[0];
+        
+        double[] result = new double[signal.length];
+        ema = result[0] = signal[0];
+        
+        for (int i = 1; i < signal.length; i++) {
+            ema = alpha * signal[i] + (1 - alpha) * ema;
+            result[i] = ema;
         }
-        return emaSignal;
+        return result;
     }
 }