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Toh4iem9
64 lines
5.0 KiB
Markdown
64 lines
5.0 KiB
Markdown
# DSMA Professional (Deviation Scaled Moving Average)
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## 1. Summary (Introduction)
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The DSMA (Deviation Scaled Moving Average), developed by John Ehlers, is a sophisticated adaptive moving average that adjusts its speed based on a normalized measure of market volatility.
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Unlike other adaptive moving averages that rely on momentum or cycle periods, the DSMA modifies its smoothing factor (`alpha`) based on the amplitude of an internal oscillator scaled by its own standard deviation. This unique approach results in a filter with a highly desirable behavior:
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* In **high-volatility, trending markets**, the DSMA becomes **fast and responsive**, closely tracking price action to reduce lag.
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* In **low-volatility, consolidating markets**, the DSMA becomes **slow and smooth**, flattening out to effectively filter market noise and prevent whipsaw trades.
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The DSMA serves as an intelligent, all-in-one trendline that provides visual cues about both the direction of the trend and the current state of market volatility.
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## 2. Mathematical Foundations and Calculation Logic
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The DSMA is an Exponential Moving Average where the `alpha` is dynamically calculated through a multi-stage filtering process.
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### Required Components
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* **Period (N):** The primary lookback period for the calculation.
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* **Source Price (P):** The price series used for the calculation.
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### Calculation Steps (Algorithm)
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1. **"Zeros" Oscillator:** A simple, zero-mean oscillator is created by taking the difference between the current price and the price from two bars ago: `Zeros = P[0] - P[2]`. This helps to "whiten" the price spectrum.
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2. **Initial Smoothing (SuperSmoother):** The noisy "Zeros" oscillator is smoothed using a **SuperSmoother filter**. The period of this internal SuperSmoother is set to `N/2`.
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3. **Standard Deviation (RMS) Calculation:** The algorithm calculates the Root Mean Square (RMS), which is a form of standard deviation, of the smoothed oscillator's output over the last `N` bars.
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4. **Scaling:** The current value of the smoothed oscillator is divided by its RMS. This scales the oscillator's amplitude in terms of standard deviations, creating a normalized volatility measure.
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5. **Adaptive Alpha Calculation:** The final adaptive `alpha` is calculated as being directly proportional to the absolute value of the scaled oscillator:
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$\alpha = \text{Abs}(\text{Scaled Oscillator}) \times \frac{5}{N}$
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6. **Final EMA Calculation:** The DSMA is calculated using the standard EMA formula with the adaptive `alpha`:
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$\text{DSMA}_i = \alpha \times P_i + (1 - \alpha) \times \text{DSMA}_{i-1}$
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## 3. MQL5 Implementation Details
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* **Self-Contained Calculator (`DSMA_Calculator.mqh`):** The entire complex, multi-stage calculation is encapsulated within a dedicated, reusable calculator class.
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* **Heikin Ashi Integration:** An inherited `_HA` class allows the calculation to be performed seamlessly on smoothed Heikin Ashi data.
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* **Stability via Full Recalculation:** The calculation involves multiple chained, state-dependent filters. To ensure absolute stability, the indicator employs a **full recalculation** on every `OnCalculate` call.
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## 4. Parameters
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* **Period (`InpPeriod`):** The "critical period" of the filter. This single parameter controls both the lookback window for the RMS calculation and the period of the internal SuperSmoother filter (which will be `Period/2`). Ehlers' recommendation for daily charts is **40**.
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* A longer period results in a smoother, slower-adapting filter.
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* A shorter period results in a faster, more responsive filter.
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* **Applied Price (`InpSourcePrice`):** The source price for the calculation. This unified dropdown menu allows you to select from all standard and Heikin Ashi price types.
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## 5. Usage and Interpretation
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The DSMA should be used as an "intelligent" moving average that provides clear visual information about the market's current regime (trending vs. ranging).
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### **1. Adaptive Trend Following & Dynamic S/R**
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This is the primary use case. The DSMA acts as a single, adaptive trendline.
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* **In a Trending Market:** The DSMA will be angled steeply and follow the price closely. In this state, it acts as a reliable **dynamic support level** (in an uptrend) or **resistance level** (in a downtrend). Pullbacks to the DSMA line offer high-probability, trend-following entry opportunities.
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* **In a Ranging Market:** The DSMA will flatten out and move slowly. This is a clear visual signal that the market is consolidating and trend-following strategies should be avoided. The flat line acts as a "mean" or center of gravity for the price action.
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### **2. Volatility Breakout Confirmation**
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The change in the DSMA's behavior is a signal in itself.
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* **The Setup:** Identify periods where the DSMA has been flat and slow for an extended time, indicating a period of low volatility ("coiling").
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* **The Signal:** When the price breaks out of this consolidation, watch for the DSMA to "wake up." A sharp change in its angle, as it begins to accelerate and track the price, serves as a strong **confirmation** that the breakout is valid and a new trend may be starting.
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