How To Calculate Average Directional Index (ADX) in Lisp?

@coleman 

To calculate Average Directional Index (ADX) in Lisp, you can use the following formula:

ADX = 100 * EMA((+DI - (-DI)) / (+DI + (-DI)), N)

where:

• EMA is the Exponential Moving Average function
• +DI is the Positive Directional Index
• -DI is the Negative Directional Index
• N is the period for calculating the ADX

Here is a sample Lisp code snippet to calculate the ADX for a given set of positive and negative directional indices:

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(defun calculate-emd (values n)
  (let ((alpha (/ 2 (+ n 1)))
       (ema (first values)))
    (dotimes (i (length values) ema)
      (setf ema (+ (* alpha (nth i values))
                   (* (- 1 alpha) ema)))))

(defun calculate-adx (+DI -DI n)
  (let* ((diff (/ (- +DI -DI) (+ +DI -DI)))
         (adx (calculate-ema (list diff) n)))
    (* 100 adx)))

(defun main ()
  (let* ((+DI 20)
         (-DI 15)
         (n 14)
         (adx (calculate-adx +DI -DI n)))
    (format t "ADX: ~a" adx)))

(main)

You can customize this code snippet to suit your specific requirements and input data.

@coleman 

Below is a breakdown of the code provided to help you understand how it calculates the Average Directional Index (ADX) in Lisp:

1. (defun calculate-ema (values n) ...): This function calculates the Exponential Moving Average (EMA) of a list of values with a given period n. It initializes the EMA value as the first element in the values list and then iterates over the values to calculate the EMA. The calculation of EMA is done using the formula: EMA = (value * alpha) + (EMA_previous * (1 - alpha)) where alpha = (2 / (n + 1)).
2. (defun calculate-adx (+DI -DI n) ...): This function calculates the ADX using the EMA of the difference between the Positive Directional Index +DI and Negative Directional Index -DI. It calculates the difference between +DI and -DI, then calculates the EMA of this difference with the period n. Finally, it multiplies the calculated EMA by 100 to get the ADX value.
3. (defun main () ...): This function sets the values for +DI, -DI, and period n, calls the calculate-adx function to get the ADX value, and prints it.

You can run this code in a Lisp environment to calculate the Average Directional Index for your given Positive Directional Index, Negative Directional Index, and period values. Make sure to provide valid data inputs to get the correct ADX value.