Smoothed Fisher Transform

A custom indicator created by James on TrendSpider. You can import this custom indicator into your TrendSpider account. Don't have TrendSpider? Create an account first, then import the custom indicator.

Source code

This indicator had been implemented by James in JavaScript on TrendSpider. Check out the developer documentation to learn more about JS on TrendSpider.

describe_indicator("Smoothed Fisher Transform", "lower", { decimals: 3, shortName: "SFT" });

const rangePeriods = input("Range Periods", 30, { min: 1, max: 200 });
const priceSmoothing = input("Price Smoothing", 0.3, { min: 0, max: 1 });
const indexSmoothing = input("Index Smoothing", 0.3, { min: 0, max: 1 });
const emaLength = input("EMA Length", 20, { min: 1, max: 100 });
const emaLength2 = input("EMA Length 2", 5, { min: 1, max: 100 });

// Highest high and lowest low
const highestHigh = sliding_window_function(high, rangePeriods, values => Math.max(...values));
const lowestLow = sliding_window_function(low, rangePeriods, values => Math.min(...values));

// Price location calculation
const midPrice = div(add(high, low), 2);
const greatestRange = sub(highestHigh, lowestLow);
const priceLocation = sub(div(mult(sub(midPrice, lowestLow), 2), greatestRange), 1);

// Smooth price location
const smoothedLocation = sliding_window_function(priceLocation, 2, window => {
    let extMapBuffer = priceSmoothing * window[1] + (1 - priceSmoothing) * window[0];
    return Math.min(Math.max(extMapBuffer, -0.99), 0.99);
});

// Fisher Transform calculation
const fishIndex = sliding_window_function(smoothedLocation, 1, values => Math.log((1 + values[0]) / (1 - values[0])));

// Smooth Fisher Transform
const smoothedFish = sliding_window_function(fishIndex, 2, window => indexSmoothing * window[1] + (1 - indexSmoothing) * window[0]);

// EMA calculations
const ema1 = ema(smoothedFish, emaLength);
const ema2 = ema(smoothedFish, emaLength2);

// Plotting
paint(ema1, "EMA 1", "#00FFFF");
paint(ema2, "EMA 2", "#FFFFFF");
paint(smoothedFish, "Fish Histogram", smoothedFish[smoothedFish.length - 1] > 0 ? "green" : "red", "histogram");