DEMA (Double Exponential Moving Average)

DEMA reduces the lag inherent in traditional moving averages by applying the EMA formula twice and adjusting. It is more responsive to price changes than a standard EMA.

Declaration

function init(ctx) {
  ctx.indicator('dema', 'DEMA', { period: 21, source: 'close' });
}

Options

Option	Type	Default	Description
`period`	`number`	20	Lookback period
`source`	`string`	`'close'`	Price source (`open`, `high`, `low`, `close`, `hl2`, `hlc3`, `ohlc4`)

Output

Returns a single number[] series.

Accessing Values

function onBar(ctx, i) {
  const demaValue = ctx.ind.dema[i];
}

Use Cases

Fast Trend Detection

function init(ctx) {
  ctx.indicator('dema', 'DEMA', { period: 21 });
  ctx.indicator('ema', 'EMA', { period: 21 });
}

function onBar(ctx, i) {
  // DEMA turns before EMA at trend reversals
  if (q.crossOver(ctx.ind.dema, ctx.ind.ema, i)) {
    ctx.order.market('ASSET', 1, { signal: 'buy', reason: 'dema_leads' });
  }
}

Calculation

$$DEMA = 2 \times EMA(Price) - EMA(EMA(Price))$$

EMA - Standard exponential moving average
TEMA - Triple EMA for even less lag
SMA - Simple moving average