The Directional Movement Index (DMI) is an indicator that was developed by J. Welles Wilder in 1978. It is used to identify the direction in which the price of an asset is moving. The DMI is composed of two lines, the DMI+ and the DMI-. The DMI+ is calculated by adding the difference between the high and the low of the current period to the absolute value of the difference between the high and the low of the previous period. The DMI- is calculated by adding the difference between the high and the low of the current period to the absolute value of the difference between the high and the low of the previous period. The DMI+ line is plotted on top of the DMI- line. A crossover of the two lines indicates a change in the direction of the price.DMI = (DMI+ - DMI-) / (DMI+ + DMI-)DMI+ = the average of the highs over the past N periodsDMI- = the average of the lows over the past N periods
The indicator consists of two lines: a fast line and a slow line. The fast line measures the strength of the up or down move, while the slow line measures how long this move has been going on for. When these lines cross, it can be interpreted as a change in trend and could be used to enter into a trade.