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### Auto Retracement/Projection

The **Auto Retracement/Projection** study automatically calculates and displays *retracement* or *projection* lines based upon the High to Low price range for the specified time period.

The time period is set with the **Time Period Unit** and the **Time Period Unit Length** Inputs.

For each bar in the chart, the High and Low for the specified time period is determined up to that bar and not beyond, and the percentages specified with the **Level 1-14 Percentage** Inputs are used to calculate the retracement/projection lines for that bar.

When the **Calculation Method** is Retracement and the High is the reference value, controlled by the **Calculation Reference Value** Input, each of the percentages are multiplied by the High to Low price range and added to the Low to create the retracement levels.

When the **Calculation Method** is Retracement and the Low is the reference value, controlled by the **Calculation Reference Value** Input, each of the percentages are multiplied by the High to Low price range and subtracted from the High to create the retracement levels.

As the High to Low price range changes for the time period, then the retracement/projection levels will also change because the price range is changing.

When the **Calculation Reference Value** Input is set to **Automatic**, then in the case of either a Retracement or Projection calculation, the study looks at the opening price for the time period and compares it to the closing price of a bar to know whether the Retracement or Projection lines should be calculated from the High or the Low price.

In the case when prices are declining and the **Calculation Method** is Retracement, then the Retracement lines are calculated from the **Low** of the period. In the case when prices are rising and the **Calculation Method** is Retracement, then the Retracement lines are calculated from the **High** of the period.

When the **Calculation Reference Value** Input is set to **Automatic**, then during the time period for which the Retracement/Projection lines are for, if there is a change with the relationship between the Open price for the time period and the current Close/Last price at a bar, then this will cause at that bar a reversal of the calculations which are described in the prior paragraph.

For example, the Close was previously above the Open, but on the bar currently being calculated it is below the Open. This will cause a reversal of the calculation.

#### Inputs

- Time Period Unit
- Time Period Unit Length
**Calculation Method**: This Input sets the calculation method. This can either be**Projection**or**Retracement**. A**Projection**places the lines going upward from the Period High. A**Retracement**places the lines going downward from the Period High.**Level 1-14 Percentage**: This Input specifies the percentages for the Retracement/Projection lines. .01 equals 1%.**New Period at Day Session Start When Using Evening Session**: When this Input is set to**Yes**and Evening Session Times are defined in the Session Times, then the calculation will reset and there will be a new period at the beginning of the evening session. This only applies to Intraday charts.**Calculation Reference Value**: This sets the reference level for the retracement/projection line calculations to be either**Automatic**, or specifically from the**High**or the**Low**for the specified time period.**Round to Nearest Tick Size**: When this Input is set to**Yes**, then the retracement/projection levels are rounded to the**Tick Size**setting in Chart Settings.**Reference Single Subgraph**: This Input is used when the**Auto Retracement/Projection**study is set to be Based On a study other than the main price graph. In this particular case, when this Input is set to**Yes**, then the first Subgraph that**Auto Retracement/Projection**study is set to be based on, will be used. This is necessary for this study to function properly.

When the**Auto Retracement/Projection**study is based on another study and that study has not set values in its Subgraph at each chart bar and those Subgraph values are at a zero value, then this will affect the output of Auto Retracement/Projection study at those chart bars causing it to display invalid values. While this is not the most ideal solution for this kind of condition, the solution to this is to set the Scale Range for the Auto Retracement/Projection study to**Same as Region**to prevent those invalid values from affecting the display of the study.**Number of Days to Calculate**: This Input specifies the number of days to calculate the Retracement/Projection for. This value is always in**Days**regardless of the Input setting**Time Period Unit**. In order for the calculations to be correct, this value must be at least the number of days covered by the**Time Period Unit**and the**Time Period Unit Length**. For example, if the**Time Period Unit**is**Weeks**and the**Time Period Unit Length**is**2**, then the**Number of Days to Calculate**should be set to a value of at least**14**.

Additionally, as new chart bars are added to the chart during updating, the number of days that the study is calculated over will gradually increase corresponding to those new bars added to the chart. In this case you will need to select**Chart >> Recalculate**to cause the chart to only calculate across the**Number of Days to Calculate**.

*Last modified Friday, 16th February, 2018.