# Documentation

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# volroc

Volume rate of change

## Syntax

```vroc = volroc(tvolume,nTimes)
vrocts = volroc(tsobj,nTimes)
vrocts = volroc(tsobj,nTimes,'ParameterName',ParameterValue, ...)
```

## Arguments

 `tvolume` Volume traded. `nTimes` (Optional) Time difference. Default = `12`. `tsobj` Financial time series object.

## Description

`vroc = volroc(tvolume,nTimes)` calculates the volume rate of change, `vroc`, from the volume traded data `tvolume`. If `nTimes` is specified, the volume rate of change is calculated between the current volume and the volume `nTimes` ago.

`vrocts = volroc(tsobj,nTimes)` calculates the volume rate of change, `vrocts`, from the financial time series object `tsobj`. The `vrocts` output is a financial time series object with similar dates as `tsobj` and a data series named `VolumeROC`. If `nTimes` is specified, the volume rate of change is calculated between the current volume and the volume `nTimes` ago.

```vrocts = volroc(tsobj,nTimes,'ParameterName',ParameterValue, ...)``` specifies the name for the required data series when it is different from the default name. The valid parameter name is

• `VolumeName`: volume traded series name

The parameter value is a character vector that represents the valid parameter name.

Note, to compute a quantity over `n` periods, you must specify `n+1` for `nTimes`. If you specify `nTimes = 0`, the function returns your original time series.

## Examples

collapse all

This example shows how to compute the volume rate of change for Disney stock and plot the results.

```load disney.mat dis_VolRoc = volroc(dis); plot(dis_VolRoc) title('Volume Rate of Change for Disney')```

## References

Achelis, Steven B. Technical Analysis from A to Z. Second Edition. McGraw-Hill, 1995, pp. 310–311.