posvolidx - Positive volume index

Syntax

pvi = posvolidx(closep, tvolume, initpvi)
pvi = posvolidx([closep tvolume], initpvi)
pvits = posvolidx(tsobj)
pvits = posvolidx(tsobj, initpvi, ParameterName, ParameterValue, ...)

Arguments

`closep`	Closing price (vector).
`tvolume`	Volume traded (vector).
`initpvi`	(Optional) Initial value for positive volume index. Default = 100.
`tsobj`	Financial time series object.

Description

pvi = posvolidx(closep, tvolume, initpvi) calculates the positive volume index from a set of stock closing prices (closep) and volume traded (tvolume) data. pvi is a vector representing the positive volume index. If initpvi is specified, posvolidx uses that value instead of the default (100).

pvi = posvolidx([closep tvolume], initpvi) accepts a two-column matrix, the first column representing the closing prices (closep) and the second representing the volume traded (tvolume). If initpvi is specified, posvolidx uses that value instead of the default (100).

pvits = posvolidx(tsobj) calculates the positive volume index from the financial time series object tsobj. The object must contain, at least, the series Close and Volume. The pvits output is a financial time series object with dates similar to tsobj and a data series named PVI. The initial value for the positive volume index is arbitrarily set to 100.

pvits = posvolidx(tsobj, initpvi, ParameterName, ParameterValue,...) accepts parameter name/parameter value pairs as input. These pairs specify the name(s) for the required data series if it is different from the expected default name(s). Valid parameter names are

CloseName: closing prices series name
VolumeName: volume traded series name

Parameter values are the strings that represent the valid parameter names.

Examples

Compute the positive volume index for Disney stock and plot the results:

load disney.mat
dis_PosVol = posvolidx(dis)
plot(dis_PosVol)
title('Positive Volume Index for Disney')

References

Achelis, Steven B., Technical Analysis from A to Z, Second printing, McGraw-Hill, 1995, pp. 236 - 238.