GroupSeq (version 1.0)

jointDensity: calculates the join density

Description

This function calculates the join density at eather first analysis ( i==1) or at second analysis and later ( i > 1)

Usage

jointDensity(i, lowerIntegrationLimit, upperIntegrationLimit, standardDeviation, numberOfIntegrationIntervalls, lastGrid)

Arguments

i

denotes the i-th interim analysis

lowerIntegrationLimit

is the lower integration limit for the first analysis.

upperIntegrationLimit

is the upper integration limit for the first analysis.

standardDeviation

is the standard deviation of the process at first analysis.

numberOfIntegrationIntervalls

is the number of whole steps between lowerIntegrationLimit and upperIntegrationLimit.

lastGrid

is the vector of function values over the grid.

Value

• lastCopy
  a temporary vector of function values because 'lastGrid' from previous step itself is needed to compute each current value.

References

This refers to Fortran Implementation from http://www.biostat.wisc.edu/landemets/

See Also

groupseq, dnorm integrateByTrapez

Examples

## function depends heavily on calculations before (e.g.the 'numberOfIntegrationIntervalls' or 'lastGrid'), 
## so you don�t want to use it by manual and therefore an example is not useful