nag_binary_factor_service (g11sbc) (PDF version)
g11 Chapter Contents
g11 Chapter Introduction
NAG C Library Manual

NAG Library Function Document

nag_binary_factor_service (g11sbc)

+ Contents

    1  Purpose
    7  Accuracy

1  Purpose

nag_binary_factor_service (g11sbc) is a service function which may be used prior to calling nag_binary_factor (g11sac) to calculate the frequency distribution of a set of dichotomous score patterns.

2  Specification

#include <nag.h>
#include <nagg11.h>
void  nag_binary_factor_service (Nag_OrderType order, Integer p, Integer n, Integer *ns, Nag_Boolean x[], Integer pdx, Integer irl[], NagError *fail)

3  Description

When each of n individuals responds to each of p dichotomous variables the data assumes the form of the matrix X defined below
X= x11 x12 x1p x21 x22 x2p xn1 xn2 xnp = x̲1 x̲2 x̲n ,
where the x take the value of 0 or 1 and x̲l=xl1,xl2,,xlp, for l=1,2,,n, denotes the score pattern of the lth individual. nag_binary_factor_service (g11sbc) calculates the number of different score patterns, s, and the frequency with which each occurs. This information can then be passed to nag_binary_factor (g11sac).

4  References


5  Arguments

1:     orderNag_OrderTypeInput
On entry: the order argument specifies the two-dimensional storage scheme being used, i.e., row-major ordering or column-major ordering. C language defined storage is specified by order=Nag_RowMajor. See Section in the Essential Introduction for a more detailed explanation of the use of this argument.
Constraint: order=Nag_RowMajor or Nag_ColMajor.
2:     pIntegerInput
On entry: p, the number of dichotomous variables.
Constraint: p3.
3:     nIntegerInput
On entry: n, the number of individuals in the sample.
Constraint: n7.
4:     nsInteger *Output
On exit: the number of different score patterns, s.
5:     x[dim]Nag_BooleanInput/Output
Note: the dimension, dim, of the array x must be at least
  • max1,pdx×p when order=Nag_ColMajor;
  • max1,n×pdx when order=Nag_RowMajor.
Where Xi,j appears in this document, it refers to the array element
  • x[j-1×pdx+i-1] when order=Nag_ColMajor;
  • x[i-1×pdx+j-1] when order=Nag_RowMajor.
On entry: Xi,j must be set equal to Nag_TRUE if xij=1, and Nag_FALSE if xij=0, for i=1,2,,n and j=1,2,,p.
On exit: the first s rows of x contain the s different score patterns.
6:     pdxIntegerInput
On entry: the stride separating row or column elements (depending on the value of order) in the array x.
  • if order=Nag_ColMajor, pdxn;
  • if order=Nag_RowMajor, pdxp.
7:     irl[n]IntegerOutput
On exit: the frequency with which the lth row of x occurs, for l=1,2,,s.
8:     failNagError *Input/Output
The NAG error argument (see Section 3.6 in the Essential Introduction).

6  Error Indicators and Warnings

Dynamic memory allocation failed.
On entry, argument value had an illegal value.
On entry, n=value.
Constraint: n7.
On entry, p=value.
Constraint: p3.
On entry, pdx=value.
Constraint: pdx>0.
On entry, pdx=value and n=value.
Constraint: pdxn.
On entry, pdx=value and p=value.
Constraint: pdxp.
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.

7  Accuracy


8  Further Comments

The time taken by nag_binary_factor_service (g11sbc) is small and increases with n.

9  Example

This example counts the frequencies of different score patterns in the following list:
Score Patterns

9.1  Program Text

Program Text (g11sbce.c)

9.2  Program Data

Program Data (g11sbce.d)

9.3  Program Results

Program Results (g11sbce.r)

nag_binary_factor_service (g11sbc) (PDF version)
g11 Chapter Contents
g11 Chapter Introduction
NAG C Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2012