FSCorAnaeda

FSCorAnaeda performs forward search in correspondence analysis with exploratory data analysis purposes

Syntax

• out=FSCorAnaeda(N)example
• out=FSCorAnaeda(N,Name,Value)example

Description

 out =FSCorAnaeda(N) FSCorAnaeda with all default options.

 out =FSCorAnaeda(N, Name, Value) FSCorAnaeda with optional arguments.

Examples

expand all

FSCorAnaeda with all default options.

Generate contingency table of size 50-by-5 with total sum of n_ij=2000.

I=50;
J=5;
n=2000;
% nrowt = column vector containing row marginal totals
nrowt=(n/I)*ones(I,1);
% ncolt = row vector containing column marginal totals
ncolt=(n/J)*ones(1,J);
out1=rcontFS(I,J,nrowt,ncolt);
N=out1.m144;
RAW=mcdCorAna(N,'plots',0);
ini=round(sum(sum(RAW.N))/4);
out=FSCorAnaeda(RAW);

FSCorAnaeda with optional arguments.

Generate contingency table of size 50-by-5 with total sum of n_ij=2000.

I=50;
J=5;
n=2000;
% nrowt = column vector containing row marginal totals
nrowt=(n/I)*ones(I,1);
% ncolt = row vector containing column marginal totals
ncolt=(n/J)*ones(1,J);
out1=rcontFS(I,J,nrowt,ncolt);
N=out1.m144;
RAW=mcdCorAna(N,'plots',0);
ini=round(sum(sum(RAW.N))/4);
out=FSCorAnaeda(RAW,'plots',1);
Total estimated time to complete MCD:  0.62 seconds
Creating empirical confidence band for minimum (weighted) Mahalanobis distance


Related Examples

expand all

FSCorAnaeda starting from a random initial subset.

Generate contingency table of size 50-by-5 with total sum of n_ij=2000.

I=50;
J=5;
n=2000;
% nrowt = column vector containing row marginal totals
nrowt=(n/I)*ones(I,1);
% ncolt = row vector containing column marginal totals
ncolt=(n/J)*ones(1,J);
out1=rcontFS(I,J,nrowt,ncolt);
N=out1.m144;
% The first input argument is a contingency table and no initial subset
% and no initial location is supplied
out=FSCorAnaeda(N,'plots',1);

Input Arguments

N — contingency table or structure. Array or table of size I-by-J or strucure.

If N is a structure it contains the following fields:

N.N = contingency table in array format of size I-by-J.

N.loc = initial location estimate for the matrix of Profile rows of the contingency table (row vector or length J).

Note that input structure N can be conveniently created by function mcdCorAna.

If N is not a struct it is possible to specify the unitf forming initial subset with input option bsb.

Data Types: single|double

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside single quotes (' '). You can specify several name and value pair arguments in any order as  Name1,Value1,...,NameN,ValueN.

Example:  'bsb',[3 6 8 10 12 14] , 'init',50 , 'plots',0 , 'msg',0 

bsb —Initial subset.vector of positive integers containing the indexes of the rows of the contingency table which have to be used to initialize the forward search.

If bsb is empty and required input argument is a struct N.loc will be used.

If bsb is supplied and N is a struct N.loc is ignored.

The default value of bsb is empty, and if N is struct a random subset containing round(n/5) units will be used.

Example:  'bsb',[3 6 8 10 12 14] 

Data Types: double

init —Point where to start monitoring required diagnostics.scalar.

Note that if init is not specified it will be set equal to floor(n*0.6).

where the total number of units in the contingency table.

Example:  'init',50 

Data Types: double

plots —It specify whether it is necessary to produce the plots of the monitoring of minMD.scalar.

If plots=1, a plot of the monitoring of minMD among the units not belonging to the subset is produced on the screen with 1 per cent, 50 per cent and 99 per cent confidence bands else (default), all plots are suppressed.

Example:  'plots',0 

Data Types: double

msg —It controls whether to display or not messages about great interchange on the screen.scalar.

If msg==1 (default) messages are displyed on the screen else no message is displayed on the screen.

Example:  'msg',0 

Data Types: double

Output Arguments

out — description Structure

Structure which contains the following fields

Value Description
MAL

I x (n-init+1) = matrix containing the monitoring of Mahalanobis distances.

1st row = distance for first row;

...;

Ith row = distance for Ith row.

BB

I-by-(n-init+1) matrix containing the information about the units belonging to the subset at each step of the forward search.

1st col = indexes of the units forming subset in the initial step;

...;

last column = units forming subset in the final step (all units).

mmd

n-init-by-2 matrix which contains the monitoring of minimum MD or (m+1)th ordered MD at each step of the forward search.

1st col = fwd search index (from init to n-1);

2nd col = minimum MD;

Loc

(n-init+1)-by-J matrix containing the monitoring of estimated means for each variable in each step of the forward search.

Un

(n-init) x 11 Matrix which contains the unit(s) included in the subset at each step of the fwd search.

REMARK: in every step the new subset is compared with the old subset. Un contains the unit(s) present in the new subset but not in the old one Un(1,2) for example contains the unit included in step init+1 Un(end,2) contains the units included in the final step of the search

N

Original contingency table, in array format.

Y

array of size I-by-J containing row profiles.

class

'FSCorAnaeda'

References

Atkinson, A.C., Riani, M. and Cerioli, A. (2004), "Exploring multivariate data with the forward search", Springer Verlag, New York.