# invlink

## PURPOSE

inverse link function for locfit.

## SYNOPSIS

function y0 = invlink(y,fali)

## DESCRIPTION

     inverse link function for locfit.
     y is a vector of raw fitted values.
     fali is the integer [family link] vector from locfit.
     output is the inv. link.

## CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

- lfband adds confidence bands around the plot of a locfit() fit.
- lfplot Plot (for one or two dimensions) a locfit() fit.
- smooth_lf must (unlike R smooth.lf() function) give x and y.
- den_jack Function to compute smooth estimates of the mean of x using locfit,

## SOURCE CODE

    0001 function y0 = invlink(y,fali)
    0002 % inverse link function for locfit.
    0003 % y is a vector of raw fitted values.
    0004 % fali is the integer [family link] vector from locfit.
    0005 % output is the inv. link.
    0006
    0007 link = fali(2);
    0008
    0009 switch(link)
    0010     case 3   % identity
    0011         y0 = y;
    0012     case 4   % log
    0013         y0 = exp(y);
    0014     case 5   % logit - should invert carefully!
    0015         y0 = 1 - 1./(1+exp(y));
    0016     case 6   % inverse
    0017         y0 = 1/y;
    0018     case 7   % sqrt
    0019         y0 = y*abs(y);
    0020     case 8   % arcsin
    0021         y0 = sin(y)*sin(y);
    0022     otherwise
    0023         disp('invlink: Unknown link function');
    0024 end;