mApproxPoly2: Interactive applet for exploring fitting multivariate models

In mosaicManip: Project MOSAIC (mosaic-web.org) manipulate examples.

Description

Displays a shaded level and contour plot. A circle in which z values are fitted based on the best linear combination of terms selected is overplotted. Root mean squared error of the fit is displayed as the title.

Usage

mApproxPoly2(expr, ..., xlim = c(0,1), ylim = c(0,1))

Arguments

expr	A mathematical formula of two variables of the form f(x,y)~x&y)
...	Extra arguments to be passed with expr as part of the mathematical function. Generally these are not evaluated.
xlim	The limits of the x axis.
ylim	The limits of the y axis.

Details

The x and y sliders change where in the plane the circle is centered, and the radius slider adjusts how large the circle of fitted values is. Each checkbox adds the indicated term to the fitted function. The circle transparency slider controls the transparency of the circle, where 1 is opaque and 0 is invisible - it is an alpha transparency. Number of pixels controls how many points are in the square grid upon which the function is calculated. mApproxPoly2 may run slower at higher pixel counts. Approximate number of contour lines is a slider that controls the number of contour lines through the pretty algorithm such that they are evenly spaced at nice intervals.

Value

A function that implements and displays the colored level plot contour plot of a given two-dimensional function, and plots a best fit function with selected variables in a transparent circle over the plot.

Author(s)

Andrew Rich ([e-mail]) and Daniel Kaplan ([e-mail])

Examples

if(require(manipulate)) {
mApproxPoly2(sin(x*y)~x&y)
mApproxPoly2(sin(x*y)+cos(x)~x&y, xlim=c(0,5), ylim=c(0,5))
}

mosaicManip documentation built on May 2, 2019, 5:48 p.m.