Inger, Matthew napisał(a): > returning a RealMatrix for the coefficients doesn't make sense > to me, since a matrix implies N x M dimensions, and the coefficient > matrix has a fixed number of rows (1). I'd rather return an double[] > instance. However, that array is available through LinearFunction > as i have outlined it below, so it's not really hard to get to it: > > results.getFuntion().getCoefficients();
This way of obtaining coefficients might be natural and elegant for a Java programmer, but I think that average statistician would prefere to get them in a simpler way, without digging through interfaces, methods, etc. just to find such a basic result. As I understand rationale behind returning RealMatrix is that there is a number of usefull methods that makes manipulation with the result easier, but I would not complain if I get double[], I would not have to think about some additional interface (RealMatrix). In addition double[] can be easily converted to RealMatrix if it is needed. Piotr > > -----Original Message----- > From: Phil Steitz [mailto:[EMAIL PROTECTED] > Sent: Monday, January 26, 2004 4:59 PM > To: Jakarta Commons Developers List > Subject: RE: [math] - Multiple Linear Regression > > > --- "Inger, Matthew" <[EMAIL PROTECTED]> wrote: > > Is there any plan to possibly have a MultivariateRealFunction interface? > > I had planned to return the linear regression coefficients in > > the form of a linear function: > > > > public interface MultivariateRealFunction > > { > > public double value(double x[]); > > } > > > > // in package "linear" > > > > // a function of the form: > > // y = b0 + b1*x1 + b2*x2 + ... bn*xn > > public class LinearFunction > > implements MultivariateRealFunction > > { > > public double value(double x[]) { ... }; > > public int getCoefficientCount() { ... }; > > public double getCoefficientAt(int idx) { ... }; > > public double[] getCoefficients() { ... }; > > } > > > > > > public class LinearRegressionResults > > { > > public LinearFunction getFunction() { ... }; > > public double[] getResidual(); > > ... > > // put in all the other statistical values here > > } > > > > public class LinearRegresion > > { > > public LinearRegressionResults > > solve(double x[][], double y[]) { ... }; > > } > > > > Thoughts? > > > That is an interesting approach, but I suspect that users of this class are > going to be primarily interested in the vector of estimated coefficients as > well as standard errors and other model statistics. I would prioritize > getting the parameter estimates and standard errors represented and > available. I have no problem including a predict() method (or even > returning a function) that uses the coefficients to produce predicted > values based on the model, but I would be happy (actually happier) with a > (row) RealMatrix of coefficients. > > Phil > > __________________________________ > Do you Yahoo!? > Yahoo! SiteBuilder - Free web site building tool. Try it! > http://webhosting.yahoo.com/ps/sb/ > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
