Hi, list i was trying to do( Projection pursuit regression ) ppr function in Mass library . It is running very good ,no problem ,but when i refered the references Friedman et al 1981 ,,and SMART guide,, i was not able to find how parametes they r geeting using least square method , if any body know how in PPR method we are finding model parameters using least square method ,becoz it seems to a continous function .......................... thanks in advance anil ANIL KUMAR( METEOROLOGIST) LRF SECTION NATIONAL CLIMATE CENTER ADGM(RESEARCH) INDIA METEOROLOGICAL DEPARTMENT SHIVIJI NAGAR PUNE-411005 INDIA MOBILE +919422023277 anilkumar@imdpune.gov.in [[alternative HTML version deleted]]