Hi list, Is any body has implemented the projection pursuit regression (ppr) method in MASS library.Running the ppr method is not a problem , But problem is how we are getting the model parameters using least square method ,becoz the function is looking like a continous function and how a continous function can be found out by least square method....THat function name is ridge function (activation function ) If any body is having idia please ,reply its very urgent,,,,,,,,becoz of this problem i am not able to proceed for my paper ,. ANy help is much appriciated 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]]