
 NIT WILL PROMPT YOU WITH QUESTIONS. ANSWER THEM BY TYPING THE
 NUMBER OF THE CORRECT ANSWER FOLLOWED BY A CARRIAGE RETURN.

 IN ADDITION, THE FOLLOWING RESPONSES MAY
 BE TYPED AT ANY TIME:
     B FOR BEGINNING A NIT SESSION AGAIN
     P FOR MOVING TO THE PREVIOUS QUESTION
     Q FOR QUITTING A NIT SESSION IMMEDIATELY
     ? OR H FOR HELP
     S FOR MAKING SUGGESTIONS
     J FOR A DYNAMIC GOTO
     N TO SEE THIS MESSAGE

 NIT TREES-SELECT FROM: 
  (1) CURVE AND SURFACE FITTING
  (2) PARTIAL DIFFERENTIAL EQUATIONS
 *

 WHAT TYPE OF FUNCTION DO YOU WISH TO USE FOR THE APPROXIMATION? 
  (1) POLYNOMIALS OR SPLINES  
  (2) OTHER   
 *
 
 DO THE COEFFICIENTES IN THE APPROXIMATION OCCUR LINEARLY,
 I.E. IN THE REQUIRED APPROXIMATION OF THE FORM
      C1*P1(X)+C2*P2(X)+C3*P3(X)+ . . . +CN*PN(X)
 WHERE X IS A VECTOR OF ONE OR MORE INDEPENDENT VARIABLES,
 THE PI(X) ARE GIVEN FUNCTIONS OF THESE VARIABLES,
 AND C1,C2,...,CN ARE THE COEFFICIENTS TO BE COMPUTED?
  (1) NO  
  (2) YES 
 *
 
 YOU CAN CHOOSE BETWEEN THESE NORMS, I.E.
   L1 NORM - MINIMIZE THE SUM OF THE ABSOLUTE ERRORS (USEFUL WHEN THE
             DATA CONTAINS SOME LARGE ERRORS)
   L2 NORM - MINIMIZE THE SUM OF THE SQUARES OF THE ERRORS
   LINF NORM - MINIMIZE THE MAXIMUM ABSOLUTE ERROR (USEFUL WHEN THE
               DATA CONTAINS ONLY SMALL INHERENT ERRORS)
 CHOOSE FROM:

 ** END OF TEXT, TYPE A CARRIAGE RETURN TO CONTINUE ** 
  (1) L2 NORM 
  (2) DON'T KNOW  
  (3) L1 NORM 
  (4) LINF NORM   
 *

 USE E02GCF  
  (1) NAG DOCUMENTATION?  
  (2) MORE INFORMATION?   
 *
 
 FOR WHICH COMPUTER DO YOU WISH INFORMATION ABOUT THIS ROUTINE?
 CHOOSE FROM:
  (1) NONE
  (2) FED DEC PDP-10  
  (3) X-10 DEC PDP-10 
  (4) X-10 IBM 3033   
  (5) NMFECC CRAY-1   
 *

 DO YOU WISH TO USE SINGLE OR DOUBLE PRECISION?  
  (1) SINGLE PRECISION
  (2) DOUBLE PRECISION
 *

 NIT EXECUTION NORMAL, NO ERRORS ENCOUNTERED
