C GQUAD     SOURCE    CHAT      05/01/13    00:19:19     5004           
      FUNCTION GQUAD(F,A,B,N)                                                   
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8(A-H,O-Z)                                                  
      EXTERNAL F                                                                
      DIMENSION X(1),W(1)                                                       
C                                                                               
C     ******************************************************************        
C                                                                               
C     GQUAD IS SET EQUAL TO THE INTEGRAL OF THE FUNCTION F OVER THE IN-         
C     TERVAL (A,B), AS APPROXIMATED BY THE GAUSS-LEGENDRE QUADRATURE            
C     FORMULA OF ORDER N.                                                       
C                                                                               
C     CALLS ... SUBROUTINE D106XX.                                              
C                                                                               
C     ******************************************************************        
C                                                                               
      CALL D106XX(1,F,A,B,N,X,W)                                                
      GQUAD=X(1)                                                                
      RETURN                                                                    
      END