C      Compute erf(1), i.e. integral of 2/sqrt(pi) * exp(-x*x) from 0 to 1.0
C
      EXTERNAL FUNC
      REAL A,B,RESULT,ABSERR,RESABS,RESASC,PI
C
      A = 0.0
      B = 1.0
      PI = 4.0*ATAN(1.0)
      CALL QK15(FUNC,A,B,RESULT,ABSERR,RESABS,RESASC)
      WRITE(*,*) ' QK15 ESTIMATE OF ERF(1) '
      WRITE(*,*) ' 2.0/SQRT(PI)*RESULT,      ABSERR'
      WRITE(*,*) 2.0/SQRT(PI)*RESULT,ABSERR
C
      WRITE(*,*)
      WRITE(*,*) 'REFERENCE RESULTS COMPUTED ON IBM PC/AT '
      WRITE(*,*) '   0.842701       0.444360E-05    '
      STOP
      END
C      
      REAL FUNCTION FUNC(X)
        REAL X
        FUNC = EXP(-X*X)
        RETURN
      END