c
c  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
c  .                                                             .
c  .                  copyright (c) 1998 by UCAR                 .
c  .                                                             .
c  .       University Corporation for Atmospheric Research       .
c  .                                                             .
c  .                      all rights reserved                    .
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c  .                                                             .
c  .                         SPHEREPACK                          .
c  .                                                             .
c  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
c
c
c      subroutine gaqd(nlat,theta,wts,w,lwork,ierror)
c
c  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
c  .                                                             .
c  .                  copyright (c) 2001 by ucar                 .
c  .                                                             .
c  .       university corporation for atmospheric research       .
c  .                                                             .
c  .                      all rights reserved                    .
c  .                                                             .
c  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
c
c                             August 2003
c                        
c     gauss points and weights are computed using the fourier-newton
c     described in "on computing the points and weights for 
c     gauss-legendre quadrature", paul n. swarztrauber, siam journal 
c     on scientific computing, 24(2002) pp.945-954.
c     This routine is faster and more accurate than older program 
c     with the same name.
c
c     a test program is located in file tgaqd.f
c
c     subroutine gaqd computes the nlat gaussian colatitudes and weights
c     in double precision. the colatitudes are in radians and lie in the
c     in the interval (0,pi).
c
c     input parameters
c
c     nlat    the number of gaussian colatitudes in the interval (0,pi)
c             (between the two poles).  nlat must be greater than zero.
c
c     w       unused double precision variable that permits a simple 
c             exchange with the old routine with the same name in 
c             spherepack.
c
c     lwork   unused variable that permits a simple exchange with the
c             old routine with the same name in spherepack.
c
c     output parameters
c
c     theta   a double precision array with length nlat
c             containing the gaussian colatitudes in
c             increasing radians on the interval (0,pi).
c
c     wts     a double precision array with lenght nlat
c             containing the gaussian weights.
c
c     ierror = 0 no errors
c            = 1 if nlat.le.0
c