"International Journal of Computer Mathematics" 论文

摘要

Fourier synthesis program n -2, 1, -1 or 0 respectively.A sum S m (m = 0 -3}..v may be required for / even for the formation of Si n ,' and / odd for S^+u or the reverse; in these two cases we store n = 3& -3 respectively.The arrays G, G' ,G'" are first cleared to zero and then filled with values of n.For each spacegroup, the values of g, and the associated t } are divided into p sets as described in Section 2. We number the sets 0 -{p -1) and search for pairs gr,go'+n (' *' = 0, 1, 2, 3); these occur in sets p t and p 2 .For each term tj in set p x we put G(pi, [j/2]) = 2 or 1 according as;?! = p 2 or/), # p 2 .If p, ^ p 2 then for each tj in the set p 2 , we store a value in G(p 2 , [y/2]); if this element contains 0 or -1, we store -1, but if it contains the value 1 we store 3 or -3 according as./ is odd or even.In order to fill the matrix G', for each set of g t we evaluate f = [i/2] and form the values n 0 and ti\ according to the values of V present in the set: