Error: FFTSG

[Ross, Sun]

Hi all,
I used ''FFTSG LIBRARY'' and ''WAVELET'' to calculated the electron
density of a slab (PERIODIC XZ; lattice: ABC 10.089 25.0 10.089). And
the code gives the following error, could anyone tell me how to deal
with it? Thanks a lot.

------------------------------------------------------------------------
 Value of     2 not allowed for fft, allowed values are:
    3    4    5    6    8    9   12   15   16   18   20   24   25
27   30
   32   36   40   45   48   54   60   64   72   75   80   81   90
96  100
  108  120  125  128  135  144  150  160  162  180  192  200  216
225  240  243  256  270  288  300  320  324  360  375  384  400  405
432  450  480  486  500  512  540  576  600  625  640  648  675  720
729  750  768  800  810  864  900  960  972 1000 1024
------------------------------------------------------------------------

BTW, is it suitable using FFTW LIBRARY instead to calculated the
electron density of a slab?

Best regards,