function filesave( fname , prec , data )

# kiss fft stores data by rows
data = vec(data.');

len = length(data);

f = fopen(fname,"w", "native");

if is_complex(data),
    flat=zeros( 1,2*len);
    flat(1:2:2*len) = real(data);
    flat(2:2:2*len) = imag(data);
    data = flat;
endif

fwrite(f,data,prec);
fclose(f);

endfunction