!·ûºÅº¯Êý
    real*8 function FUNC_sign(A)
    implicit none
    
    real*8 :: A
    if(isnan(A)) then
        FUNC_sign = sqrt(-1.0)
    elseif(A>0) then
        FUNC_sign = 1.0
    elseif(A<0) then
        FUNC_sign = -1.0
    elseif(A==0) then
        FUNC_sign = 0.0
    end if
    
    end function