I'm using gfortran on SUSE to compile my code and receive the following error:

Code:

```
yr_step = sign(1,delta_yr)
1
Error: 'b' argument of 'sign' intrinsic at (1) must be the same type and kind as 'a'
```

Here's my code:

Code:

```
subroutine solar_loc(yr,t1,mean_long,declination)
implicit none
integer*2 yr,yr_step,delta_yr,i,iyr
integer*4 t1
integer*4 index
real*4 mean_long,declination
real*8 d,lambda,g,eps,L
real*8 L0(10)/279.642,279.403,279.165,278.926,279.673,279.434,
1 279.196,278.957,279.704,279.465/
real*8 DL/0.985647/
real*8 G0(10)/356.892984,356.637087,356.381191,356.125295,
1 356.854999,356.599102,356.343206,356.087308,356.817011,356.56/
real*8 DG/0.98560028/
real*8 EPS0(10)/23.440722,23.440592,23.440462,23.440332,
1 23.440202,23.440072,23.439942,23.439811,23.439679,23.439548/
real*8 DE/-0.00000036/
real sind,asind
save
d = 0
if (yr .lt. 1900) then
index = yr - 88
else
index = yr - 1988
endif
if (index .le. 0) then
delta_yr = index - 1
else if (index .gt. 10) then
delta_yr = index - 10
else
delta_yr = 0
endif
if (index .le. 0) index = 1
if (index .gt. 10) index = 10
yr_step = sign(1,delta_yr)
delta_yr = abs(delta_yr)
do i = 1,delta_yr
if (yr_step .gt. 0) then
iyr = 98 + i - 1
else
iyr = 89 - i
end if
if (mod(iyr,4).eq.0)then
d = d + 366*yr_step
else
d = d + 365*yr_step
end if
end do
d = d + t1/86400.
L = L0(index) + DL*d
g = G0(index) + DG*d
do while (L.lt.0)
L = L + 360.
end do
do while (g.lt.0)
g = g + 360.
end do
L = mod(L,360.0d0)
g = mod(g,360.0d0)
lambda = L + 1.915*sind(g) + 0.020*sind(2*g)
eps = EPS0(index) + DE*d
declination = asind(sind(eps)*sind(lambda))
mean_long = L
return
end
```

Any suggestions? Thanks in advance!