remove references to COCOS 0,10

While technically accepted by GRAY, these indices do not carry a special
meaning, as wrongly implied by the documentation: they are equivalent
to 8, 18 and specifically don't change the meaning of sgnbi,sgni.

doc/3.io-files.md

@@ -350,18 +350,15 @@ Variable         Type          Units          Valid range       Definition
                                                                   2=none (`ab`=0).
 
 `filenmprf`      String                     len$(s) ≤ 24$       Name of file for kinetic profiles
-                                                                (extension `.prf` appended).
 
 `psdbnd`         Real        1              $x > 0$             Normalized psi value at the plasma boundary where
                                                                 $n_e$ is set to zero (typ. $1 ≤ {\tt psdbnd} ≤ 1.1$).
 
-`sgnbphi`        Real        1              -1, +1              Signum of toroidal B, used if `icocos`=0.
+`sgnbphi`        Real        1              -1, +1, 0           Force signum of toroidal B, used if nonzero
 
-`sgniphi`        Real        1              -1, +1              Signum of toroidal plasma current $I$, used if `icocos`=0.
+`sgniphi`        Real        1              -1, +1, 0           Force Signum of toroidal plasma current $I$, used if nonzero
 
-`icocos`         Int                        0-8, 10-18          COCOS index used in `filenmeqq` as defined in [@cocos]:
-                                                                0=no COCOS convention and psi in Wb/rad,
-                                                                10=means no convention and psi in Wb.
+`icocos`         Int                        1-8, 11-18          COCOS index used in the EQDSK equilibrium as defined in [@cocos]:
 ----------------------------------------------------------------------------------------------------------------------------
 
 Table: GRAY input data `gray_params.data` - plasma data {#tbl:input2}

input/gray.ini

@@ -92,8 +92,8 @@ iequil = EQ_EQDSK_FULL
 
 ; Filepath of the equilibrium data (relative to this file)
 filenm = "magneticdata.eqdsk"
-; COCOS index
-icocos = 0
+; COCOS index of the EQDSK equilibrium
+icocos = 7
 
 ; Whether the poloidal function is normalised (G-EQDSK)
 ;   false: is not normalised, ψ → |ψ - ψ(edge)|/|ψ(axis) - ψ(edge)|
@@ -119,8 +119,11 @@ ixp = X_IS_MISSING
 ssplps = 0.005  ; for ψ(R,Z), normalised poloidal flux
 ssplf = 0.01    ; for F(ψ)=R⋅B_T, poloidal current function
 
-; Sign of toroidal field/current (used when COCOS index is 0,10)
-; When viewing from above: +1 → counter-clockwise, -1 → clockwise
+; Force the sign of toroidal field/plasma current
+; When viewing from above:
+;   +1 → counter-clockwise
+;   -1 → clockwise
+;    0 → use sign from COCOS
 sgnb = -1
 sgni = +1
 ; Rescaling factor for the magnetic field

input/gray_params.data

@@ -13,7 +13,7 @@ beam.data        x filename for beam data
 
 2                x iequil= 0 vacuum, 1 analytical equilibrium, 2 EQDSK
 equiln.txt       x filename for equilibrium
-11 0  1 0        x icocos [=0..8,10..18], ipsinorm =0/1 [psi normalized (1) or not (0) in EQDSK], idesc =0/1, ifreefmt= 0/1
+11 0  1 0        x icocos [=1..8,11..18], ipsinorm =0/1 [psi normalized (1) or not (0) in EQDSK], idesc =0/1, ifreefmt= 0/1
 0  0.005  0.01   : indXpoint, sspl spline coeff psi, ssplf spline coeff fpol
 -1 -1  1         x signum B_phi I_phi +1=counterclockwise , -1=clockwise from above, factb
 

src/equilibrium.f90

@@ -385,8 +385,8 @@ contains
         data%psia = data%psia * params%factb
         data%fpol = data%fpol * params%factb
 
-        ! Compute the signs to be shown in the outputs header when cocos≠0,10.
-        ! Note: In these cases the values sgni,sgnb from gray.ini are unused.
+        ! Compute the signs to be shown in the outputs header
+        ! Note: this is needed if sgni, sgnb = 0 in gray.ini
         params%sgni = int(sign(one, -data%psia))
         params%sgnb = int(sign(one, +data%fpol(size(data%fpol))))
     end select