Declaration of ESTER PIL variables
   Meanings of local variables used

   IZ0    - Location of last Z-slab in cathode 
   IZ1    - Location of Z slab under interface
   IZ2    - Location of Z slab under anodes
   IZ3    - Location of Z slab under free surface
   GDZ1   - Offset from nominal interface height at IY=1
   GDZ2   - Offset from nominal interface height at IY=NY
   DELT   - Time step for transient calculation
   MAGF   - Indicator for magnetic fields
               = 0 Take algebraic distribution
               IMAGF = 0 use PDR 20 expressions
                     = 1 use polynomial expressions
               > 0 Read field distributions from file CG(1)
                   on logical unit MAGF
   IMAGU  - Indicator for magnetic field units
              = 0 fields in Gauss -ESTRGR will convert to TESLA
              = 1 fields already in Tesla
              = 2 fields in milli-Tesla
   JZCATH - Indicator for cathode current distribution
               < 0 Take uniform value of JZCATH
               > 0 Read cathode current distribution from file CG(2)
                   on logical unit JZCATH
   IFRZ   - Indicator for freeze
               = 0 No freeze
               > 0 Read freeze locations and heights from file CG(3)
                   on logical unit IFRZ
   IANO   - Indicator for anodes
               = 0 No anodes
               > 0 Read anode loctions from file CG(4)
                   on logical unit IFRZ
   HANO   - Indicator for anode heights
               = 0 Flat anodes
               > 0 Read anode heights from file CG(5)
                   on logical unit IFRZ
   HUMP   - Indicator for interface Height
               = 0 Flat or uniformly sloped interface
               > 0 Read interface heights from file CG(6)
                   on logical unit HUMP
   RHOMET - Density of metal
   RHOELC - Density of electrolyte
   RHOANO - Density of anodes (used for flag purposes only)
   RHOFRZ - Density of freeze (used for flag purposes only)
   RHOAIR - Density of air    (used for flag purposes only)
   RHOCAT - Density of cathode
   ENUMET - Kinematic laminar viscosity of metal
   ENUELC - Kinematic laminar viscosity of electrolyte

   CONMET - Electrical conductivity of metal
   CONELC - Electrical conductivity of electrolyte
   CONFAC - Conductivity ratio for layer adjacent to anodes
   CONANO - Electrical conductivity of anodes
   CONFRZ - Electrical conductivity of freeze
   CONAIR - Electrical conductivity of air
   CONCAT - Electrical conductivity of cathode
   ANOPOT - Electric potential inside anodes
   BEMF   - Potential jump at anode-electrolyte interface
   AGRAVZ - Gravitational acceleration, g
   GMDOT  - Under-anode gas release rate in kg/m**2/s
   GPCOEF - Coefficient for gas relase at free surface
   NIH    - Sweep frequency of interface height update
   IHF    - First sweep for interface height update
   SLOH   - Slowing factor in interface height adjustment
   FDH    - Factor in interface height adjustment
   FHLIM  - Factor limiting approach of interface to anodes
   FRCON  - Factor in interface height adjustment
   RELF   - Linear relaxation factor for Lorentz force update
   DTF    - False time step for relaxation

   CONST1 - Constant in expression for Bx
   CONST2 - Constant in expression for By
   CONST3 - Constant in expression for Bz

   A0 - C7  Constants in polynomial expressions
   Declare local variables