Type DependendSymbol

object --+    
         |    
    Symbol --+
             |
            DependendSymbol

Known Subclasses:

Abs_Symbol, Acos_Symbol, Acosh_Symbol, Add_Symbol, Asin_Symbol, Asinh_Symbol, Atan_Symbol, Atanh_Symbol, Cos_Symbol, Cosh_Symbol, Exp_Symbol, GeneralTensorProduct_Symbol, GetSlice_Symbol, Grad_Symbol, Integrate_Symbol, Interpolate_Symbol, Inverse_Symbol, Log_Symbol, Maxval_Symbol, Minval_Symbol, Mult_Symbol, Power_Symbol, Quotient_Symbol, Sin_Symbol, Sinh_Symbol, Sqrt_Symbol, Tan_Symbol, Tanh_Symbol, Trace_Symbol, Transpose_Symbol, WhereNegative_Symbol, WherePositive_Symbol, WhereZero_Symbol

DependendSymbol extents L{Symbol} by modifying the == operator to allow two instances to be equal. 
Two DependendSymbol are equal if they have the same shape, the same arguments and one of them has an unspecified spatial dimension or the spatial dimension is identical  

Example: 

u1=Symbol(shape=(3,4),dim=2,args=[4.])
u2=Symbol(shape=(3,4),dim=2,args=[4.])
print u1==u2
False

   but   

u1=DependendSymbol(shape=(3,4),dim=2,args=[4.])
u2=DependendSymbol(shape=(3,4),dim=2,args=[4.])
u3=DependendSymbol(shape=(2,),dim=2,args=[4.])   
print u1==u2, u1==u3
True False

@note: DependendSymbol should be used as return value of functions with L{Symbol} arguments. This will allow the optimizer to remove redundant function calls.