I would like to create a material with a remanent flux density as a function of the X coordinate in Cartesian coordinates. How do I do this? 
   	I have tried on 'Edit Material' changing the Magnetic Property to 'Spatial Linear Magnet' but it does not recognise the coordinate X or x as a parameter when I enter the function I would like to use into 'Spatial remanent flux density'. 
   	I would like to use Br = -2*X+1. 
   	  
   	Thanks!