and if the A are an inversable matrix

and  x have range=(0 to 2),the y have range = (2,3),follow when the x=(3 to 4),so the y=(3 to -3) how to implement the title's function 

still the x and y have variability value and variability number

such as the list [[0,2],[3,-2],[7,6],.....,[x,y]]

and change to piecewise