module: dsynth_mux4
parameters: 
inputs: double in0, double in1, double in2, double in3,double sel 
outputs:  double y
static_variables:  
classes:
init: 
code:
if(-0.5<=sel&&sel<0.5) y=in0;
else if(0.5<=sel&&sel<1.5) y=in1;
else if(1.5<=sel&&sel<2.5) y=in2;
else if(2.5<=sel&&sel<3.5) y=in3;
