Laguerre weight function
y=laguerre_weight(x)
a matrix of doubles
a matrix of doubles, the weight
Computes the Exponential weight function:
for x positive.
x=linspace(0,4,1000); y=laguerre_weight(x); scf(); plot(x,y) xtitle("Laguerre weight","x","w(x)") // Check integral : must be 1. v=intg(0,10,laguerre_weight)