data generation cluster analysis

Question

I' don't know with what R commands you can generate datasets with combination of parameters (dimension, cluster proportions,model). I use this commands

formmatrix = function(a,b,c,d,e,f,p){
   m1 = c(0,8,rep(0, p-2))
   m2 = c(8,0,rep(0, p-2))
   m3 = c(-8,-8,rep(0, p-2))
   
   sig1 = diag(c(1,a, rep(1, p-2)))
   sig2 = diag(c(b,c, rep(1, p-2)))
   sig3 = matrix(c(d,e,e,f),2,2,byrow=T)
   sig3 = cbind(sig3, matrix(rep(0,2*(p-2)),2))
   sig3 = rbind(sig3, cbind(t(matrix(rep(0,2*(p-2)),2)), diag(rep(1, p-2))))
   
   return(list(m1=m1, m2=m2, m3=m3, sig1=sig1, sig2=sig2, sig3=sig3))
 }
 p = 2
 sim1 = formmatrix(1,1,1,1,0,1, p)
 sim2 = formmatrix(5,1,5,1,0,5, p)
 sim3 = formmatrix(5,5,1,3,-2,3, p)
 sim4 = formmatrix(1,20,5,15,-10,15, p)
 sim5 = formmatrix(1, 45, 30, 15, -10, 15, p)
 
mixt1 <- rbind(rmvnorm(200, mean = sim1$m1, sigma = sim1$sig1),
              rmvnorm(300, mean = sim1$m2 ,sigma = sim1$sig2 ),
            rmvnorm(500, mean = sim1$m3,sigma = sim1$sig3))