a = matrix(c(3,5,6,2,1,9,8,7,4),3,3)
b = matrix(c(1,2,3,4,5,6,7,8,9),3,3,byrow = T)

##把a矩阵按行从大到小排列，则每行的元素排序矩阵 id_matrix为:
id_matrix = apply(a,1,function(x) order(x,decreasing = T))
##此时该矩阵的每一列对应矩阵a每一行元素的排序
##矩阵b对应变动后，形成的新矩阵b_new:
b_new = c()
for(i in 1:nrow(b)){
b_new= rbind(b_new,b[i,][id_matrix[,i]])
}