R 一起绘制几个热图

我正在使用

pheatmap

package在R中绘制热图。我想使用这个软件包一起绘制几个热图。例如，通过这样做：

 library(pheatmap)
    test = matrix(rnorm(200), 20, 10)
test[1:10, seq(1, 10, 2)] = test[1:10, seq(1, 10, 2)] + 3
test[11:20, seq(2, 10, 2)] = test[11:20, seq(2, 10, 2)] + 2
test[15:20, seq(2, 10, 2)] = test[15:20, seq(2, 10, 2)] + 4
colnames(test) = paste("Test", 1:10, sep = "")
rownames(test) = paste("Gene", 1:20, sep = "")


p1 = pheatmap(test, name = "mat1")
p2 = pheatmap(test, name = "mat2", 
              col = colorRampPalette(c("navy", "white", "firebrick3"))(50))
# or you can simply specify as
# p3 = pheatmap(test, name = "mat2", col = c("navy", "white", "firebrick3"))
p1 + p2 

我一直收到以下错误消息：

Error in p1 + p2 : argument non numérique pour un opérateur binaire

有没有办法做到这一点