在 R 中的 SVM 模型中看不到 gamma 参数

Question

我正在尝试使用线性内核在 iris 数据集上拟合 SVM 模型（e1071 包）。模型拟合成功，但摘要（模型）调用中只有'SVM-Type'，'SVM-Kernel'和'cost'参数，看不到gamma参数。

#load iris data
data(iris) 
head(iris)
table(iris$Species)
iris = iris[,c(3:5)]
str(iris)
model = svm(Species~.,data = iris, kernel = "linear")
summary(model)

data(iris) #load iris data
head(iris)
  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa
3          4.7         3.2          1.3         0.2  setosa
4          4.6         3.1          1.5         0.2  setosa
5          5.0         3.6          1.4         0.2  setosa
6          5.4         3.9          1.7         0.4  setosa
table(iris$Species)

    setosa versicolor  virginica 
        50         50         50 
iris = iris[,c(3:5)]
str(iris)
'data.frame':   150 obs. of  3 variables:
 $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
 $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
 $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
model = svm(Species~.,data = iris, kernel = "linear")
summary(model)

Call:
svm(formula = Species ~ ., data = iris, kernel = "linear")


Parameters:
   SVM-Type:  C-classification 
 SVM-Kernel:  linear 
       cost:  1 

Number of Support Vectors:  31

 ( 3 15 13 )


Number of Classes:  3 

Levels: 
 setosa versicolor virginica

我怎样才能在摘要（模型）调用中看到伽玛参数？？请需要帮助。