mapply in R - TypeError: '<' not supported between instances of 'list' and &#-CodePudding

I have the following dataframe that I am trying to use mapply to apply a neural network function.

learning_rate = c(0.01, 0.02) 
decay = c(0, 1e-1) 
df = expand.grid(lr = learning_rate, decay = decay)
> df
    lr decay
1 0.01   0.0
2 0.02   0.0
3 0.01   0.1
4 0.02   0.1

When I execute my function I get an error

df2 = cbind(df, mapply(LSTM_FUNC(iterations = 3, learning_rate = df$lr, decay = df$decay, epochs = 20)))


Error in py_call_impl(callable, dots$args, dots$keywords) : 
  TypeError: '<' not supported between instances of 'list' and 'int'

But, if I execute the same function just changing the arguments to hard-coded numbers everything works great. The function below works fine and it returns the RMSE and MAE

LSTM_FUNC(iterations = 3, learning_rate = 0.01, decay = 0, epochs = 20)
         avg_rmse avg_mae
    [1,]   0.5255  0.4101

The problem seems just to use df$lr and df$decay as arguments of the function and I do not understand why.

CodePudding user response：

We could do this by specifying the arguments in MoreArgs

mapply(LSTM_FUNC, learning_rate = df$lr, decay = df$decay,
    MoreArgs = list(iterations = 3, epochs = 20))

CodePudding user response：

You mistake how mapply() is used. The first argument is a function and the others are list or vector arguments to be passed into the function.

mapply(\(x, y) LSTM_FUNC(iterations = 3, learning_rate = x, decay = y, epochs = 20),
       x = df$lr, y = df$decay)