polynomial kernel, d=2, c=1

[yamauchilab]

polynomial kernel of Rdimtools and kernlab return different values. Isn't this a bug?

e.g.,

(x = matrix(c(1:6), 2, 3))

 [,1] [,2] [,3]

[1,] 1 3 5
[2,] 2 4 6

library(Rdimtools)
(x_kpoly_Rdim_d2 = aux.kernelcov(x, ktype = c("polynomial", d=2, c=1)))

$K
[,1] [,2]
[1,] 37 46
[2,] 46 58

$Kcenter
[,1] [,2]
[1,] 0.75 -0.75
[2,] -0.75 0.75

library(kernlab)
linear_kern <- polydot(degree = 2, scale = 1, offset=1)
(x_kpoly_d2_kernlab = kernelMatrix(kernel = linear_kern, x=x))

An object of class "kernelMatrix"
[,1] [,2]
[1,] 1296 2025
[2,] 2025 3249

[kisungyou]

@yamauchilab thanks for your input. The aux.kernelcov takes a parameter in ktype in order, not by assigning in a vector. Hence, in this case, you should use ktype=c("polynomial",1,2) in an order of the parameters as described.

[yamauchilab]

Oh, I am so sorry. That was my careless mistake. Takashi

…

On Wed, Apr 5, 2023 at 10:33 AM Kisung You ***@***.***> wrote: @yamauchilab thanks for your input. The aux. kernelcov takes a parameter in ktype in order, not by assigning in a vector. Hence, in this case, you should use ktype=c("polynomial",1,2) in an order of the parameters as described. —Reply ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization. ZjQcmQRYFpfptBannerEnd @yamauchilab <https://urldefense.com/v3/__https://github.com/yamauchilab__;!!KwNVnqRv!FKZsnKFcyObWtcfMgyPDtFiMcUJEUWqyWNiYiGaq4gQSn6TxSYe1Ml-kG6GFWZTHGpnbSgkO95bG0pMm2JcYmIZAA7A_e1-1$> thanks for your input. The aux.kernelcov takes a parameter in ktype in order, not by assigning in a vector. Hence, in this case, you should use ktype=c("polynomial",1,2) in an order of the parameters as described. — Reply to this email directly, view it on GitHub <https://urldefense.com/v3/__https://github.com/kisungyou/Rdimtools/issues/17*issuecomment-1497691821__;Iw!!KwNVnqRv!FKZsnKFcyObWtcfMgyPDtFiMcUJEUWqyWNiYiGaq4gQSn6TxSYe1Ml-kG6GFWZTHGpnbSgkO95bG0pMm2JcYmIZAA_33wtV0$>, or unsubscribe <https://urldefense.com/v3/__https://github.com/notifications/unsubscribe-auth/AMJB6PCXRFBAU7LDSGW6YRLW7WGF5ANCNFSM6AAAAAAWTEIRUQ__;!!KwNVnqRv!FKZsnKFcyObWtcfMgyPDtFiMcUJEUWqyWNiYiGaq4gQSn6TxSYe1Ml-kG6GFWZTHGpnbSgkO95bG0pMm2JcYmIZAA_Zs2kuz$> . You are receiving this because you were mentioned.Message ID: ***@***.***>