last:

i wonder how kernel get initialized in transpose convolution, such as ConvTranspose1d, ConvTranspose2d, and ConvTranspose3d. is bilinear interpolation applied to the initialization of the kernel?


Convolution layers will be initialized by default using this reset_parameters() 2 method. No interpolation is applied and the mentioned uniform sampling will be applied.



 last:

in addition, how does the kernel(filter) in the transpose convolution become learnable?
how can the kernel learn? does the kernel learn through back-propagation, like the weights in layers in transpose convolution(ConvTranspose1d, ConvTranspose2d, and ConvTranspose3d) ?


The weight parameter of the conv layers are the kernels and they will be trained as any other parameters through the backpropagation etc.