PCA computes PCA vectors and projects the original embeddings to the given dimension.
It returns a new slice of embeddings of the same size as the origin al embeddings,
but with the given dimension dropped to the given dimension.
TSNE calculates tsne projecion of the given embeddings into the given dimension.
It returns a new slice of embeddings of the same size as the origin al embeddings,
but with the given dimension dropped to the given dimension.