The Sarkar algorithm used in the Pasta implementation is applicable to Fq since it is highly 2-adic. (Fr is not, but optimizing Fq square roots is more important for Jubjub curve point decompression, and therefore for Sapling trial decryption; see https://github.com/zcash/librustzcash/pull/423#issuecomment-894377882 ).
Suggested by @str4d:
The Sarkar algorithm used in the Pasta implementation is applicable to
Fq
since it is highly 2-adic. (Fr
is not, but optimizingFq
square roots is more important for Jubjub curve point decompression, and therefore for Sapling trial decryption; see https://github.com/zcash/librustzcash/pull/423#issuecomment-894377882 ).