(@v1.10) pkg> add BlockDiagonals
Updating registry at `C:\Users\jmzhang\.julia\registries\General.toml`
Resolving package versions...
Installed FiniteDifferences ─ v0.12.31
Installed Richardson ──────── v1.4.2
Cloning [0a1fb500-61f7-11e9-3c65-f5ef3456f9f0] BlockDiagonals from https://github.com/JuliaArrays/BlockDiagonals.jl
ERROR: failed to clone from https://github.com/JuliaArrays/BlockDiagonals.jl, error: GitError(Code:ERROR, Class:SSL, Your Julia is built with a SSL/TLS engine that libgit2 doesn't know how to configure to use a file or directory of certificate authority roots, but your environment specifies one via the SSL_CERT_FILE variable. If you believe your system's root certificates are safe to use, you can `export JULIA_SSL_CA_ROOTS_PATH=""` in your environment to use those instead.)
感觉julia安装包很麻烦啊，大部分时候都不成功。