The algorithm itself takes three cost&memory values N, r, p, and if you're calling the `crypto_scrypt()` function in C or C++ as a KDF you need to specify those

The algorithm itself takes three cost&memory values N, r, p, and if you're calling the `crypto_scrypt()` function in C or C++ as a KDF you need to specify those. The command-line binary generally takes "max time" and "max ram" (as percent and/or raw value) and estimates appropriate cost values. As of version 1.3.1, you can manually specify cost values for the binary if you want.