Simple code to calculate the magnetic field in Hyper-Kamkokande.

To build the code you will need root, but otherwise just type "make" at the command line.

Biotsavart calculation classes include:

• WireElement -- to represent a step along a wire
• typedef std::vector< WireElement > Wire -- to represent a wire
• BiotSavart -- to get magnetic field -- initialized with Wire and current

Classes specific to the calculation in HyperK include:

• HKEndCapCoils -- to build coils of wire on endcaps
• HKVerticalCoils -- to build circular coils to compensate B along z-axis
• HKHorizontalCoils -- to build box coils to compensate B along x-axis

Main code calls functions to:

• plot the magnetic field and save plots to rootfile
• do a chi^2 fit using minuit (commented out)
• do a markov-chain monte-carlo (commented out)