mrphy.__init__

A MRI excitation physics module.

About MRphy.py:

MRphy.py provides the following constant and submodules:

Constant:

• γH: water proton gyro frequency, “4257.6 Hz/Gauss”.

Submodules:

• utils

• beffective

• sims

• slowsims

• mobjs

General Comments:

Variable naming convention:

A trailing _ in a variable/attribute name indicates compactness, i.e. instead of size (N, *Nd, ...), the variable/attributes size (N, nM, ...). For instance: A field map variable Δf may be of size (N, nx, ny, nz), while its compact countarpart Δf_ has a size of (N, nM).

Special keywords used in documentations:

• N: batch size

• nM: the number of spins

• Nd: A int-tuple for array size, e.g.: Nd = (nx, (ny, (nz))). In python convention, * unpacks a tuple. Therefore, (N, *Nd) === (N, nx, ny, nz).

• nT: the number of time points

• xy: the dimension has length of 2

• xyz: the dimension has length of 3

• ⊻: Either or. When used in enumerating function keywords arguments, it means the function accepts at most one of the keywords in a set as an input, e.g., Δf ⊻ Δf_ means accepting either Δf or Δf_. When used in specifying variable dimensions, it means the dimension tuple can be one of the size tuple set, e.g. (N, nM ⊻ *Nd, xyz) means accepting dimension either (N, nM, xyz) or (N, *Nd, xyz).