Virtual Accelerator

Installation

Prerequisites

It's advised to use a virtual environment, either venv or conda. Using conda is advised on the latest Mac architecture. See below for installation with conda.

Installing with pip

Installing EPICS

If you are using Linux, skip to the Installing PyORBIT step. If you are installing on a macOS, you will need to install EPICS. After installing EPICS, add the following line to your bash_profile:

export PYEPICS_LIBCA=${EPICS_BASE}/lib/${EPICS_HOST_ARCH}/libca.dylib

Installing PyORBIT

You need to have PyORBIT3 installed in the same virtual environment.

Installing Virac

The following will install the virtual accelerator in development mode, so you can edit the code and and immediately see the results without re-installation.

pip install -e .
pip list
# virtaccl should be in the list of installed packages

Alternatively, to install in isolated mode (into your site-packages).

pip install .

or even without cloning the repository

pip install git+https://URL_OF_YOUR_REPO/virtual-accelerator.git

Installing with conda

This will install EPICS, PyORBIT3, the virtual accelerator, and define the needed environment variables. You will have the standard EPICS command line tools installed as well.

conda env create -f virac.yml
conda activate virac

Run

Client environment setup

Your client environment, the one that connects to virtual accelerator, should have localhost included in CA search, so some setup may be needed.
For example, the following will ensure that the client connects to the virtual accelerator only while allowing large array transfers.

export EPICS_CA_ADDR_LIST=localhost
export EPICS_CA_AUTO_ADDR_LIST=NO
export EPICS_CA_MAX_ARRAY_BYTES=10000000

Default SNS virtual accelerator

To see help:

sns_va -h

Run default MEBT -> HEBT1

sns_va

Run MEBT only (with printing all PVs)

sns_va --debug MEBT

Run standard examples

There are two client program (they connect to VA) examples:

• Corrector.py scans SCL_Mag:DCH00 and prints out horizontal position at SCL_Diag:BPM04
• Wire.py performs a scan of MEBT_Diag:WS14 (PVs are fictional)

Both examples need VA running as a separate process (in a standalone terminla window), default virtual_accelerator command will work. To launch an example run

python -m virtaccl.examples.Corrector 

BTF beamline

To see help:

btf_va -h

Run with default bunch

btf_va --debug

BTF example file:

python -m virtaccl.examples.BTF_Mag_Test 

Hardcoded IDmp beamline of the SNS accelerator

To see help:

idmp_va -h

Run with default bunch

idmp_va --debug