david-macmahon / HpguppiDatabufs.jl

HpguppiDatabufs

Live access to the shared memory buffers of an HPGUPPI DAQ process.

Installation

Both this package and HashpipeDatabufs.jl are not (yet?) in the General package registry so they must be installed from GitHub directly. This can be done using Pkg functions or using the Pkg-mode of the Julia REPL.

Using Pkg functions

using Pkg
Pkg.add("https://github.com/david-macmahon/HashpipeDatabufs.jl")
Pkg.add("https://github.com/david-macmahon/HpguppiDatabufs.jl")

Using Pkg-mode of the Julia REPL

In the Julia REPL, pressing ] at the start of the line will switch the REPL to Pkg-mode. . The prompe will change from julia> to ([env]) pkg>, where [env] is the name of the currently active environment (e.g. @v1.9).

julia> ]
(@v1.9) pkg> # Prompt changes immediately upon pressing `]`
(@v1.9) pkg> add https://github.com/david-macmahon/HashpipeDatabufs.jl
(@v1.9) pkg> add https://github.com/david-macmahon/HpguppiDatabufs.jl

Press backspace at the start of a line to switch back to the normal REPL mode.

Using HpguppiDatabufs

This package provides HPGUPPI data block structs for use with HashpipeDatabuf. The following block types are supported:

• GuppiRawBlock - A Hashpipe data block containing a GUPPI RAW header and an associated data Array. The data Array is currently presented as a Vector (i.e. a 1-dimensional Array). The user can read the header field to find the actual dimensions and reshape this Vector into a more meaningfully dimensioned Array.

• PksuwlIbvpktBlock - A Hashpipe data block that contains a sequence of VDIF packets. Instead of presenting the packets as an Array of packet structures, they are presented as three Arrays: 1. net::Vector{UInt8} - A Vector of network headers 2. vdif::Vector{UInt32} - A Vector of VDIF headers 3. data::Vector{UInt16} - A Vector of 16-bit samples

These data block structs are subtypes of HashpipeDatabufs.AbstractBlock for use with HashpipeDatabuf constuctors. Using the incorrect block type for the specified data buffer will result in incorrect interpretation of the data blocks.

To connect to an HPGUPPI databuf, simply pass the desired block type as a parameter to the contructor. For example, connecting to the first databuffer of instance 0 using PksuwlIbvpktBlock structs for the data blocks can be done like this:

julia> using HpguppiDatabufs

julia> hdb = HashpipeDatabuf{PksuwlIbvpktBlock}(0, 1)

julia> typeof(hdb.block)
Vector{PksuwlIbvpktBlock} (alias for Array{PksuwlIbvpktBlock, 1})

julia> hdb.block[1].vdif[1:3]
3-element Vector{Vector{UInt32}}:
 [0x00f4dbe7, 0x2e00c4ce, 0x20000404, 0xbc00504b, 0x00000000, 0x00000000, 0x00000000, 0xd76948a9]
 [0x00f4dbe7, 0x2e00c4cf, 0x20000404, 0xbc01504b, 0x00000000, 0x00000000, 0x00000000, 0xd7694892]
 [0x00f4dbe7, 0x2e00c4cf, 0x20000404, 0xbc00504b, 0x00000000, 0x00000000, 0x00000000, 0xd76948ab]