Honeybee: Slow-Controls Data Access Library in C++

Purposes:

• Pandas-like interface to Dripline SQL data
• Managed sensor names in multiple data sources
• Managed channel mappings that can evolve
• Managed retrospective calibrations
• Zero startup overhead (convention over configuration rule)

Installation

Prerequisite

PostgreSQL System-wide

• postgresql-server-dev-all
• libpq-dev

Compiling

This library consists of two sub-modules (external libraries, written by Sanshiro and publicly available) and one main module:

• Honeybee: main module
• Kebap: formula evaluator
• Tabree: table and tree of variants, JSON I/O, SQL result structure

The usual CMake procedure can be used to install these all (Method 1). Alternatively, for the default installation configuration, a shell script can be used for convenience (Method 2, recommended).

Method 1 (standard CMake procedure)

1. go to honeybee/src/ExternalLibraries
2. do the usual CMake procedure: cmake, make and make install
3. add the INSTALL_DIR/lib/cmake to the CMake package path (CMAKE_PREFIX_PATH etc)
4. go to honeybee/src/Honeybee
5. do the usual CMake procedure

Method 2 (installation shell script for default configuration)

A shell script is provided to do the Method 1 procedure with the default configuration:

• the build directories are honeybee/src/build-extern and honeybee/src/build-honeybee
• the install directory is honeybee/install

Nothing will be placed outside the honeybee tree and no environmental variable is automatically set.

$ cd honeybee/src
$ ./setup-honeybee.sh 
Honeybee will be installed at  /home/sanshiro/workspace/Project8/honeybee/install
Are you sure? [y/N] y
-- The CXX compiler identification is Clang 6.0.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done

• The executable files are located at honeybee/install/bin
• The CMake files (necessary to use honeybee) are located at honeybee/install/lib/cmake

Usage

Database Connection

PostgreSQL for ATD at UW:

• IP: currently 10.0.0.31, will be changed to 10.0.4.x
• Port: 5432
• Database: p8_sc_db
• User: p8_db_user
• Password: **** (should be the same as phase-II)

Setup a ssh tunnel using your account on the p8-potal (128.208.127.109):

$ ssh -f -N -L 5432:10.0.0.31:5432 128.208.127.109

Test the connection:

$ psql -U p8_db_user -d p8_sc_db -h localhost
Password for user p8_db_user: ****
Type "help" for help.

p8_sc_db=> select * from numeric_data order by timestamp desc limit 10;
   endpoint_name    |           timestamp           |  value_raw   | value_cal | memo 
--------------------+-------------------------------+--------------+-----------+------
 degC_RTD7_Acc_AS   | 2022-04-19 08:04:56.761709+00 |      -242.02 |           | 
 mbar_CC10_Inj_Gas  | 2022-04-19 08:04:56.735714+00 |         1095 |           | 
 V_CC10_Inj_Gas     | 2022-04-19 08:04:56.729207+00 |       4.8734 |           | 
 degC_RTD6_Acc_AS   | 2022-04-19 08:04:56.631642+00 |      -242.02 |           | 
 degC_RTD5_Acc_AS   | 2022-04-19 08:04:56.487037+00 |      -242.02 |           | 
 degC_RTD4_Acc_AS   | 2022-04-19 08:04:56.348033+00 |      -242.02 |           | 
 degC_RTD3_Acc_AS   | 2022-04-19 08:04:56.216482+00 |      -242.02 |           | 
 V_ThermoCo_Diss_AS | 2022-04-19 08:04:56.086349+00 | 0.0001086677 |           | 
 degC_RTD2_Acc_AS   | 2022-04-19 08:04:56.082338+00 |      -242.02 |           | 
 degC_RTD1_Acc_AS   | 2022-04-19 08:04:55.948071+00 |      -242.02 |           | 
(10 rows)

Quick Tour

Sensor Table and Management of Sensor Channels

Sensors are organized in a tree structure, and the configuration is typically described in a config file. For the ATD at UW (ATDS) setup, the file is honeybee/SensorTable/SensorTable_ATDS.ktf:

# data_sources:
#  dripline_psql:
#    uri: p8_db_user:****@localhost:5432/p8_sc_db
#    basename: ATDS

# sensor_table:
#   setup:
#     id: { name: ATDS, label: Atomic Tritium Demonstrator in Seattle }
#     valid_if: date > 20201001

#     section:
#       id: { name: Gas, label: Gas Handling }
#       subsection:
#         id: { name: Inj, label: Injection }
#         module:
#           id: { name: Alicat, label: Alicat Flowmeter }
#           channel:
#             id: { name: sccm, label: Flow }
#           channel:
#             id: { name: degC, label: Temperature }
#           channel:
#             id: { name: psia, label: Pressure }
#         module:
#           id: { name: CC10, label: CC10 Pressure Gauge }
#           channel:
#             id: { name: V, label: LabJunk Voltage }
#           channel:
#             id: { name: mbar, label: Pressure }

#     section:
#       id: { name: AS, label: Atomic Source }
#       subsection:
#         id: { name: Diss, label: Dissociator }
#         module:
#           id: { name: Sys, label: Dissociator System }
..... (continues)

(here the format is very similar to YAML, but not exactly the same: multiple child nodes of the same tag name construct an array. This format will be / can be replaced with YAML.)

The sensors defined in the config file can be viewed by the install/bin/hb-list-sensors command:

$ ./install/bin/hb-list-sensors --config=SensorTable/SensorTable_ATDS.ktf 
[
    { "number": 268435456, "name": "sccm.Alicat.Inj.Gas.ATDS", "options": { "dripline_endpoint": "sccm_Alicat_Inj_Gas" } },
    { "number": 268435457, "name": "degC.Alicat.Inj.Gas.ATDS", "options": { "dripline_endpoint": "degC_Alicat_Inj_Gas" } },
    { "number": 268435458, "name": "psia.Alicat.Inj.Gas.ATDS", "options": { "dripline_endpoint": "psia_Alicat_Inj_Gas" } },
    { "number": 268435459, "name": "V.CC10.Inj.Gas.ATDS", "options": { "dripline_endpoint": "V_CC10_Inj_Gas" } },
    { "number": 268435460, "name": "mbar.CC10.Inj.Gas.ATDS", "options": { "dripline_endpoint": "mbar_CC10_Inj_Gas" } },
    { "number": 268435461, "name": "Type.Sys.Diss.AS.ATDS" },
    { "number": 268435462, "name": "V.PS.Diss.AS.ATDS", "options": { "dripline_endpoint": "V_PS_Diss_AS" } },
    { "number": 268435463, "name": "A.PS.Diss.AS.ATDS", "options": { "dripline_endpoint": "A_PS_Diss_AS" } },
    { "number": 268435464, "name": "V.ThrmCpl.Diss.AS.ATDS", "options": { "dripline_endpoint": "V_ThermoCo_Diss_AS" } },
    { "number": 268435465, "name": "degC.ThrmCpl.Diss.AS.ATDS", "default_calibration": "V:5.1865e-01+V*(-7.0934e+04+V*(-2.4686e+06+V*(-1.3643e+08+V*(-3.3825e+09+V*(-3.5836e+10)))))" },
    { "number": 268435466, "name": "K.ThrmCpl.Diss.AS.ATDS", "default_calibration": "degC:degC+273.15" },
    { "number": 268435467, "name": "degC.RTD0.Acc.AS.ATDS" },
    { "number": 268435468, "name": "K.RTD0.Acc.AS.ATDS", "default_calibration": "degC:degC+273.15" },
    { "number": 268435469, "name": "degC.RTD1.Acc.AS.ATDS", "options": { "dripline_endpoint": "degC_RTD1_Acc_AS" } },
    { "number": 268435470, "name": "K.RTD1.Acc.AS.ATDS", "default_calibration": "degC:degC+273.15" },
    { "number": 268435471, "name": "degC.RTD2.Acc.AS.ATDS", "options": { "dripline_endpoint": "degC_RTD2_Acc_AS" } },
    { "number": 268435472, "name": "K.RTD2.Acc.AS.ATDS", "default_calibration": "degC:degC+273.15" },
..... (continues)

The sensor list can be filtered by providing (partial) name matches:

### all sensors in the "Diss.AS" section ###
$ ./install/bin/hb-list-sensors  --config=SensorTable/SensorTable_ATDS.ktf   Diss.AS
[
    { "number": 268435461, "name": "Type.Sys.Diss.AS.ATDS" },
    { "number": 268435462, "name": "V.PS.Diss.AS.ATDS", "options": { "dripline_endpoint": "V_PS_Diss_AS" } },
    { "number": 268435463, "name": "A.PS.Diss.AS.ATDS", "options": { "dripline_endpoint": "A_PS_Diss_AS" } },
    { "number": 268435464, "name": "V.ThrmCpl.Diss.AS.ATDS", "options": { "dripline_endpoint": "V_ThermoCo_Diss_AS" } },
    { "number": 268435465, "name": "degC.ThrmCpl.Diss.AS.ATDS", "default_calibration": "V:5.1865e-01+V*(-7.0934e+04+V*(-2.4686e+06+V*(-1.3643e+08+V*(-3.3825e+09+V*(-3.5836e+10)))))" },
    { "number": 268435466, "name": "K.ThrmCpl.Diss.AS.ATDS", "default_calibration": "degC:degC+273.15" }
]

### all sensors that have "mbar" reading ###
$ ./install/bin/hb-list-sensors  --config=SensorTable/SensorTable_ATDS.ktf   mbar    
[
    { "number": 268435460, "name": "mbar.CC10.Inj.Gas.ATDS", "options": { "dripline_endpoint": "mbar_CC10_Inj_Gas" } },
    { "number": 268435491, "name": "mbar.IG.Vac.AS.ATDS", "options": { "dripline_endpoint": "mbar_IG_Vac_AS" } },
    { "number": 268435503, "name": "mbar.IG.Vac.VSS.ATDS", "options": { "dripline_endpoint": "mbar_IG_Vac_VSS" } },
    { "number": 268435606, "name": "mbar.IG.Vac.MS.ATDS", "options": { "dripline_endpoint": "mbar_IG_Vac_MS" } }
]

The sensor table can be constructed from Dripline data, instead of or in addition to configuration files:

$ ./install/bin/hb-list-sensors  --dripline-db=p8_db_user:****@localhost:5432/p8_sc_db
[
    { "number": 268435456, "name": "degC.RTD2.Acc.AS", "options": { "dripline_endpoint": "degC_RTD2_Acc_AS" } },
    { "number": 268435457, "name": "mbar.CC10.Inj.Gas", "options": { "dripline_endpoint": "mbar_CC10_Inj_Gas" } },
    { "number": 268435458, "name": "A.PS.Diss.Coax", "options": { "dripline_endpoint": "A_PS_Diss_Coax" } },
    { "number": 268435459, "name": "mbar.IG.Vac.AS", "options": { "dripline_endpoint": "mbar_IG_Vac_AS" } },
    { "number": 268435460, "name": "V.CC10.Inj.Gas", "options": { "dripline_endpoint": "V_CC10_Inj_Gas" } },
    { "number": 268435461, "name": "A.PS.Diss.AS", "options": { "dripline_endpoint": "A_PS_Diss_AS" } },
    { "number": 268435462, "name": "mbar.IG.Vac.MS", "options": { "dripline_endpoint": "mbar_IG_Vac_MS" } },
    { "number": 268435463, "name": "degC.RTD5.Acc.AS", "options": { "dripline_endpoint": "degC_RTD5_Acc_AS" } },
    { "number": 268435464, "name": "degC.RTD1.Acc.AS", "options": { "dripline_endpoint": "degC_RTD1_Acc_AS" } },
..... (continues)
]

The location of the configuration file can be specified with an environmental variable, instead of using the program option:

$ export HONEYBEE_CONFIG_PATH=/PATH/TO/YOUR/DIR/SensorTable

With this setting, all the files with the .ktf extension at the indicated directory will be parsed. Hereafter in this documentation, this setting is assumed.

Majority of channels have an automatically-inferred binding to a Dripline end-point:

$ ./install/bin/hb-list-sensors  mbar.IG
[
    { "number": 268435491, "name": "mbar.IG.Vac.AS.ATDS", "options": { "dripline_endpoint": "mbar_IG_Vac_AS" } },
    { "number": 268435503, "name": "mbar.IG.Vac.VSS.ATDS", "options": { "dripline_endpoint": "mbar_IG_Vac_VSS" } },
    { "number": 268435606, "name": "mbar.IG.Vac.MS.ATDS", "options": { "dripline_endpoint": "mbar_IG_Vac_MS" } }
]

Some channels have an explicit binding described in the config file:

$ ./install/bin/hb-list-sensors  V.ThrmCpl.Diss.AS
[
    { "number": 268435464, "name": "V.ThrmCpl.Diss.AS.ATDS", "options": { "dripline_endpoint": "V_ThermoCo_Diss_AS" } }
]

(note that namings are not consistent here: ThrmCpl vs ThermoCo; the config file was used to absorb the error.)

Instead of binding to a Dripline endpoint, some channels have a calibration associated to another input channel:

$ ./install/bin/hb-list-sensors  ThrmCpl.Diss.AS
[
    { "number": 268435464, "name": "V.ThrmCpl.Diss.AS.ATDS", "options": { "dripline_endpoint": "V_ThermoCo_Diss_AS" } },
    { "number": 268435465, "name": "degC.ThrmCpl.Diss.AS.ATDS", "default_calibration": "V:5.1865e-01+V*(-7.0934e+04+V*(-2.4686e+06+V*(-1.3643e+08+V*(-3.3825e+09+V*(-3.5836e+10)))))" },
    { "number": 268435466, "name": "K.ThrmCpl.Diss.AS.ATDS", "default_calibration": "degC:degC+273.15" }
]

Multiple calibrations can be chained (as in this example, V -> degC -> K).

These bindings and calibrations can be displayed with the --verbose option:

$ ./install/bin/hb-list-sensors  --verbose
##INFO: honeybee.cc:98: Dripline Datasource: p8_db_user:****@localhost:5432/p8_sc_db
##INFO: pgsql.cc:36: connecting to DB (postgresql://p8_db_user:****@localhost:5432/p8_sc_db)...
##INFO: pgsql.cc:42:     DB connected.
##INFO: data_source.cc:126: Found Dripline ID-Map
##INFO: data_source.cc:145: Dripline Sensor-Name Column: endpoint_name
##INFO: data_source.cc:41: Calibration Chain:
##INFO: data_source.cc:52:     degC.ThrmCpl.Diss.AS.ATDS <= V.ThrmCpl.Diss.AS.ATDS : V:5.1865e-01+V*(-7.0934e+04+V*(-2.4686e+06+V*(-1.3643e+08+V*(-3.3825e+09+V*(-3.5836e+10)))))
##INFO: data_source.cc:52:     K.ThrmCpl.Diss.AS.ATDS <= degC.ThrmCpl.Diss.AS.ATDS : degC:degC+273.15
##INFO: data_source.cc:52:     K.RTD0.Acc.AS.ATDS <= degC.RTD0.Acc.AS.ATDS : degC:degC+273.15
##INFO: data_source.cc:52:     K.RTD1.Acc.AS.ATDS <= degC.RTD1.Acc.AS.ATDS : degC:degC+273.15
(... lines skipped)
##INFO: data_source.cc:152: getting Dripline end-point names...
##INFO: data_source.cc:159:     20 end-points found.
##INFO: data_source.cc:168: Dripline Endpoints: 
##INFO: data_source.cc:170:     degC_RTD2_Acc_AS
##INFO: data_source.cc:170:     mbar_CC10_Inj_Gas
##INFO: data_source.cc:170:     A_PS_Diss_Coax
(... lines skipped)
##INFO: sensor_table.cc:224: Sensor ID matching or creation
##INFO: sensor_table.cc:226:     Namespace: dripline_endpoint
##INFO: sensor_table.cc:227:     Basename: ATDS
##INFO: sensor_table.cc:257:     Inferred: degC_RTD2_Acc_AS => degC.RTD2.Acc.AS.ATDS
##INFO: sensor_table.cc:257:     Inferred: mbar_CC10_Inj_Gas => mbar.CC10.Inj.Gas.ATDS
##INFO: sensor_table.cc:274:     Created: A_PS_Diss_Coax => A.PS.Diss.Coax.ATDS
##INFO: sensor_table.cc:257:     Inferred: mbar_IG_Vac_AS => mbar.IG.Vac.AS.ATDS
##INFO: sensor_table.cc:245:     Explicit: V_ThermoCo_Diss_AS => V.ThrmCpl.Diss.AS.ATDS
(... lines skipped)
##INFO: data_source.cc:178: Dripline Endpoint Binding: 
##INFO: data_source.cc:185:     sccm_Alicat_Inj_Gas => sccm.Alicat.Inj.Gas.ATDS
##INFO: data_source.cc:185:     degC_Alicat_Inj_Gas => degC.Alicat.Inj.Gas.ATDS
##INFO: data_source.cc:185:     psia_Alicat_Inj_Gas => psia.Alicat.Inj.Gas.ATDS
##INFO: data_source.cc:185:     V_CC10_Inj_Gas => V.CC10.Inj.Gas.ATDS
##INFO: data_source.cc:185:     mbar_CC10_Inj_Gas => mbar.CC10.Inj.Gas.ATDS
(... lines skipped)

Note:

• Calibrations are applied at run-time, enabling retrospective updates.
• Identity calibration can be used for channel mapping.
• Calibration can be also used for decoding (unpacking of packed bits etc).

All the entries in the config file can be placed under a conditional block (valid_if), enabling time-dependent calibration and mapping.

#         module:
#           id: { name: ThrmCpl, label: Thermocouple }
#           channel:
#             valid_if: date < 20220201
#             id: { name: degC, label: Temperature in Celsius }
#             default_calibration: V:5.1865e-01-7.0934e+04*V + 23.0
#           channel:
#             valid_if: date >= 20220201
#             id: { name: degC, label: Temperature in Celsius }
#             default_calibration: V:5.1865e-01-7.0934e+04*V

This particular example assumes the thermo-couple cold junction compensation was added on 1 Feb 2022.

Theoretically, for more complicated cases, the sensor table contents can be overwritten at run time based on external data, something like below stored in a SQL DB or CSV file:

Sensor,ValidityStart,ValidityEnd,Calibration
degC.ThrmCpl.Diss,2021-01-01T00:00:00,9999-01-01T00:00:00,V:0.519*V+28.0
degC.ThrmCpl.Diss,2022-02-01T08:00:00,9999-01-01T00:00:00,V:0.519*V

Data Access

[As of Apr 20 2022, the UW ATD setup has been down since Mar 4. Only CC10.Inj.Gas and ThrmCpl.Diss produce varying values for this period.]

Using the sensor names, data can be obtained with the install/bin/hb-get-data command:

$ ./install/bin/hb-get-data  --from=2022-03-04T22:00:00  --length=60   sccm.Inj  K.ThrmCpl  mbar.IG.MS
DateTime,TimeStamp,sccm.Inj,K.ThrmCpl,mbar.IG.MS
2022-03-04T22:00:05,1646431205,4.999,502.444,6e-09
2022-03-04T22:00:15,1646431215,5,512.539,6e-09
2022-03-04T22:00:25,1646431225,5.001,521.774,6e-09
2022-03-04T22:00:35,1646431235,4.998,530.772,6e-09
2022-03-04T22:00:45,1646431245,5.002,539.792,6e-09
2022-03-04T22:00:55,1646431255,4.999,548.503,6e-09

If time range is not specified with --from and/or --length, the last 1 minute data will be shown by default. (The default length is 1 minute, and the default from is length seconds ago. Also --to can be used instead of --from or --length.)

--summary option calculates digested values:

$ ./install/bin/hb-get-data   sccm.Inj  K.ThrmCpl  --summary=n,mean,std
{
    "sccm.Inj": { "n": 6, "mean": 4.99983, "std": 0.00147196 },
    "K.ThrmCpl": { "n": 6, "mean": 525.971, "std": 17.1657 },
    "mbar.IG.MS": { "n": 6, "mean": 6e-09, "std": 0 }
}

Each sensor is read out at its own timing, therefore data points are not (necessarily) aligned. In order to display the data in the table format (CSV), resampling is internally applied. Parameters to the resampler can be specified with the --resample=[INTERVAL[,METHOD]] option:

$ ./install/bin/hb-get-data  --from=2022-03-04T22:00:00  --length=60  --resample=20,mean   sccm.Inj  K.ThrmCpl  mbar.IG.MS
DateTime,TimeStamp,sccm.Inj,K.ThrmCpl,mbar.IG.MS
2022-03-04T22:00:10,1646431210,4.9995,507.491,6e-09
2022-03-04T22:00:30,1646431230,4.9995,526.273,6e-09
2022-03-04T22:00:50,1646431250,5.0005,544.147,6e-09

Both the resampler parameters are optional. If the interval parameter is not specified (or zero is given), the time buckets are determined automatically based on the majority of the input data intervals. The default reduction method is middle, which takes one data point closest to the center of each time bucket. By taking one data point (at most) from each time bucket, the fluctuations in the data is preserved. If this is not necessary, mean would be a better reduction method.

If resampling is not necessary, each time-series data can be displayed individually with the --series option:

$ ./install/bin/hb-get-data  --from=2022-03-04T22:00:00  --length=120   --series   sccm.Inj  K.ThrmCpl  mbar.IG.MS
{
    "sccm.Inj": {
      "start": 1646431200, "length": 120,
      "t": [1.3,11.3,21.3,31.3,41.3,51.3,61.3,71.3,81.3,91.3,101.3,111.3],
      "x": [4.999,5,5.001,4.998,5.002,4.999,5.003,4.997,5.001,5.001,4.999,5]
    },
    "K.ThrmCpl": {
      "start": 1646431200, "length": 120,
      "t": [1.3,11.3,21.3,31.3,41.3,51.3,61.3,71.3,81.3,91.3,101.3,111.3],
      "x": [502.444,512.539,521.774,530.772,539.792,548.503,557.22,565.721,573.955,582.233,590.24,598.056]
    },
    "mbar.IG.MS": {
      "start": 1646431200, "length": 120,
      "t": [1.3,11.3,21.3,31.3,41.3,51.3,61.3,71.3,81.3,91.3,101.3,111.3],
      "x": [6e-09,6e-09,6e-09,6e-09,6e-09,6e-09,6e-09,6e-09,6e-09,6e-09,6e-09,6e-09]
    }
}

C++ API

Example Program

This example can be found in install/Examples/Honeybee/demo-honeybee.cxx.

// demo-honeybee.cxx //

#include <string>
#include <vector>
#include <iostream>
#include "honeybee/honeybee.hh"

namespace hb = honeybee;

int main(int argc, char** argv)
{
    std::vector<std::string> t_sensors = { "sccm.Alicat.Inj", "K.ThrmCpl.Diss", "mbar.IG.MS" };
    hb::datetime t_from("2022-01-26T08:00:00"), t_to("2022-01-26T08:10:00");

    hb::honeybee_app t_honeybee;
    //t_honeybee.add_dripline_db("p8_db_user:****@localhost:5432/p8_sc_db");
    
    auto t_series_bundle = t_honeybee.read(t_sensors, t_from, t_to);

    
    //// Raw Data, element access by index ////
    std::cout << "### Raw Data ####" << std::endl;
    for (const auto& t_name: t_series_bundle.keys()) {
        auto& t_series = t_series_bundle[t_name];
        const std::vector<double>& t = t_series.t();
        const std::vector<double>& x = t_series.x();
        std::cout << t_name << ": ";
        for (unsigned k = 0; k < t_series.size(); k++) {
            std::cout << "(" << t[k] << "," << x[k] << "),";
        }
        std::cout << std::endl;
    }

    //// Reduction / Summarizing ////
    std::cout << "### Reduced to N, Mean and Std ####" << std::endl;
    for (const auto& t_item: t_series_bundle.items()) { // item: pair of name and series
        std::cout << t_item.first << ": ";
        std::cout << t_item.second.reduce(hb::reduce_to_count) << ", ";
        std::cout << t_item.second.reduce(hb::reduce_to_mean) << ", ";
        std::cout << t_item.second.reduce(hb::reduce_to_std) << std::endl;
    }

    //// Resampling (down-sampling with a reducer and up-sampling with a filler) ////
    hb::resampler t_resampler(hb::group_by_time(60), hb::reduce_to_mean, hb::fillna_with_prev);
    std::cout << "### Resampled ####" << std::endl;
    for (const auto& t_series: t_series_bundle) {
        hb::series t_series_resampled = t_series.apply(t_resampler);
        std::cout << t_series_resampled.to_json() << std::endl;
    }
    
    //// Data Frame ////
    std::cout << "### Data Frame ####" << std::endl;
    hb::data_frame t_data_frame(t_series_bundle, t_resampler);
    for (auto row: t_data_frame.rows()) {
        std::cout << long(row.t()) << "   ";
        for (auto col: row) {
            std::cout << col << "  ";
        }
        std::cout << std::endl;
    }

    return 0;
}

The CMaleLists.txt file in the example directory searches for all the files with the .cxx extension.

$ cd install/Examples/Honeybee
$ cmake .
$ make

Before running, make sure that the ssh-tunneling to Dripline DB has been established.

$ ./demo-honeybee
### Raw Data ####
sccm.Alicat.Inj: (1643184001,0.002),(1643184011,0.002),(1643184021,0.002), (...line trimmed)
K.ThrmCpl.Diss: (1643184001,265.949),(1643184011,265.982),(1643184021,265.917), (...line trimmed)
mbar.IG.MS: (1643184009,8.8e-08),(1643184019,8.8e-08),(1643184029,8.8e-08), (...line trimmed)
### Reduced to N, Mean and Std ####
sccm.Alicat.Inj: 60, 0.002, 1.31202e-18
K.ThrmCpl.Diss: 60, 265.881, 0.0570167
mbar.IG.MS: 49, 8.75102e-08, 5.05076e-10
### Resampled ####
{
  "start": 1643184000, "length": 600,
  "t": [30,90,150,210,270,330,390,450,510,570],
  "x": [0.002,0.002,0.002,0.002,0.002,0.002,0.002,0.002,0.002,0.002]
}
{
  "start": 1643184000, "length": 600,
  "t": [30,90,150,210,270,330,390,450,510,570],
  "x": [265.926,265.886,265.859,265.898,265.918,265.909,265.849,265.849,265.878,265.842]
}
{
  "start": 1643184000, "length": 600,
  "t": [30,90,150,210,270,330,390,450,510,570],
  "x": [8.8e-08,8.8e-08,8.8e-08,8.78333e-08,8.76667e-08,8.71667e-08,8.7e-08,8.7e-08,8.7e-08,8.7e-08]
}
### Data Frame ####
1643184030   0.002  265.926  8.8e-08  
1643184090   0.002  265.886  8.8e-08  
1643184150   0.002  265.859  8.8e-08  
1643184210   0.002  265.898  8.78333e-08  
1643184270   0.002  265.918  8.76667e-08  
1643184330   0.002  265.909  8.71667e-08  
1643184390   0.002  265.849  8.7e-08  
1643184450   0.002  265.849  8.7e-08  
1643184510   0.002  265.878  8.7e-08  
1643184570   0.002  265.842  8.7e-08  

Data Objects

Example here can be found in install/bin/Examples/Honeybee/demo-series.cxx.

Series

The series class represents one chain of time-series data.

    class series {
        double f_start, f_stop;
        std::vector<double> f_t, f_x;
      public:
        std::vector<double>& t();
        std::vector<double>& x();
        double get_start() const;
        double get_stop() const;

Although the implementation is a struct of arrays, {t[],x[]}, the class provides interface for an array of structs, {t,x}[]:

        // as {t[],x[]}
        for (unsigned k = 0; k < t_series.size(); k++) {
            cout << long(t_series.t()[k]) << "," << t_series.x()[k] << endl;
        }

        // as {t,x}[]
        for (unsigned k = 0; k < t_series.size(); k++) {
            cout << long(t_series[k].t()) << "," << t_series[k].x() << endl;
        }

        // as {t,x}[], range-based
        for (auto t_tx: t_series) {
            cout << long(t_tx.t()) << "," << t_tx.x() << endl;
        }

Algorithms for series are generally implemented as a functor. For example,

    t_series.apply_inplace(fillna_with(0));
    double mean = t_series.reduce(reduce_to_mean);

Here are the methods to apply a functor:

   public:
      series apply(function<series(const series&)> a_transformer) const;
      series apply(function<double(double)> a_mapper) const;
      series& apply_inplace(function<series&(series&)> a_transformer);
      series& apply_inplace(function<double(double)> a_mapper);
      double reduce(function<double(const series&)> a_reducer) const:
      series filter(function<bool(double)> a_filter) const;

Currently the following functors are available:

• to apply: dropna, resample(...)
• to apply_inplace: fillna_with(val), fillna_with_prev, fillna_with_next, fillna_with_closest, fillna_by_line, keepna
• to reduce: reduce_to_XXX where XXX is mean, median, min, max, count, sum, std, var, first, last, middle

To apply an mutating functor to a const object, use clone():

    series t_series_2 = t_series_1.clone().apply_inplace(fillna_by_line);

For the other way, not crating an additional variable even for non-mutating functors,

    (t_series = t_series.apply(dropna)).apply_inplace(...

Resampling

Resampler is implemented as a functor to series. It performs:

1. grouping: break time-series into time buckets
2. reducing: for each bucket, reduce data points to a scalar value (or NaN if no data point exists)
3. filling: for each bucket, replace NaN (called na following Pandas) with a value

If a bucket contains multiple data points, the step 2 performs down sampling. If data points are sparse compared to the buckets, the step 3 performs up sampling.

Algorithms for grouping, reducing and filling are provided to the resampler as functors. If smaller fluctuations by averaging is preferable or acceptable, it should typically look like:

    resampler t_resampler(group_by_time(10), reduce_to_mean, fillna_by_line);
    series t_resampled_series = t_series.apply(t_resampler);

where linear interpolation is used by fillna_by_line. If it is only for down sampling with keeping the fluctuations (i.e., to emulate sampling at a lower rate),

    resampler t_resampler(group_by_time(10), reduce_to_middle, keepna);
    series t_resampled_series = t_series.apply(t_resampler);

where reduce_to_middle, as well as reduce_to_first and reduce_to_last, takes one sample per bucket, and keepna does not perform any kind of interpolation; for data from sparse or lazy recording, fillna_with_closest or fillna_with_prev might be used instead.

Series Bundle

The honeybee::zip(key_vector, value_vector) combines two input vectors and makes an ordered map of key-value, something similar to Python's OrderedDict. It is often convenient to zip a set of series data with their names:

    vector<string> t_name_list{ "sccm.Alicat", "K.ThrmCpl.Diss", "mbar.IG.AS" };
    vector<hb::series> t_series_list = read data...;
    auto t_series_bundle = hb::zip(t_name_list, t_series_list);

    for (const string& a_name: t_series_bundle.keys()) {
        cout << a_name << ": " << t_series_bundle[a_name].to_json() << endl;
    }

In addition to the key-based access, index-based access is still available, just like vector<series>:

        for (hb::series& t_series: t_series_bundle) {
            cout << t_series.to_json() << endl;
        }

It also can be iterated over the (key, series) pairs:

        for (auto t_item: t_series_bundle.items()) {
            cout << t_item.first << ": " << t_item.second.to_json() << endl;
        }

The zip of vector<string> and vector<series> is typedef-ed as series_bundle.

Data Frame

Data Frame is a bundle of aligned (resampled) series.

    hb::data_frame t_data_frame(t_series_bundle, hb:resampler(hb:group_by_time(10), hb::reduce_to_mean, hb::fillna_with_last);
    cout << t_data_frame.to_csv();

Data Frame provides three shapes to access data: 1) 2-dim matrix, 2) row-oriented tables, and 3) column-oriented bundle of series.

   // matrix of doubles
   for (unsigned i = 0; i < t_data_frame.number_of_rows(); i++) {
      cout << long(t_data_frame.t()[i]) << "    ";
      for (unsigned j = 0; j < t_data_frame.number_of_columns(); j++) {
         cout << t_data_frame[i][j] << "  ";
      }
      cout << endl;
   }

   // row-oriented (array of records)
   for (auto t_record: t_data_frame.rows()) {
      cout << long(t_record.t()) << "   ";
      for (double xk: t_record) {
         cout << xk << "  ";
      }
      // xk can also be accessed like t_record[t_column_index]
      // xk can also be accessed like t_record[t_column_name]
      cout << endl;
   }

   // column-oriented (bundle of series)
   for (series& t_col: t_data_frame.columns()) {  // t_col is just a series
       for (double xk: t_col.x()) {
           cout << xk << "  ";
       }
       cout << std::endl;
   }

   // column-oriented, by names (bundle of series)
   for (string t_col_name: t_data_frame.column_names()) {
      cout << t_col_name << ": ";
      for (auto pk: t_data_frame[t_col_name]) {  // t_data_frame[t_col_name] is just a series
         cout << pk.x() << "  ";
      }
      cout << endl;
   }

Sensors and Sensor Table

Sensor Name

Sensors are organized in a tree structure. Sensor names are a chain of mnemonic, such as sccm.Alicat.Inj.Gas.AS.ATDS and K.ThrmCpl.Diss.AS.ATDS, where each mnemonic corresponds to a node in the sensor tree, and the separator (. here) is arbitrary. The corresponding class is:

    class name_chain {
        vector<string> f_chain;
      public:
        name_chain(const vector<string>& a_chain);
        name_chain(string a_joined, string a_sep);
        string& operator[](int index);
        string join(const string& a_sep=".") const;
    };

For performance reasons, sensors are internally handled with an integer sensor_number. Also each sensor name node has a descriptive label. The sensor class is composed of these:

    class sensor {
        int f_number;
        name_chain f_name;
        name_chain f_label;
        string f_calibration;
      public:
        int get_number() const;
        const name_chain& get_name() const;
        const name_chain& get_label() const;
        const string& get_calibration() const;
        operator int() const { return f_number; }
      };

The type-cast operator to int enables us to handle a sensor object as an integer value.

While majority of sensors are bound to entries in data sources (such as Dripline SQL DB), some sensor values are derived from values of other sensors. The optional calibration field describes this.

Sensor Table

Sensor table organizes all the sensors in the system.

    class sensor_table {
      public:
        const sensor& operator[](int a_number) const;
        const sensor& operator[](const name_chain& a_name) const;
        vector<int> find_like(const name_chain& a_chain) const;

The array operator [] converts a sensor number or name to a corresponding sensor object, and find_like method searches for sensors that have a (partly) matching name.

The sensor table can be configured by multiple ways. For the simplest system, it can be configured based on entries in a data source such as the Dripline SQL DB:

    hb::sensor_table t_table;
    
    hb::sensor_config_by_names t_config;
    hb::dripline_pgsql t_dripline_db("p8_db_user:****@localhost:5432/p8_sc_db");
    t_config.load(t_table, t_dripline_db.get_data_names(), {{"ATDS"}});

For a managed system, sensor entries are typically described in a config file:

    hb::sensor_table t_table;
    
    hb::sensor_config_by_file t_config;
    t_config.set_variables({{"version", 3}, {"date", 20201010}});
    t_config.load(t_table, "PATH/TO/CONF/SensorTable_ATDS.ktf");

Here the configuration file does not have to list all the sensors. If entries constructed from a data source is sufficient, they can be used in that way.

Sensor configuration file can have variables (version and date in this example) for conditional contents.

Example

Example here can be found in install/bin/Examples/Honeybee/demo-sensor-table.cxx.

// demo-sensor-table.cxx //

#include <iostream>
#include <honeybee/honeybee.hh>
namespace hb = honeybee;

int main(int argc, char** argv)
{
    hb::sensor_table t_table;
    
    hb::sensor_config_by_file t_config;
    t_config.set_variables({{"version", 3}, {"date", 20201010}});
    t_config.load(t_table, "../../../SensorTable/SensorTable_ATDS.ktf");
    
    hb::sensor t_sensor = t_table[{{"mbar","IG","Vac","MS","ATDS"}}];
    std::cout << "number: " << t_sensor.get_number() << std::endl;
    std::cout << "name: " << t_sensor.get_name().join(".") << std::endl;
    std::cout << "label: " << t_sensor.get_label().join(", ") << std::endl << std::endl;
    
    for (auto& t_number: t_table.find_like({{"mbar","IG"}})) {
        std::cout << t_table[t_number].get_name().join(".") << std::endl;
    }

    return 0;
}

$ ./demo-sensor-table 
number: 268435606
name: mbar.IG.Vac.MS.ATDS
label: Pressure, Ion Gauge, Vacuum, Mass Spectrometer, Atomic Tritium Demonstrator in Seattle

mbar.IG.Vac.AS.ATDS
mbar.IG.Vac.VSS.ATDS
mbar.IG.Vac.MS.ATDS

To loop over all the defined channels, use find_like() with an empty match pattern:

    // this will display all the channels
    for (auto& t_number: t_table.find_like({{}})) {
        std::cout << t_table[t_number].get_name().join(".") << std::endl;
    }

Data Source

The data_source class is an abstraction to various types of data source implementations, such as Dripline DB, other time-series DB, and CSV files. It defines interfaces 1) to query sensor names defined in the data source, and 2) to fetch data from the data source.

    class data_source {
      public:
        data_source() {}
        virtual ~data_source() {}
        virtual vector<string> get_data_names() = 0;
        virtual void bind(sensor_table& a_sensor_table);
        virtual vector<series> read(const vector<int>& a_sensor_list, double a_from, double a_to);

The bind() method constructs bindings between sensor entries defined in the sensor table and entries in the data source.

Currently only Dripline PostgreSQL data source is implemented:

    class dripline_pgsql: public data_source {
      public:
        dripline_pgsql(string a_uri, name_chain a_basename=name_chain());

where a_basename is used to define a namespace for the DB entries (such as ATDS for the DB system for the UW Atomic Tritium test-stand).

Combined with the sensor table construction based on DB contents, a minimal system to fetch data is something like this: (available in install/Examples/Honeybee/demo-data-source.cxx)

// demo-data-source.cxx //

#include <iostream>
#include <honeybee/honeybee.hh>
namespace hb = honeybee;

int main(int argc, char** argv)
{
    // define data source //
    hb::dripline_pgsql t_data_source("p8_db_user:****@localhost:5432/p8_sc_db");
   
    // construct Sensor Table //
    hb::sensor_table t_sensor_table;
    hb::sensor_config_by_names t_config;
    t_config.load(t_sensor_table, t_data_source.get_data_names());

    // bind sensor entries to DB contents //
    t_data_source.bind(t_sensor_table);
    
    // fetch //
    std::vector<int> t_sensors = t_sensor_table.find_like({{"Alicat"}});
    hb::datetime t_from("2022-01-26T08:00:00"), t_to("2022-01-26T08:01:00");
    std::vector<hb::series> t_series_list = t_data_source.read(t_sensors, t_from, t_to);

    // print //
    for (unsigned i: hb::arange(t_sensors)) {
        std::cout << t_sensor_table[t_sensors[i]].get_name().join(".") << ": ";
        std::cout << t_series_list[i].to_json() << std::endl;
    }
    
    return 0;
}

$ ./demo-data-source 
sccm.Alicat.Inj.Gas: {
  "start": 1643184000, "length": 60,
  "t": [1.3,11.3,21.3,31.3,41.3,51.3],
  "x": [0.002,0.002,0.002,0.002,0.002,0.002]
}
psia.Alicat.Inj.Gas: {
  "start": 1643184000, "length": 60,
  "t": [1.2,11.2,21.2,31.2,41.2,51.2],
  "x": [7.3,7.4,7.3,7.3,7.2,7.3]
}
degC.Alicat.Inj.Gas: {
  "start": 1643184000, "length": 60,
  "t": [1.3,11.3,21.3,31.3,41.3,51.3],
  "x": [30.85,30.85,30.85,30.85,30.85,30.84]
}

Wrapping Up

The honeybee_app class wraps up the data access part for convenience:

    class honeybee_app {
      public:
        void add_config_file(const std::string& filepath);
        void add_dripline_db(const std::string& db_uri);
        void add_variable(const std::string& key, const KVariant& value);
        void set_delimiter(const std::string& delimiters);
        std::shared_ptr<sensor_table> get_sensor_table();
        std::shared_ptr<data_source> get_data_source();
        std::vector<std::string> find_like(const std::string a_name);
        series_bundle read(const vector<std::string>& a_sensor_list, double a_start, double a_stop);

If no sensor configuration is given by calling add_config_file() or add_dripline_db(), it will search for (a) configuration file(s) in the directory indicated by the HONEYBEE_CONFIG_PATH environmental variable.

The configuration file can contain, in addition to the sensor table configuration, the data source information.

# data_source:
#  dripline_psql:
#    uri: p8_db_user:****@localhost:5432/p8_sc_db
#    basename: ATDS

# sensor_table:
#   setup:
#     id: { name: ATDS, label: Atomic Tritium Demonstrator in Seattle }
#     valid_if: date > 20201001

#     section:
#       id: { name: Gas, label: Gas Handling }
#       subsection:
#         id: { name: Inj, label: Injection }
(... more lines)

With the environmental variable defined, and the Dripline DB URL is described in a configuration file (even without the sensor table part), the user C++ code becomes very simple.

To look up sensors:

#include "honeybee/honeybee.hh"
namespace hb = honeybee;

int main(int argc, char** argv)
{
    hb::honeybee_app t_honeybee;
    for (std::string& t_name: t_honeybee.find_like("mbar.Vac")) {
        std::cout << t_name << std::endl;
    }
...

To get data:

#include "honeybee/honeybee.hh"
namespace hb = honeybee;

int main(int argc, char** argv)
{
    std::vector<std::string> t_sensors = { "sccm.Alicat.Inj", "K.ThrmCpl.Diss", "mbar.IG.MS" };
    hb::datetime t_from("2022-01-26T08:00:00"), t_to("2022-01-26T08:10:00");

    hb::honeybee_app t_honeybee;
    auto t_series_bundle = t_honeybee.read(t_sensors, t_from, t_to);
...

Design and Implementation

Sensor Configuration

Sensors are organized in a tree structure. Sensor table can be described in (a) YAML-like configuration file (s).

# sensor_table:
#   setup:
#     id: { name: ATDS, label: Atomic Tritium Demonstrator in Seattle }
#     valid_if: date > 20201001

#     section:
#       id: { name: Gas, label: Gas Handling }
#       subsection:
#         id: { name: Inj, label: Injection }
#         module:
#           id: { name: Alicat, label: Alicat Flowmeter }
#           channel:
#             id: { name: sccm, label: Flow }
#           channel:
#             id: { name: degC, label: Temperature }
#           channel:
#             id: { name: psia, label: Pressure }
#         module:
#           id: { name: CC10, label: CC10 Pressure Gauge }
#           channel:
#             id: { name: V, label: LabJunk Voltage }
#           channel:
#             id: { name: mbar, label: Pressure }
(... more lines)

(This format will be / cab be replaced with YAML. A major difference from YAML is that multiple child nodes with the same tag name create an array, which is actually convenient and improves readability and writablity...)

Layers are defined in this example like setup → section → module → channel, but the layers can be of any depth with any of the following layer tags:

• experiment, setup, teststand, system
• section, subsection, division, segment, crate
• module, device, card, board (unit is NOT included on purpose)
• channel, endpoint, metric

Currently Honeybee does not care which layer has which tag, but this might be changed in the future. A good practice will be to use one in the first set for the top-level, and one in the bottom set for data-producing nodes (i.e., leaves of the tree).

Each layer must have an id, with at least a name and optionally with a label. A full sensor name will be a concatenation of the layer names, with an arbitrary separator (typically one of ., _, -, /, :, ;), in the reversed order (leaf to root).

An integer sensor number will be assigned for each leaf node by the system at run-time. This assignment of the numbers is not fixed and cannot be used for persistent purposes.

Each layer can have a valid_if tag, with a value of the tag being a conditional expression with variables. The variables can be provided by users at run-time.

Optional key-value pairs can be added, with a key name staring with x-. Explicit binding to a Dripline endpoint, for example, is described with x-dripline_endpoint, where the content is specific to the Dripline data source.

Data Entry Binding, Channel Mapping, and Calibrations

The data_source::bind() method manages bindings between the sensor entries and the DB contents, and/or mappings among sensor table entries (calibrations).

If a sensor table is constructed from DB contents only, the sensor names are basically identical to those defined in the data source, optionally with an appended basename. If the names in the data source contain delimiters, such as _, the names are broken down into a chain, enabling users to use the partial name matching. Moreover, if a configuration file is to be used later, already using a consistent naming structure in the database (i.e., organized in a tree, separated by a delimiter) makes the future configuration simpler; here "convention over configuration" (CoC) takes place. For example, Honeybee can automatically infer the binding between a sensor name of sccm.Alicat.Inj.Gas.AS.ATDS and a dripline endpoint of sccm_Alicat_Gas in namespace ATDS.

Beyond simple data access using names in data source, configuration by file or database becomes necessary. The configuration can contain:

• explicit binding between sensor names and data store entries
• derived sensor entries, whose values are calculated from other sensor values (calibrations)
• conditional block depending on external parameters such as date

Note that the calibrations can be used for:

• calibrating the device
• converting units
• mapping between channels (physics quantity to sensor, sensor to digitizer, digitizer to end-point, etc)
• decoding packed bits

See the Quick Tour section for examples.

Calibration implementation

Calibration is a text property of a sensor, stored in std::string f_calibration of the sensor class. The text is a lambda expression with a input from another sensor, or inputs from other sensors, in a form of:

INPUT: f(INPUT)

In a sensor configuration file, this is described as the default_calibration property of a channel:

#         module:
#           id: { name: ThrmCpl, label: Thermocouple }
#           channel:
#             id: { name: V, label: Voltage }
#             x-dripline_endpoint: V_ThermoCo_Diss_AS
#           channel:
#             id: { name: degC, label: Temperature in Celsius }
#             default_calibration: V:5.1865e-01+V*(-7.0934e+04+V*(-2.4686e+06+V*(-1.3643e+08+V*(-3.3825e+09+V*(-3.5836e+10)))))
#           channel:
#             id: { name: K, label: Temperature in Kelvin }
#             default_calibration: degC:degC+273.15

Here the K.ThrmCpl has a calibration with an input from degC (of ThrmCpl by default).

data_source::bind() parses the text at run-time (currently using the "Kebap" library) and holds an evaluator object together with a link to input sensor(s).

Python Binding (Plan)

Export only:

• honeybee_app::find_like()
• honeybee_app::read(), returning a list of Panda's Series