libfec

FastFEC Compatability ​

FastFEC is popular a CLI tool for converting FEC filings to CSV files, created by the Washington Post in 2021. The libfec CLI contains a compatible CLI command to the fastfec CLI, aptly named libfec fastfec.

The libfec fastfec command is meant for users who already use fastfec to try out libfec in their workflows, without completely re-writing their pipelines.

For example, Say we are working with FEC-1781583, Nikki Haley's March 2024 FEC filing. We can download the raw .fec file like so:

bash
curl -o 1781583.fec 'https://docquery.fec.gov/dcdev/posted/1781583.fec'

We can convert that 23MB .fec file into a directory of CSVs with fastfec like so:

bash
$ fastfec 1781583.fec output/
About to parse filing ID 1781583
Trying filename: 1781583.fec
$ tree --du -h output
[ 19M]  output
└── [ 19M]  1781583
    ├── [5.4K]  F3PA.csv
    ├── [ 12M]  SA17A.csv
    ├── [1.3K]  SA17C.csv
    ├── [6.4M]  SA18.csv
    ├── [1.3K]  SA20A.csv
    ├── [177K]  SB23.csv
    ├── [3.2K]  SB28A.csv
    └── [ 132]  header.csv

That creates a new directory output/1781583 with 8 CSVs, containing the itemization data from that filing.

Now with libfec, we can do a similar transformation with the libfec fastfec command:

bash
$ libfec fastfec 1781583.fec output2
$ tree --du -h output2
[ 18M]  output2
└── [ 18M]  1781583
    ├── [5.4K]  F3PA.csv
    ├── [ 12M]  SA17A.csv
    ├── [1.3K]  SA17C.csv
    ├── [6.4M]  SA18.csv
    ├── [1.3K]  SA20A.csv
    ├── [176K]  SB23.csv
    ├── [3.2K]  SB28A.csv
    └── [ 133]  header.csv

Additional libfec fastfec features ​

fastfec requires that the .fec file be pre-downloaded, but libfec fastfec can download FEC filings on the fly:

bash
libfec fastfec FEC-1779004 output2/

This will download FEC-1779004 file and write results to output2/1779004 directly — no curl required!

Benchmarks ​

Benchmarking fastfec is a bit complicated. Using the pre-compiled build from the official fastfec Release seems to show that fastfec is ~11x slower than libfec:

Benchmark 1: ./fastfec -x 1805248.fec
  Time (mean ± σ):      4.754 s ±  0.024 s    [User: 4.686 s, System: 0.034 s]
  Range (min … max):    4.728 s …  4.803 s    10 runs
 
Benchmark 2: libfec fastfec 1805248.fec
  Time (mean ± σ):     411.9 ms ±  10.9 ms    [User: 347.0 ms, System: 52.7 ms]
  Range (min … max):   400.7 ms … 439.2 ms    10 runs
 
Summary
  libfec fastfec 1805248.fec ran
   11.54 ± 0.31 times faster than ./fastfec -x 1805248.fec

But this isn't 100% accurate. I believe the offical builds of fastfec use the debug compilation arguments, and could be faster if compiled with the --release=fast flag.

As an experiment, I built fastfec on my own machine, on top of this PR, which gave faster results:

Benchmark 1: ../../FastFEC/zig-out/bin/fastfec -x 1805248.fec
  Time (mean ± σ):     714.4 ms ±  32.5 ms    [User: 678.2 ms, System: 23.3 ms]
  Range (min … max):   688.7 ms … 800.7 ms    10 runs
 
Benchmark 2: libfec fastfec 1805248.fec
  Time (mean ± σ):     394.4 ms ±   5.0 ms    [User: 339.8 ms, System: 50.1 ms]
  Range (min … max):   389.4 ms … 406.5 ms    10 runs
 
Summary
  libfec fastfec 1805248.fec ran
    1.81 ± 0.09 times faster than ../../FastFEC/zig-out/bin/fastfec -x 1805248.fec

Now this version fastfec is faster than the older version, but libfec is still ~1.8x faster.

So I'd say in general, libfec is faster than fastfec in a head-to-head competition. But they're also very different tools, where libfec can resolve filings for committees and contests, while fastfeec just converts raw .fec files to a single CSV format.