Known Issues¶

This page contains a list of known issues related to the pipeline that are not currently being worked on. Only issues which cannot be fixed with a new release will be added to this list. Wherever possible, a link to relevent GitHub issues will be provided.

Firefox/geckodriver cannot be found¶

Error message:

RuntimeError: Neither firefox and geckodriver nor a variant of chromium browser and chromedriver are available on system PATH. You can install the former with 'conda install -c conda-forge firefox geckodriver'.

This issue has been submitted by a small number of users. This error is thrown by our plotting library, bokeh, when it can’t automatically find the path to a driver needed to generate plots. The following describes a one-off workaround.

These instructions assume you are using conda to manage your environment.

If you installed the pipeline with pip, uninstall with pip uninstall kcwidrp
Install the pipeline following the Installing for Development instructions on the Installing KCWI_DRP page.
Open KCWI_DRP/kcwidrp/core/kcwi_plotting.py in a text editor
Add the following import at the top of the file:
```
from selenium import webdriver
```
Find your firefox installation by executing which firefox from the command line. Make note of the output. It should look something like /PATH/TO/CONDA/envs/kcwidrp/bin/firefox

Replace the function save_plot with the following:

def save_plot(fig, filename=None):
    if filename is None:
        fnam = os.path.join('plots', 'kcwi_drp_plot.png')
    else:
        fnam = os.path.join('plots', filename)

    options = webdriver.FirefoxOptions()

    options.add_argument("--headless")
    options.add_argument("--hide-scrollbars")
    options.add_argument("--force-device-scale-factor=1")
    options.add_argument("--force-color-profile=srgb")
    driver = webdriver.Firefox(firefox_binary="[YOUR/PATH/HERE]",
                                firefox_options=options)
    export_png(fig, filename=fnam, webdriver=driver)
    driver.close()
    logger.info(">>> Saving to %s" % fnam)

where [YOUR/PATH/HERE] is replaced by the path found in the previous step

Navigate to the KCWI_DRP directory, and run:
```
python setup.py install
```

Massive Slowdown When Calculating Central Dispersion¶

This issue does not throw an error, but can be identified by the logs as it happens. The logs will look something like

2021-06-08 18:49:51:KCWI:INFO: Using TAPERFRAC = 0.200
Bar#:   4, Cdisp: 0.2392
Bar#:   0, Cdisp: 0.2391
Bar#:   8, Cdisp: 0.2393
Bar#:  12, Cdisp: 0.2393
...
Bar#: 119, Cdisp: 0.2397

This step typically takes anywhere from 30 seconds to several minutes, depending on the resources availible to your computer. However, sometimes this step takes upwards of 20 minutes, even on a powerful machine. This appears to be caused by a conflict in thread allocation between various packages used by the pipeline, although the specifics remain unknown.

To fix the issue, you need to specify how threads are allocated directly. This can be done directly from the command line by typing the following lines into your terminal:

export MKL_NUM_THREADS=16
export NUMEXPR_NUM_THREADS=1
export OMP_NUM_THREADS=1

This will not persist between terminal sessions, so you should add it to your .bashrc file.