Installing Cvxopt, NumPy, and SciPy on Travis CI (Translation post)

Preface: I want to get back into the habit of writing blog posts, but I haven’t had much time lately to plan content.  I feel like just getting your fingers typing  is half the battle when it comes to writing, so this time I’ve written the English version of a post my husband just made on Qiita.

While my own strengths tend more towards algorithm development and ‘the mathy bits’, my husband is a cloud computing wizard and is thankfully willing to spend his free time helping me set up things like Travis CI.  Travis CI is a tool I’ve been coveting for a long time.  What it does is spin up a virtual machine and run all your unit tests each time a pull request is created or updated.  You can tell at a glance whether the unit tests are passing or failing, which takes a lot of the work out of pull request evaluation.

Who is this guide for?

People who want to use Travis CI to test programs which require the Cvxopt, NumPy, and SciPy packages.

Continue reading Installing Cvxopt, NumPy, and SciPy on Travis CI (Translation post)

Hydroponics workshop: Starting the Kratky system


Things in the kit:

  • An 11L storage tote container with holes cut for net cups.  We didn’t talk about this specifically during the workshop but if you look at the bottom of the container you’ll see that it’s LDPE, one of the plastic types that is safe for hydroponics in my opinion.
  • 100mL each of Optimum Hydroponix Grow A and Grow B.  It’s not a case of using one for grow and one for bloom, it’s a grow formula that just comes in two parts.  See the article about nutrients if you want to learn about bloom formulas.
  • A liquid-based pH test kit, including testing liquid, vial, and colour chart for reading results.
  • 8 net cups.  This is more than the system holds, but the extras are so you can start germinating new plants as you’re preparing to ‘retire’ some older ones.
  • 8 media cubes (rockwool or Rapid Rooters).  The small rockwool cubes are a good size on their own but Rapid Rooters are a little small.  If using Rapid Rooters, pad their sides with slices cut from an extra cube in order to make a snug fit.  For another media option, you can use larger loose media such as large perlite or coco coir or smaller sized hydroton, or see my post on cloning to see how plastic mesh netting can be used together with smaller grain perlite or coco coir.

Continue reading Hydroponics workshop: Starting the Kratky system

Hydro workshop: NFT case study

The basic idea of the Nutrient Film Technique is that plants sit in net cups suspended a small distance over a thin stream of nutrient solution which is in constant motion.

Generally, a steady stream of water is continually pumped into one end of a channel and a small downward gradient causes the water to flow to the other end thanks to gravity. At the other end of the channel is a connection which allows the water to return to the reservoir, ideally without relying on power so that the water can return to the reservoir in the event of a power outage rather than gathering at one end of the channel.  NFT is best used for shallow rooting plants like lettuce and other greens, herbs, strawberries, etc. Continue reading Hydro workshop: NFT case study