Many trays

A big greenhouse has twelve trays. One of them is ailing, and by the time you find it, it is gone. The chip should tell you two things: how the greenhouse is doing on average and which tray is the weakest.

Many trays with one name#

If you give all trays the same name, lbns reads them with one instruction:

lbns total TRAY HASH("Beet") 0 Health Sum
lbns num TRAY HASH("Beet") 0 Occupied Sum
lbns minh TRAY HASH("Beet") 0 Health Minimum   # careful: −1

That is fast but has two catches:

1. Empty trays count too. An empty tray returns Health −1. Minimum then reports −1 although all plants are healthy, and Average is pulled down.
2. No name in the result. Minimum tells you the smallest value, but not which tray has it.

Taking empty trays out#

For the average there is a calculation trick. Every empty tray contributes −1 to the sum. If you know the number of trays, you can work it back out:

• planted = sum of Occupied
• empty = trays − planted
• average = (sum of Health + empty) / planted

This works as long as COUNT is right. If you add a tray, you have to adjust the define.

Finding the weakest tray#

To know which tray is weak, each needs its own name: “Beet1” to “Beet4”. You put the hashes of the names into the stack once at start. A loop fetches them with get … db and reads each tray on its own:

poke 0 HASH("Beet1")
poke 1 HASH("Beet2")
start:
yield
move idx 0
loop:
get name db idx
lbns value TRAY name 0 Health Average
bnan value next
bltz value next

The loop skips empty trays (−1) and missing ones (NaN) with bltz and bnan. For the rest it remembers the smallest value and its number.