Data Loss

Remove rows conditionally if one column does not include a set of required strings within groups defined by another column, in R

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Summary The problem requires removing rows from a data frame if a group, defined by one column, does not contain a set of required strings within another column. This can be achieved using base R or the dplyr/tidyverse package in R. Root Cause The root cause of the problem is the need to filter groups … Read more

BIAS CORRECTION

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Summary The task at hand involves bias correction of precipitation data using quantile mapping to combine gauge station data with CHIRPS (Climate Hazards Group InfraRed Precipitation with Station) data. This is necessary because the gauge stations are sparse, covering a large catchment area of 6000 km², and CHIRPS data can help fill in the gaps. … Read more

Nagios 4 on fresh Mint 22.3

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Summary The issue at hand involves a fresh installation of Linux Mint 22.3 (Cinnamon) where Nagios 4 is installed using the official packages via apt install nagios. However, upon installation, the system fails to reboot properly, often resulting in a bootloop or getting stuck on the kernel/initramfs screen. This article aims to explore the root … Read more

Will the awakened thread be able to read the latest data if write operations are performed on the data without locking before notify_one?

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Summary The question revolves around the behavior of a multithreaded program where a producer thread writes data and then notifies a consumer thread using notify_one without proper locking. The key takeaway is that the behavior of the program is undefined due to the lack of synchronization between the threads. Root Cause The root cause of … Read more

How do I index in R so that my data isn’t deleted when there are no indices?

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Summary This incident centers on an R indexing pattern that unexpectedly empties a vector when the filtering condition matches no elements. The engineer expected the original data to remain intact, but the combination of which() and negative indexing caused the entire vector to be dropped. Root Cause The failure stems from how R interprets negative … Read more

How do you use files with spaces in a (Linux)for?

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Summary This incident stemmed from attempting to rename files containing spaces using a for loop that splits on whitespace. The loop consumed filenames incorrectly, causing mv to receive malformed arguments. The core issue was unsafe shell iteration over filenames. Root Cause Using for i in $(cat file), which forces word splitting and glob expansion. Filenames … Read more

What is the difference between typedef struct {} Node and typedef struct _node{} Node in C?

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Summary In C, the difference between typedef struct {} Node and typedef struct _node{} Node lies in the struct tag and forward declaration. Using a tagged struct (_node) allows for forward referencing, enabling the compiler to recognize the struct before its full definition. This is crucial for self-referential structures like linked lists. Root Cause The … Read more