# Recent News

# strace

So, I am not smart, and I have made this mistake enough times that I’m writing it down for both my future self, and also for anyone that encounters the same issue.
I was testing Mesa drivers and ran into the following error:
libGL error: MESA-LOADER: failed to open iris: libLLVM-13.so.1: cannot open shared object file: No such file or directory (search paths /home/jcgregorio/mesa/22.1.3, suffix _dri) libGL error: failed to load driver: iris libGL error: MESA-LOADER: failed to open swrast: libLLVM-13.

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# Wake County Omicron Mortality Rate

I’ve seen many articles on the mortality rate of Covid-19, either nationally or globally, but what I haven’t been able to find is the mortality rate of the Omicron variant for the county I live in, which is a much more relevant piece of information.
Now before we get into what I found, here are some caveats:
I am not a doctor. I am not a virologist. I am not a statistician.

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# 2022

Polarization I pretty much nailed all my predictions for 2021, in particular I wrote about right-wing extremism:
I fully expect Trump, unconstrained by the people that surround him in the White House today, to become even more unhinged and try to inspire even more violent acts of terrorism."
I wrote that two weeks before Jan 6th.
I also wrote about the roots of that violence as a loss of power:

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# Perfetto SPAN_JOIN and LEAD Explained

Perfetto and the SQL processing built into trace_processor are both fantastic, but two of the most important parts of that SQL processing are not well documented, at least for my simple brain.
The first feature is SPAN_JOIN which is described as:
Span join is a custom operator table which computes the intersection of spans of time from two tables or views.
There is a nice diagram showing how the spans are combined:

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# Random Integer Matrices With Inverses That Are Also Integer Matrices

I want to generate a random integer valued \( n \times n \) matrix \( A \) whose inverse is also an integer valued matrix, i.e. how can I generate Unimodular matrices?
The key is starting with an \( n \times n \) identity matrix \( I \), which has a determinant of 1. Then you can apply row operations to \( I \) that keep the determinant 1, i.e. by picking row operations that are expressible as multiplication by a matrix that also has a determinant of 1 with integer components.

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