tl;dr

The discovery of the Fermi Bubbles has led to a lot of interesting speculation about high energy phenomena originating at the center of the Milky Way. The analysis tools applied both in the original discovery and for testing subsequent physical hypotheses leave room for improvement, particularly in terms of moving from qualitative to quantitative assessment of the results. Here we describe one potential approach leveraging Haar wavelets to capture the expected multi-scale nature of structure in all-sky gamma-ray maps, coupled with statistics to quantify the tradeoffs between detection of detail and “false detections” resulting from photon counting noise.

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I recently ran into a requirement where a Google Cloud Function (GCF) seemed a good fit. I wanted to use Clojure for this, at least as a first cut, but the examples I found were centered around ClojureScript/NodeJS, which wound up being a non-starter for various boring reasons. Googling about turned up essentially nothing about how to use JVM Clojure for this purpose. The GCF story for Java is about as easy as it can get, just implement a known interface, uberjar, and deploy with the gcloud tool.

My first attempt in Clojure used gen-class, but deployment resulted in this exception:

"Exception in thread "main" java.lang.ExceptionInInitializerError
	at clojure.lang.Namespace.<init>(Namespace.java:34)
	at clojure.lang.Namespace.findOrCreate(Namespace.java:176)
	at clojure.lang.Var.internPrivate(Var.java:156)
	at ck.proxysql_notifier.<clinit>(Unknown Source)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at com.google.cloud.functions.invoker.NewHttpFunctionExecutor.forClass(NewHttpFunctionExecutor.java:51)
	at com.google.cloud.functions.invoker.runner.Invoker.startServer(Invoker.java:243)
	at com.google.cloud.functions.invoker.runner.Invoker.main(Invoker.java:129)
Caused by: java.io.FileNotFoundException: Could not locate clojure/core__init.class, clojure/core.clj or clojure/core.cljc on classpath.
	at clojure.lang.RT.load(RT.java:462)
	at clojure.lang.RT.load(RT.java:424)
	at clojure.lang.RT.<clinit>(RT.java:338)
	... 11 more" 

Order

In the beginning, there were programs. Programs generally consisted of statements which ran in order. The order was originally an actual physical ordering: instructions on a sequential tape, or a sequence of punch cards. “Order” later became order of lines or “statements” in a text file. Some code may be conditionally executed, and we could jump around with GOTO’s, loops, subroutines, functions, etc. But programs basically consisted of chunks of statements executed in order.