collatz / hailstone numbers on various IA64, ARM64, ASM, C, ObjectiveC, Swift, Java, Python, Rust, Go, CUDA, Metal in GPU single, multi threaded and GPU SIMD environments

[obriensystems]

see work (newer to older)

• current generic repo - https://github.com/ObrienlabsDev/performance
• collatz benchmark IA64 and ARM64 obrienlabs/benchmark#12
• https://github.com/ObrienlabsDev/cuda
• https://github.com/ObrienlabsDev/collatz
• (above extends below)
• https://github.com/obrienlabs/benchmark
• https://github.com/obrienlabs/collatz/blob/master/collatz-nbi/src/main/java/cloud/obrienlabs/collatz/process/ComputeImpl.java
• parallax microcontroller machine language reference
• https://github.com/obrienlabs/electronics/blob/master/propCollatz_13_20120317h.spin#L244

references

• https://www.cs.ucf.edu/~leavens/tech-reports/ISU/TR92-01/TR.pdf
• Eric Roosendaal http://www.ericr.nl/wondrous/pathrecs.html
• Scientific American Jan 1984 - Brian Hayes - https://www.jstor.org/stable/24969271
• Tomás Oliveira e Silva https://sweet.ua.pt/tos/3x_plus_1.html

[obriensystems]

option 3: Java 8 lambda/streams parallelization

see ObrienlabsDev/performance#19

	public void searchCollatzParallel(long oddSearchCurrent, long secondsStart) {
		long batchBits = 5; // adjust this based on the chip architecture 
		long searchBits = 32;
		long batches = 1 << batchBits;
		long threadBits = searchBits - batchBits;
		long threads = 1 << threadBits;
		
		for (long part = 0; part < (batches + 1) ; part++) {	
			// generate a limited collection for the search space - 32 is a good
			System.out.println("Searching: " + searchBits + " space, batch " + part + " of " 
					+ batches + " with " + threadBits +" bits of " + threads + " threads"  );
			
			List<Long> oddNumbers = LongStream
					.range(1L + (part * threads), ((1 + part) * threads) - 1)
					.filter(x -> x % 2 != 0) // TODO: find a way to avoid this filter using range above
					.boxed()
					.collect(Collectors.toList());
			
			List<Long> results = oddNumbers
				.parallelStream()
				.filter(num -> isCollatzMax(num.longValue(), secondsStart))
				.collect(Collectors.toList());

			results.stream().sorted().forEach(x -> System.out.println(x));
		}
		System.out.println("last number: " + ((1 + (batches) * threads) - 1));
	}