Update MersenneTwisterEngine template signature to match C++11 standard#14
Merged
9il merged 3 commits intolibmir:masterfrom Jan 7, 2017
Merged
Update MersenneTwisterEngine template signature to match C++11 standard#149il merged 3 commits intolibmir:masterfrom
9il merged 3 commits intolibmir:masterfrom
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This test checks the 10,000th variate generated from Mt19937_64 when seeded with the default seed 5489. See e.g. http://en.cppreference.com/w/cpp/numeric/random/mersenne_twister_engine for spec on the expected 10,000th value.
This patch reworks the existing Mersenne Twister template parameters to match the names and types specified in the C++11 standard, replacing `Uint` with `UIntType` and `uint` with `size_t`. Besides bringing the design closer to the C++11 standard, these changes also reduce ambiguity: `Uint` as a type name is visually easy to confuse with `uint`, which can lead to typos and confusion about intentions. `UIntType` may be more verbose, but it is much clearer in meaning and intent. Ordering and placement of the parameters in the specific 32- and 64-bit instantiations of the template has been updated to match the standard.
In the C++11 standard the 'initialization multiplier' `f` is included as one of the template parameters, since the correct choice of value does not depend solely on the unsigned integer type used.
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@9il I'm submitting this PR among other things because I think these changes will create an easier basis from which to address the issues raised in dlang/phobos#5011 (comment) (it means we can more easily make a direct comparison of behaviour to C++11 implementations). |
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Thanks @WebDrake ! |
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You're welcome. Give me a few minutes and I'll write up an issue on the seeding/word size issue mentioned in the Phobos PR. |
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The original template signature diverges from the C++11 standard both in names and types of template parameters. While not producing a functional difference, matching the standard allows for a less ambiguous declaration and makes for easier adaptation on the part of users used to C++ code.
These patches also introduce the previously-missing "initialization multiplier" template parameter
f. Since the correct value for this parameter is not solely dependent on the unsigned integer type in use, the originalstatic ifwould not have covered all possible instantiations of the generator.Finally, a basic unittest has been added for
Mt19937_64both to validate the generator and ensure that its behaviour does not change as a result of these updates.