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58 lines
2.4 KiB
ReStructuredText
58 lines
2.4 KiB
ReStructuredText
.. namespace:: units
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glide_computer
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==============
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This example presents the usage of:
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- different kinds for length, time, and velocity,
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- quantities text output formatting,
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- the use of quantity kinds to show how to handle 3D space for aviation needs,
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- `quantity_point_kind` to mark "absolute" values like ``altitude`` (as opposed to ``height``).
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The use of `quantity_kind` and `quantity_point_kind` provide strong typing
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that divide quantities and quantity points to the ones on a horizontal (X, Y) plane and vertical (Z) axis.
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Their purpose is to make different kinds of quantity
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(i.e. length) separate strong types (i.e. distance, height).
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Additionally, separating a quantity from its quantity point
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means that we can define a ``height`` and ``altitude`` as different strong types.
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A quantity point provides a more restricted interface meant for absolute calculations.
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.. literalinclude:: ../../example/glide_computer.cpp
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:caption: glide_computer.cpp
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:start-at: #include
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:end-before: // custom types
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:linenos:
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:lineno-match:
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The next part of the example defines strong types used by the glide calculator engine. For example
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we have 3 :term:`kinds of quantities <kind>` for a quantity of length:
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- ``distance`` - a relative horizontal distance between 2 points on Earth
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- ``height`` - a relative altitude difference between 2 points in the air
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- ``altitude`` - an absolute altitude value measured form the mean sea level (AMSL).
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For the last case a custom text output is provided both for C++ output streams and the text formatting
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facility.
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.. literalinclude:: ../../example/glide_computer.cpp
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:caption: glide_computer.cpp
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:start-at: // custom types
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:end-before: // An example of a really
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:linenos:
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:lineno-match:
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The engine of this simple glide computer works on quantities of the SI units with a floating-point
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representation. The user can pass any unit valid for a given quantity and the library will automatically
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convert it to the one required by the engine interface.
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The glide calculator estimates the number of flight phases (towing, circling, gliding, final glide) needed
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to finish a task and the duration needed to finish it while flying a selected glider in the specific weather
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conditions.
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.. literalinclude:: ../../example/glide_computer.cpp
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:caption: glide_computer.cpp
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:start-at: // An example of a really simplified tactical glide computer
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:linenos:
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:lineno-match:
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