GY-63_MS5611/libraries/TOPMIN

TOPMIN

Arduino library to track the top N minima.

Description

This experimental library tracks the top N minima of a series of values.

The library implements two classes:

• TOPMIN just tracks the values. (smaller footprint).
• TOPMINext also tracks a user defined 32-bit tag (e.g. timestamp).

The latter is more useful as it allows to link the top N values to a certain time or day, an index in a database, or another indirect reference. It can even be used to store a second parameter e.g. what was the humidity for the top N temperatures.

The library can be used for different applications:

• track top N minima temperature / humidity over a given period of time.
• track top N UV minima intensity during the day.
• track top N trading volumes or .
• track top N smallest fish caught in a contest.
• track top N minimum number of visitors during a day.

The 32 bit tag, can be filled with a 32 bit number like a timestamp, bit can also be used more creatively e.g. 2x 16 bit numbers or even 32 booleans. Any mapping is possible (but not part of the library).

Links

• https://github.com/RobTillaart/TOPMAX
• https://github.com/RobTillaart/TOPMIN
• https://github.com/RobTillaart/runningAverage
• https://github.com/RobTillaart/MINMAX

Interface

#include "TOPMIN.h"

TOPMIN

• TOPMIN(uint8_t size = 5) Constructor, defines the number of elements it can hold. Default number of elements is 5. If size < 3 it will be set to 3. The maximum size is currently 255.
• uint8_t count() returns the number of elements in the internal array. 0.. size.
• uint8_t size() returns the maximum number of elements in the internal array.
• void reset() reset the internal counter to 0, logical clearing of the system.
• bool add(float value) add a value to the TOPMIN object to check of it needs to be in the top N of minima.
• float getValue(uint8_t index) get an element of the internal array. The index must be <= count(), if not the function currently returns NaN. This may or may not be a valid value, so the user should guard the index parameter carefully.
• bool fill(float value) convenience function to fill the internal array with a single value e.g. 0.

TOPMINext

Derived from TOPMIN, extended with a tag field.

• TOPMINext(uint8_t size = 5) Constructor, defines the number of elements it can hold. Default number of elements is 5. If size < 3 it will be set to 3. The maximum size is currently 255.
• bool add(float value, uint32_t tag) add a value to the TOPMINext object to check if it needs to be in the top N of minima. If so add the 32-bit tag too (at same index). The 32-bit tag is typical an index, counter or timestamp, but any semantic is possible.
• uint32_t getTag(uint8_t index) get the tag from an element of the internal array. The index must be <= count(), if not the function currently returns 0xFFFFFFFF. This may or may not be a valid value, so the user should guard the index parameter carefully.
• bool fill(float value, uint32_t tag) convenience function to fill the internal array with a single value e.g. 0. (tag idem).

Future

Must

• keep functional in sync with TOPMAX.
• improve documentation.
• 0.2.0
  • reverse getValue() / getTag() be
  • index = 0 must be the absolute minima (maxima).
  • if you change size of TOPMIN object the "winner" gets a different index
  • better would be to have to reverse index = count() - index
  • then less code adaptions are needed.

Should

• add unit tests.
  • for the TOPMINext version if possible
• add more examples.
  • example creative use of tag field.
  • example performance measurements (depends on size + inserted values). (Marsaglia PRNG, to be repeatable over platforms).

Could

• create template class.
• bool check(float value) and bool check(float value, uint32_t tag)
  • if (value < getValue(0)) or so.
  • checks if this value would be added to the TOP-N
• TOP class, in which the condition can be set as parameter.
  • a function() returning true or false when comparing 2 values.

Wont

• how to handle double/triple etc. entries with same value
  • they are handled as unique elements, that is what I had in mind.