GY-63_MS5611/libraries/randomHelpers

randomHelpers

Arduino library for faster generation of random numbers.

Description

This library contains functions that have the goal to deliver random bits faster than the build in random function can, while still using it.

The idea is to have a buffer ( __randomBuffer) which can hold up to 32 bits. When a number of random bits are needed, these are first fetched from the buffer and if the buffer gets empty, it is filled again with a call to the random generator.

This strategy works well with a 32 bits buffer and requests for 1..16 random bits. However above 16 bits the overhead is larger than the gain. So to improve in that range too one could use a faster random function like the one from Marsaglia (included).

Note the gains differ per platform and are more explicit on the Arduino UNO platform than on an ESP32.

Interface

functions implemented are

• uint32_t Marsaglia() fast PRNG.
• bool seedMarsaglia(uint32_t a, uint32_t b) seed the Marsaglia PRNG. a and b should not be 0. returns true on success.
• bool getRandom1() returns 0 or 1, false or true.
• bool flipCoin() A wrapper around getRandom1().
• uint8_t getRandom4() returns 0 .. 15.
• uint8_t getRandom5() returns 0 .. 31.
• uint8_t getRandom6() returns 0 .. 63.
• uint8_t getRandom8() returns 0 .. 255 typically a byte.
• uint16_t getRandom16() returns 0 .. 65535 (2 bytes).
• uint32_t getRandom24() returns 0 .. 16777215 (3 bytes), e.g. random RGB colour.
• uint32_t getRandom32() returns 0 .. 2^32 - 1 (4 bytes) this is the core random generator
• uint64_t getRandom64() returns 0.. 2^64 - 1 (8 bytes).
• uint32_t getRandomBits(n) returns 0.. 2^n - 1 This works well for 1..16 bits but above 16 it is slower than the standard way.
• uint8_t throwDice() returns 1..6.

The examples show how to use these and how their performance gain relative to calling random() for every random number.

Operation

See examples

Future

• improve performance getRandomBits(n) for n = 17..31
• investigate new tricks :)
• wrap all up in a class.
• test if the functions are uniform.