FLE

Arduino library for Arduino library for float with error datatype

Description

This experimental library provides basic math when have a quantity with a certain error margin. E.g. when you approximate PI as 22/7 it is not exact. By doing the math with FLE's one can see how much error adds up in an calculation.

Interface

Printable

The FLE class implements the public interface of Printable. This allows you to print an FLE in human readable form.

    FLE x(3.14, 0.002);
    x.setDecimals(4);
    Serial.println(x);                 // will print 3.1400 ± 0.0020
    Serial.println(x.setDecimals(2));  // will print 3.14 ± 0.00
    Serial.println(x.value());         // will print 3.14

When the ± char does not print correctly, one could change the font.

Functions

FLE(val = 0, err = 0) constructor, with default value and error set to 0.
PrintTo(Print& p) printable interface, define a stream to pritn to.
Format is "val ± err" see above (plusminus = char(0177))
setDecimals(n) will print the FLE bot val and err with n decimals.
setSeparator(char c) overrules the standard ± char. (0177)
value() returns val part
error() return err part
relError() returns relative error, except when val == 0. Then it return 0. Q: should this be "NaN
high() returns val + error margin (= max real value)
low() returns val - error margin (= min real value)

furthermore the basic math is implemented, "+, -, *, /, +=, -=, *=, /="

Todo

comparison (investigate, what means equal or less than ..)
functions log, exp,
functions sqr, sqrt, pow
functions sin, cos, tan (+ inverse + hyp)
test ad infinitum
option to set the ± char for platforms that cannot print it.
test negative numbers
test large / small numbers.
test other separator
more demo sketches...

Operation

negative numbers not tested yet

See example

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FLE