round

There is another function named ‘round()’ with 1 argument (see here).

round, function

def pure round(quantity: number, digits: number): number

Return ‘quantity’ rounded to ‘digits’ precision after the decimal point. Values are rounded to the closest multiple of 10 to the power minus ‘digits’. If two multiples are equally close, rounding is done toward the even choice.

Example

show table "" with
  round(4.33, 0) 
  round(4.33, 1) 
  round(4.33, 2)  

This outputs the following table:

Remarks

Calling ‘round(x)’ or ‘round(x, 0)’ gives identical results.

Rounding method

The rounding method used here is called the bankers’ rounding (see wikipedia)..

Conversion to Float32

The conversion to Float32 numbers used in Envision (see here) can alter the rounding method. For instance, 0.05 is converted to 0.0500000007 in Float32, and thus ‘round(0.05,1)’ in Envision will return 0.1 when the expected result was 0.0.

Gradient

The gradient associated to ‘round()’ is 1, instead of 0, as the mathematical definition would suggest. The purpose of this irregular behavior is to facilitate the design of discrete policies.

Recipes and Best Practices

If you want to round numbers displayed in tiles, you should not use the ‘round()’ function but rather stylecode ‘precision’ or ‘minPrecision’.

See also

• roundNext
• floor
• ceiling