How to round up on a log10

Question

This Go code gives me an error stating that operation ^ is not defined on a float64

10 ^math.Ceil(math.log10(5693440))

The number I'm passing to math.log10 is an int. What am I doing wrong in this function? (Please note, I don't understand Math)

Note, if it helps provide clarity, I'm trying to create a function in Go that does something similar to d3.js scale.ticks() function, which creates values for a Y axis of a graph. The idea behind the above Go code is that I could divide the result of 10 ^math.Ceil(math.log10(5693440)) by 5 and then multiply to create ticks for a Y axis of a graph

Answer 1

The ^ operator is documented in the Go spec under Arithmetic_operators as

^    bitwise XOR            integers

This is neither exponentiation nor does it operate on floats.

Both math.Log10 and math.Ceil take a float64 and return a float64, so you are working with floats even if you think your argument to math.Log10 is an integer (it is a constant so converted for you).

For exponentiation, use math.Pow:

func Pow(x, y float64) float64

Pow returns x**y, the base-x exponential of y.

i.e.

math.Pow(10, math.Ceil(math.Log10(5693440)))

Note that math.Pow returns a float64 as with the other math functions you used.