Math.pow floating point issues

[joshkeys19]

Hi everyone!

I’ll keep this short and sweet. It seems that if you raise a static value to a floating point exponential, it works fine. But if you use variable, and raise it to an exponential, it converts the exponent to an integer:

The code “on button A pressed”, will just compute y^1 as the 1.3 is rounded down to 1.
The code “on button B pressed”, will compute 40^1.3 as I would like.

I have tried multiplying y by 1.0. I’ve tried converting 1.3 to a string then using parseFloat to bring it back, just about everything I can think of to force it to not round. It seems a strange bug. Any ideas?

Thanks,
Josh

[joshkeys19]

Hi again everyone,

I’d like to clarify one important point here. The simulator will get this correct, but if you run it on the micro:bit, it will not work. Also the screenshot I put above will try and square a negative number if you press A on the simulator, so I’ve changed it to “strength”:

In case you want to copy the code directly to your javascript:

let y = 0
let x = 0
input.onButtonPressed(Button.A, function () {
    y = input.acceleration(Dimension.Strength)
    x = y ** 1.3
    basic.showNumber(y)
    basic.showNumber(x)
})
input.onButtonPressed(Button.B, function () {
    y = 1023
    x = y ** 1.3
    basic.showNumber(y)
    basic.showNumber(x)
})

Remember, this works in the simulator, but NOT in hardware (on the micro:bit)

Thanks,
Josh