Math abs function does not work with double?

Troubleshooting
1

Hi,

I am working with precise numbers. I have noticed that the abs function, does not work correctly.

void setup() {
  Serial.begin(115200);
}

void loop() {
  double number = 0.000000029166328080224515062468;
  double number2 = abs(number);
  Serial.println(number, 30);
  Serial.println(number2, 30);
  delay(1000);
}

Outputs
0.000000029166328080224520391539
0.000000000000000000000000000000

Is it possible that double has 64 bit, and the abs function is good only for 32 bit numbers?

Thanks!

2

abs is an integer function. Try fabs. That works on doubles.

5 Likes
3

Thank you! Did not know that!

1 Like