abs -- absolute value function

• Usage:

  abs x

  abs I

• Inputs:
  • x, a real number or a complex number,
  • I, a real interval or a complex interval,
• Outputs:
  • a real number, the absolute value of x
  • a real interval, an interval containing the absolute values of all the points of I

i1 : abs(-pi)

o1 = 3.141592653589793

o1 : RR (of precision 53)

i2 : abs(1+ii)

o2 = 1.414213562373095

o2 : RR (of precision 53)

i3 : abs(interval(1,2))

o3 = [1,2]

o3 : RRi (of precision 53)

i4 : abs(interval(1+2*ii,3+4*ii))

o4 = [.9999999441206455,5.000000018626451]

o4 : RRi (of precision 53)