Formula: Errors

QFFE_211: "Invalid 'log' argument : 'value'"

Natural logarithm of the argument can not be calculated.

Cause

• Argument value is not positive

  log(t+1)	Invalid 'log' argument : '0' for t = -1
  log (-asin(-1))	Invalid 'log' argument : '-270'

• Argument value becomes zero or negative due to rounding errors

  log(1 + 1e-20 - 1)	Invalid 'log' argument : '0'
  log(1 + 1e-20 - 1 - 1e-30)	Invalid 'log' argument : '-1e-030'

Resolution

• Check that the value of logarithm argument is always positive.
• If the cause is in rounding errors, try to change the order of operations to reduce their impact.