[PHOENIX-2019] Implement Build-in math function ln and log

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.5.0
• Assignee: Shuxiong Ye
• Reporter: Shuxiong Ye
• Created: 30/May/15 18:59
• Updated: 21/Nov/15 02:16
• Resolved: 16/Jun/15 00:21

Description

Implement math build-in function, ln and log. Example show as below:

ln(dp) natural logarithm ln(2.0) 0.693147180559945
log(dp) base 10 logarithm log(100.0) 2
log(b, x) numeric logarithm to base b log(2.0, 64.0) 6.0000000000