[SYSTEMDS-1894] Switch log from FastMath to Math

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Done
• Fix Version/s: SystemML 1.0.0
• Assignee: Matthias Boehm
• Reporter: Matthias Boehm
• Created: 06/Sep/17 21:30
• Updated: 21/Sep/17 05:30
• Resolved: 08/Sep/17 19:27

Description

Currently, SystemML uses FastMath instead of Math for certain builtin operations. However, recent experiments with JDK 8 on different platforms have shown that for log this is no longer beneficial and actually leads to a slowdown of up to 30%.

For example, on a scenario of 20 iterations of log(X), where X is a 10K x 10K dense matrix, we obtained the following results:

log w/ FastMath: 85.2s
log w/ Math: 65.6s

Hence, this task aims to replace FastMath.log with Math.log in all occurrences in SystemML runtime and code generation framework.