Bisection Search Like A (Human) Boss

Bisection search, or binary search for us developers, is a technique for finding the best value within a given range of values.

┬áTechnically speaking, Wikipedia says the “bisection method in mathematics is a root-finding method that repeatedly bisects an interval and then selects a subinterval in which a root must lie for further processing.”

This post describes tips for when you need to bisection search manually by hand (by “feel”), as opposed to when it can be automated by, say, a computer algorithm.

For example, say you’re very thirsty and need water fast so you pour yourself a glass of water: Pour too fast and it spills but too slow and it takes too long. You want to pour fast enough to quench your thirst as soon as possible but not so fast that it spills. The speed of pouring is your range of values (eg. slow to fast) and the consequences of the speed of pouring (how long it takes and if it spills) are your criteria to decide the best value. You try pouring the glass slowly and it’s too slow: Pour faster. You try pouring the glass faster and it spills: Pour slower but faster than the first time. You try pouring the glass “just right”: It’s fast enough and doesn’t spill. You’ve found the best pouring speed by bisection search!

Update 2020-10-04: Added link to Bisection Search Calculator Spreadsheet

Older updates are archived at the bottom under the Updates section.

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iRacing Force Feedback Settings

Update 2017-01-02: I’m now updating FFB information over on my Secrets of iRacing post.

Update 2015-02-26: I’ve been changing up my FFB settings in iRacing lately after realizing that linear ffb resulted in such low force strengths (to avoid clipping) that I wasn’t really feeling the road anymore. The ffb changes were just too subtle. So, because I have a low-end wheel, a G27, I’m now using non-linear ffb and doing the usual binary-search to find the optimal force strength to avoid clipping. I’m doing this only because of my relatively low-end, entry-level G27. I expect the recommended usage for higher strength wheels (T500s/T300s, Fanatec ClubSports, Accuforce Pro, etc.) should still use linear ffb.

Update 2015-02-26 – 2: For the record, a binary search is one where you take your current value, determine whether it’s too little or too much, and then double it (when too little) or halve it (when too much), and repeat that process at each new level to dial in on your optimal value. For example, for iRacing force strengths I might start out at 32, decide that’s too much and go to 16 (half of 32), decide that’s too little and go to 24 (16 + 8 which is half of 16), decide that’s too much and go to 20 (24 – 4 which is half of 8), decide that’s too little and go to 22 (20 + 2 which is half of 4), decide that’s too little and go to 23 (22 + 1 which is half of 2), decide that’s too much and go to 22.5 (22 – 0.5 which is half of 1). This is a real example I just did in iRacing a few minutes ago on the Mazda MX-5.

Update 2015-02-26 – 3: Nvidia users should check out these threads: iRacing graphic optimizations for NVIDIA users, Guide: nVidia iRacing Antialiasing (AA) Settings, NVIDIA SLI Compatibility results. The second guide about AA gives some good settings for Nvidia Inspector (I use in-game 4x AA with Nvidia Inspector AA – Mode “Enhance” and AA – Setting “8xS [Combined: 1×2 SS + 4 MS]”. Read the thread for what they mean). The third thread is about SLI and getting rid of microstuttering (I use Nvidia Inspector “SLI Compatibility Bits” = “0x00402015” per the thread). It’s not perfect but it’s better than in-game AA and should give higher performance.

iRacing Force Feedback Settings

I’m a big fan of iRacing sim racing and I frequent their forums quite a bit. I’ve seen a number of posts, over time, on the iRacing forums about people asking for the right force feedback settings for their wheels. As it turns out, this info in its complete form is harder to come by then you might think so I’ve decided to post everything I know and have implemented for my Logitech G27 for force feedback in iRacing…

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