On 02/12/2007 07:24 PM, Dave Perry wrote: > This looks really slick,
:-) > ... why is this patch good above the troposphere (> 100,000 ft.)? It > should give the same answer as the last patch, only much more > efficiently. The tabulated numbers come from a three-layer model, namely layers 0 through 2 as defined in the table at the front of this reference: http://www.av8n.com/physics/altimetry.htm See also references therein. You can check the foregoing assertion by looking at the table-entries at the critical (layer-boundary) altitudes. Yesterday's effort used only layer zero, which is why it was valid only within the troposphere, 36000 ft MSL and below. [snipped several more questions, all with the same answer] > As was pointed out, once you are above the "transition zone", S = 29.92 > and C(S) = 0. How about an "if" to avoid the second interpolation in > this case? As you also pointed out, why not just cache P(S) and re-use it in the overwhelmingly likely case that S is unchanged since last time? > I am glad you changed your mind! It wasn't much of a change. My previous point was that /small/ changes were a waste of time; making yesterday's code 2x faster would have been a total waste. I also haven't changed my mind about the following: > What I am proposing is to create a C++ function (say height_ft) that has > two arguments, P0 and P1 that does the interpolation in John's new patch > using his constants. That is the same spirit as what I was suggesting in the opening paragraphs of: http://www.av8n.com/fly/fgfs/README.altimetry.html > When will you put this in cvs? Ha, funny joke. ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
