(Bug?) HP48 Equation Library

03062017, 05:31 PM
(This post was last modified: 03062017 06:54 PM by Han.)
Post: #35




RE: (Bug?) HP48 Equation Library
Well, I eventually did find an actual bug (or perhaps limitation) of the HP48 MES. According to this patent:
https://www.google.com/patents/US5175700 the MES basically automates the process of substituting in known values, and finding an equation that has only one unknown, solving that equation, then repeating the process after updating its list of known/solved values. The problem with this is that an inconsistent system shows up as having a solution. For example: Code: { 'X+Y=10' 'X+Y=11' } STEQ 1 'X' STO MINIT MSOLVR Proceed to solve for Y and the HP48 produces: Searching... Solving for Y... Y:9 Zero Except X=1 Y=9 is only a zero of the first equation. There is no check at all whether that solution is in fact a solution to the system. I only noticed this when I started working on a hybrid solver engine that mimics the Multiple Equation Solver (MES). In the meantime, I'm still interested in the formulas for the silicon density of states equations in the immediately previous post. Graph 3D  QPI  SolveSys 

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