HP50G SIMPLEX Version14b Max Min Pivot Algorithm, multiple/unbounded, unfeasible sol
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01-29-2023, 02:54 PM
(This post was last modified: 02-01-2023 02:10 PM by Gil.)
Post: #23
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RE: HP49-50G VERSION 13d.hp SIMPLEX Max Min Pivot Algorithm, multiple/unbounded solutions
Version 13d
Handling of "unfeasible" problem. For visual outlook, deletion of no more used SAME.SOL. Just look at the following problem (input Matrix) : [[ 1 1 'L' 5 ]* [ 0 1 'G' 8 ]** [ 6 4 0 'Max' ]] According to usual SIMPLEX convention (in this program), if nothing is said about xi (here x1 and x2), it is assumed to be >=0. If x2 >= 8 according to **, then * cannot be <0 as said in *, unless breaking the above rule and accepting that x1 might be <= 0 (x1=-3). Put [[ 1 1 'L' 5] [ 0 1 'G' 8 ] [ 6 4 0 'Max' ]] on the stack and launch —>GO. You get then, with the new version 13d: { Var 2¦Steps 4 Time1¦s : Z-Max: 14 :x1: -3 :x2: 8 : Sign { x1 } not allowed: UNFEASIBLE.problem}. Then, pressing afterwards the variable S.1-N, you get also the reminder: :Unfeasible problem Sign incompatibility of { x1 }, [x1 x2... ]: [ -3 8 ] Of course, if you specify that x1 is <= 0 [[ 1 1 'L' 5 ] [ 1 0 'L' 0 ] [ 0 1 'G' 8 ] [ 6 4 0 'Max' ]] and launch —>GO with the new above Matrix, you will get: { Var 2¦Steps 5 Time1¦s : Z-Max: 14 :x1: -3 :x2: 8 }, with no special message. The same applies to [[ 1 1 'L' 5 ] [ 1 0 'F' 0 ] [ 0 1 'G' 8 ] [ 6 4 0 'Max' ]], supposing x1 Free (of unknown sign). |
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