graphing IFTE with ROM 2.15
in [HP48]
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From: John H Meyers on 12 Sep 2009 18:19 On Sat, 12 Sep 2009 14:09:50 -0500, Wes wrote: >> Re 'IFTE(X<1,X,X^2)' STEQ ERASE DRAX DRAW PICTURE >> >> > Bug in 2.15 confirmed ["IFTE Error: Bad Argument Type"] >> >> Was already present in 2.10, with VER -> 4.20060919 >> How is it in BP's version? >> VER in 2.09 is 4.20060602 >> What's VER in 2.15? > 4.20060919 as well. > > I may have to go back to 2.09 on this one. > The ability to graph piecewise functions is pretty important for me. None of the following "bugs out": \<< 'X<1' 'X' 'X^2' IFTE \>> \<< IF 'X<1' THEN 'X' ELSE 'X^2' END \>> '(X<1)*X+(X\>=1)*X^2' It's too bad, however, that you have to choose a version, according to which bugs bug you less :) Since ROM updates are now pretty easy and fast, you could also hop back & forth, like the bugs bunny :) [r->] [OFF]
From: Wes on 13 Sep 2009 05:38 On Sep 13, 1:19 am, "John H Meyers" <jhmey...(a)nomail.invalid> wrote: > None of the following "bugs out": > > \<< 'X<1' 'X' 'X^2' IFTE \>> > > \<< IF 'X<1' THEN 'X' ELSE 'X^2' END \>> > > '(X<1)*X+(X\>=1)*X^2' > > It's too bad, however, > that you have to choose a version, > according to which bugs bug you less :) > > Since ROM updates are now pretty easy and fast, > you could also hop back & forth, like the bugs bunny :) I have my TI-83+/84+ students use the '(X<1)*X+(X>=1)*X^2' trick. Just seems a shame not to be able to use algebraic IFTE as intended. The TI-Nspire has a true piecewise function entry with curly brackets and all, like an algebraic CASE statement. IFTE() functions also fail with TABLE as well with rom 2.15. Even with 2.09, IFTE doesn't work with the grapher's F' command which graphs the derivative, although taking the derivative on the stack works properly. The IFTE is an interesting function. If you define 'F(X)=SIN(X)', then F(Z) evaluates to 'SIN(Z)'. But if 'F(X)=IFTE(X<1,2*X,X+3)', then F(Z) will result in 'IFTE(Z<1,2*X,X+3)|(X=Z)' where the X's are local variables (LAM). If you edit this expression with EQW with no changes, the local X's change into global X's (ID X). Using <Left Shift - Down Arrow> to edit instead also results in globals X's, but with a different "coding". Look at it with EMACS or NOSY to see what I mean. -wes
From: Wes on 13 Sep 2009 06:04 On Sep 13, 12:38 pm, Wes <wjltemp...(a)yahoo.com> wrote: > IFTE() functions also fail with TABLE as well with rom 2.15. Interestingly, there appears to have been similar IFTE problems with the hp49g. Doing a search for: IFTE table bug pulls up some similar posts from 2002 and before. http://groups.google.com/groups/search?&q=IFTE+table+bug+group%3Acomp.sys..hp48 Any connection? -wes
From: hgabert on 13 Sep 2009 17:30 On Sep 13, 4:04 am, Wes <wjltemp...(a)yahoo.com> wrote: > On Sep 13, 12:38 pm, Wes <wjltemp...(a)yahoo.com> wrote: > > > IFTE() functions also fail with TABLE as well with rom 2.15. > > Interestingly, there appears to have been similar IFTE problems with > the hp49g. Doing a search for: IFTE table bug > pulls up some similar posts from 2002 and before. > > http://groups.google.com/groups/search?&q=IFTE+table+bug+group%3Acomp.... > > Any connection? > > -wes Just enclose the algrebraic expression in program delimiters, i.e., \<< 'IFTE(X<1,X,X^2)' \>> or append an EVAL for good measure, i.e., \<< 'IFTE(X<1,X,X^2)' EVAL \>> and it works. (Can't wait for the totally bug-free version 2.16, the mother of all ROM updates, the last one we'll ever need!)
From: TW on 13 Sep 2009 19:03
> (Can't wait for the totally bug-free version 2.16, the mother of all > ROM updates, the last one we'll ever need!) Hah? It is extreeemly difficult to make any changes to the ROM. Most banks are completely full *to the bit*. In other words, if you want to fix something and to do so you need to add a single sysRPL comman (1 nibble), you will have to find a place nearby that you can edit to save a nibble and that won't shift anything out of place. If you shift it at all, the calculator will come crashing down. There isn't lack of desire to fix and add things, but rather making any changes takes WAY too long and quickly becomes an exercise in frustration. TW |