Fibonacci sequence by recursive algorithm fail

04202015, 06:42 PM
(This post was last modified: 04212015 02:27 PM by compsystems.)
Post: #1




Fibonacci sequence by recursive algorithm fail
The Fibonacci sequence by recursive algorithm fail in program type CAS, why?
http://en.wikipedia.org/wiki/Fibonacci_number HPPrime CAS CODE Code:
fibo(16) → "Error: Bad argument count" HPPrime NUM CODE Code: EXPORT fibo(n) TI68K CODE Code:
other algorithms http://www.hpmuseum.org/forum/thread316...=Fibonacci 

04202015, 07:57 PM
(This post was last modified: 04202015 07:57 PM by Tim Wessman.)
Post: #2




RE: Fibonacci sequence by recursive algorithm fail
The CAS is case sensitive. There is no function or keyword called "Return"
Code:
TW Although I work for the HP calculator group, the views and opinions I post here are my own. 

04202015, 09:26 PM
(This post was last modified: 04202015 09:43 PM by compsystems.)
Post: #3




RE: Fibonacci sequence by recursive algorithm fail
catalog shows only one, in capitals RETURN, plus the code with tabulation fails, but left aligned says that syntax OK, but fails to run again.
Who has run successfully? Please improve part of tabulation (compiler) 

04202015, 09:58 PM
(This post was last modified: 04202015 10:01 PM by Didier Lachieze.)
Post: #4




RE: Fibonacci sequence by recursive algorithm fail  
04202015, 11:45 PM
Post: #5




RE: Fibonacci sequence by recursive algorithm fail
TIM and compsystems:
The program runs fine using RETURN (i.e., in capitals). Be sure to put the ; as mentioned by Didier. Bill_G 

04212015, 12:25 AM
Post: #6




RE: Fibonacci sequence by recursive algorithm fail
I think that one other thing to take into account is that, for the CAS function, the recursive function calls setting (CAS settings, page 2, line 3) must be set to a number at least that of the parameter value n in fibo(n). Default setting seems to be 9, to fibo(10) returns "Running non recursive evaluator."


04212015, 05:13 AM
Post: #7




RE: Fibonacci sequence by recursive algorithm fail  
04212015, 05:49 AM
Post: #8




RE: Fibonacci sequence by recursive algorithm fail
(04202015 07:57 PM)Tim Wessman Wrote: The CAS is case sensitive. There is no function or keyword called "Return" Font type differentiation of names is a trap that catches all practitioners. 

04212015, 01:57 PM
Post: #9




RE: Fibonacci sequence by recursive algorithm fail
I think a case could be made that a CAS program is not a good construct for this kind of algorithm. Personally, I think that CAS programs are better suited for CAS exclusive purposes (remaining within the CAS environment).
I get that recursive activity is the point of this presentation, but the steps involved are better implemented in a Home program, rather than a CAS variable. The CAS approach, in this case, is a bit like building a pipeline to a beer brewery across town, rather than just using containers to get the desired beer home. Here is a simple means to the same end, which can be embellished as necessary, or if needed as a subroutine, all the while avoiding CAS restrictions : Code:


04212015, 02:20 PM
(This post was last modified: 04212015 03:31 PM by compsystems.)
Post: #10




RE: Fibonacci sequence by recursive algorithm fail
Sorry for my bad English
I found the real problem, works well (CAS PROG) if everything is written in lowercase or all uppercase and, in single shift and does not work (if then else end → If Then Else End) HP TEAM must review the compiler (CAS PROG) for next versión of firmware, the following code is successfully compiled, but fails to run, you must verify that the commands are well written Code: #CAS fibo_cas(16) → "Error: Bad argument count" ? What affects capitalized If, the algorithm?  I found a serious problem, if two functions prog HOME or prog CAS, has the same name appears only version HOME. The only solution is to support working directories for next versión of firmware (DIR nameDir .... EndDir) do you agree? PROBLEM WITH TWO FOLLOWING CODES, try it yourself Code: #CAS Code: export fibo(n)  OK codes Code: #CAS fibo_cas(16) → 987.0 Code: export fibo_home(n) Or Code: export fibo_home2(n) (04212015 01:57 PM)DrD Wrote: I think a case could be made that a CAS program is not a good construct for this kind of algorithm. Personally, I think that CAS programs are better suited for CAS exclusive purposes (remaining within the CAS environment). Just to use one type CAS program if the output is symbolic is obligatory, if only numerical output is optional For example the following code can not code as HOME program Code: #CAS a tip, if the return command have parentheses, returns the output is in exact format, otherwise the approx Code: #CAS 

04212015, 04:00 PM
Post: #11




RE: Fibonacci sequence by recursive algorithm fail
(04212015 02:20 PM)compsystems Wrote:(04212015 01:57 PM)DrD Wrote: I think a case could be made that a CAS program is not a good construct for this kind of algorithm. Personally, I think that CAS programs are better suited for CAS exclusive purposes (remaining within the CAS environment). For me it is not completely clear what you are trying to do. However, I synthesized your larger program into just this fragment, which (I think) is what you may be asserting, and it IS in HOME mode. The general idea is interaction with string / expression / number. You can accomplish the rest of your program with similar workflow: Code:


04222015, 02:37 AM
Post: #12




RE: Fibonacci sequence by recursive algorithm fail
(04212015 01:57 PM)DrD Wrote: I think a case could be made that a CAS program is not a good construct for this kind of algorithm. Personally, I think that CAS programs are better suited for CAS exclusive purposes (remaining within the CAS environment). I get that recursive activity is the point of this presentation, but the steps involved are better implemented in a Home program, rather than a CAS variable. The CAS approach, in this case, is a bit like building a pipeline to a beer brewery across town, rather than just using containers to get the desired beer home. Actually, CAS is REQUIRED for calculating Fibonacci numbers with more than 12 digits. CAS supports integers of almost unlimited length. Home is limited to a mere 12 digits. <0ɸ0> Joe 

04222015, 10:20 AM
Post: #13




RE: Fibonacci sequence by recursive algorithm fail
(04212015 01:57 PM)DrD Wrote: Here is a simple means to the same end, which can be embellished as necessary, or if needed as a subroutine, all the while avoiding CAS restrictions : Fibonacci numbers and the factorial are different, aren't they? Marcus von Cube Wehrheim, Germany http://www.mvcsys.de http://wp34s.sf.net http://mvcsys.de/doc/basiccompare.html 

04222015, 12:41 PM
Post: #14




RE: Fibonacci sequence by recursive algorithm fail
Quite right.
Code:


04232015, 02:21 AM
Post: #15




RE: Fibonacci sequence by recursive algorithm fail
Code: #CAS nfibo_cas(28) → 317811 nfibo_cas(30) → BUSY → 832040 nfibo_cas(100) → running non recursive evaluator What means the above output? nfibo_cas(100) → ¨ERROR MEMORY¨ (ti68k calcs) 

04232015, 06:44 AM
Post: #16




RE: Fibonacci sequence by recursive algorithm fail
If you run a recursive program, at each recursive call, the environment is saved on a stack. But this stack can not grow dynamically, therefore if you want to do more embedded recursive calls, you must change the way evaluation is done (and save environment in the heap).


04232015, 02:09 PM
Post: #17




RE: Fibonacci sequence by recursive algorithm fail
but better display a message that says, ¨stack overflow¨ or something similar.
I consider it a BUG that the program editor, says that the compilation was successful without checking the syntax of each command, each are sensitive to lowercase and uppercase, I took a long time to detect that had to write, If Then End as if then end or IF THEN END 

04232015, 06:58 PM
Post: #18




RE: Fibonacci sequence by recursive algorithm fail  
04242015, 08:37 PM
(This post was last modified: 04242015 08:37 PM by compsystems.)
Post: #19




RE: Fibonacci sequence by recursive algorithm fail
¨Runtime Error: Maximum recursion depth (stack) exceded¨
Who proposes another best output message? 

04252015, 06:12 AM
Post: #20




RE: Fibonacci sequence by recursive algorithm fail
No, because running non recursive evaluator is not a runtime error, your program will still run (it will run slower).
You can't expect a recursive Fibonacci program to finish with n=100 (unless you have some remember table), because the time required is proportionnal to Fibonacci(100) that's about 1e20. 

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