Code Fragments and Useful Routines
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x.x That's totally correct... I thinking... idk what I was thinking Razz

But that's correct Smile I would rather do
[cpde]repeat Ans=2[/code]
simply because it seems more accurate to do so... idk. I'm going to edit my code to make it correct
http://tanner.myserverathome.com
I'm with Mufin; just start the timer, run a massive number of iterations, and hope it all evens out.
Geopipe
I dunno... I have done something like:

Code:
Starttimer->K
For(A,0,1000
<code>
End
checktimer(K

and it has returned between +/- 2 seconds, which for me is too much. Where as my routine, it always returns the same thing, else it will more often than not return the right thing Smile
http://tanner.myserverathome.com
I understand why you're doing that, so I encourage you to keep using that method, especially when you want to evaluate exactly how much faster a method is than another. For my purposes, usually discovering qualitatively which one is faster is good enough.

And Mufin, nice avatar!
Geopipe
*bump* I'm not sure if this has previously been posted.

Modulus Operator

A%B, A mod B, or mod(A,B) (three different ways to represent the modulus of A base B) can be calculated as follows:


Code:
int(BfPart(A/B))


Note that A and B should ideally be integers, and that the outermost int() is necessary to remove some corner cases where the result may appear to be an integer but may have a very small floating point component (specifically, < 10^-10) in the calculator's memory.

Edit: Thanks to PT_ for catching a typo in this post.
Geopipe
KermMartian wrote:
*bump* I'm not sure if this has previously been posted.

Modulus Operator

A%B, A mod B, or mod(A,B) (three different ways to represent the modulus of A base B) can be calculated as follows:


Code:
int(AfPart(A/B))


Note that A and B should ideally be integers, and that the outermost int() is necessary to remove some corner cases where the result may appear to be an integer but may have a very small floating point component (specifically, < 10^-10) in the calculator's memory.


It's been done, except the other guy's method made use of the round( command.
Have fun!
Ah, cheers, thanks for looking. I posted this because Sonlen needed a modulo operation for displaying HH:MM:SS from seconds.
Geopipe
Here's a small (3 line) base-N to decimal converter.

Code:
Input N
Input Str1
sum(seq(inString(sub("123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",1,N),sub(Str1,A,1)),A,1,length(Str1))seq(N^A,A,length(Str1)-1,0,~1->B

I'm still working on a small decimal to base-N converter.
Very nice use of Seq()! I did something very similar with a pair of For() loop for my base converter, but your seq tricks reduce my seven-line implementation to one. Smile Impressive.
Geopipe
Here's my new base-N to base-M converter (total of 16 lines long):

Code:
Input "FROM BASE:",N
Input "TO BASE:",M
Input "",Str1
sum(seq(N^A,A,length(Str1)-1,0,~1)seq(inString(sub("123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",1,N),sub(Str1,A,1)),A,1,length(Str1->B
Pause B
seq(0,A,1,int(log(B)/log(M->L1
While B
int(log(B)/log(M->C
int(BM^~Ans->L1(dim(L1)-Ans+1
B-AnsM^C->B
End
" ->Str1
For(A,1,dim(L1
Str1+sub("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",1+L1(A),1->Str1
End
DelVar L1sub(Str1,2,length(Str1)-1->Str1

The decimal to base-M converter was unfortunately longer than I had hoped for. The last 5 lines I knew would be needed, but I was hoping to get the 6 lines that make the list that stores all the number data to work just fine in 1 or 2 lines. Either way, it's still a huge improvement on my previous one.
How about
Code:
int(BM^~Ans->L1(dim(L1)-Ans+1
to
Code:
int(BM^~Ans->L1(1-Ans+dim(L1
? Saves a byte. Smile
Geopipe
I think one of your statements might be subject to rounding error:

Code:
int(log(B)/log(M->C


That will fail in some cases, for example, int(log(16)/log(2))=3 instead of 4 because log(16)/log(2)=3.9999999999999

This code, which I believe is only one byte extra, should fix this problem:

Code:
int(round(log(B)/log(M->C
Ah yes, that failsome problem. An excellent point, that. I was going to suggest a log reduction until I remembered that it's log(a/b) -> log(a) - log(b), not log(a)/log(b) -> log(a-b).
Geopipe
KermMartian wrote:
How about
Code:
int(BM^~Ans->L1(dim(L1)-Ans+1
to
Code:
int(BM^~Ans->L1(1-Ans+dim(L1
? Saves a byte. :)


:P I wasn't much looking for line-by-line optimizations. I literally made this code in about 30 minutes this morning, after a kid who was asking for help with his binary-decimal converter gave me an idea.

calc84maniac wrote:
I think one of your statements might be subject to rounding error:

Code:
int(log(B)/log(M->C


That will fail in some cases, for example, int(log(16)/log(2))=3 instead of 4 because log(16)/log(2)=3.9999999999999

This code, which I believe is only one byte extra, should fix this problem:

Code:
int(round(log(B)/log(M->C


Noted and updated.

KermMartian wrote:
Ah yes, that failsome problem. An excellent point, that. I was going to suggest a log reduction until I remembered that it's log(a/b) -> log(a) - log(b), not log(a)/log(b) -> log(a-b).


:P I didn't get a 5 on my AP Calc exam to be corrected by a "log reduction" shortcut.
No offense intended, ignore my attempts at optimization. Smile When I see a piece of code that looks extremely well-made my reflex is to try to optimize. As it is, it's very tight code.
Geopipe
KermMartian wrote:
No offense intended, ignore my attempts at optimization. Smile When I see a piece of code that looks extremely well-made my reflex is to try to optimize. As it is, it's very tight code.
Haha, no worries. Thanks for the compliment. Good to see that the countless hours I spent learning to optimize my code hasn't been wasted. Smile
MufinMcFlufin wrote:
KermMartian wrote:
No offense intended, ignore my attempts at optimization. Smile When I see a piece of code that looks extremely well-made my reflex is to try to optimize. As it is, it's very tight code.
Haha, no worries. Thanks for the compliment. Good to see that the countless hours I spent learning to optimize my code hasn't been wasted. Smile
Not at all; you write much better code than many of your peers.
Geopipe
I edited the first post with a list of routines I found in this topic. Parts where people helped others or optimized code, then I added you to the "Author" list (which is the part after the code). If you find any parts where I messed up (I know there are a lot, I went into a new method as I got through all of them, so I need to edit the top parts.) I went along the convention of
Code:
[b][size=18]Title[/size][/b]
[i]Inputs:
A = A number
Str1 = A string
Outputs:
A = Another number[/i]
[code]Code here!
Wee!1!!
Moar code!!![/code]
[i]Author(s)[/i]
If I found any parts that were combined outputs (AKA, Ans and Str1 equal a string), then I did "Ans & Str1 = A string" If I didn't get a name right, or there was better code posted that I missed, tell me Smile
http://tanner.myserverathome.com
Oh, I should add this to the list before I forget about it entirely.

Compact Triangle Edge-Length Solver (Pythagorean Theorem)

Given
1) side-lengths A, B, and C, where C is the hypotenuse, and
2) the one side of unknown length being set to "0"
The length of the unknown side is


Code:
:C²-B²-A²
:√(Ans-2Ansnot(C


Fairly trivial, but (imho) fairly well-optimized Smile
Tanner, you are most awesome! I have an idea: Do you guys have an interest in working together to make a compendium of useful BASIC routines and release it here and on ticalc.org.
Geopipe
  
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Code Fragments and Useful Routines
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