PARI's commands

[kar_bon]

Originally Posted by science_man_88

wonder how fast each is.
tested both with the equivalent of 36^577-1 and they came up equal.

I've tested both variants with (on older system):

yours: for(x=1,100000,convert(12345678901234567890,10,16)) done in 19.6 secs

mine: for(x=1,100000,convert1("12345678901234567890",10,16)) done in 10.5 secs

The main difference is:

You're using the power function and I only the multiplication:

power: a= x1*b^e1 + x2*b^e2 + x3*b^e3 + ....
multiplication: a= ((x1*b + x2)*b + x3 ...

[science_man_88]

Originally Posted by kar_bon

I've tested both variants with (on older system):

yours: for(x=1,100000,convert(12345678901234567890,10,16)) done in 19.6 secs

mine: for(x=1,100000,convert1("12345678901234567890",10,16)) done in 10.5 secs

The main difference is:

You're using the power function and I only the multiplication:

power: a= x1*b^e1 + x2*b^e2 + x3*b^e3 + ....
multiplication: a= ((x1*b + x2)*b + x3 ...

I knew you'd be better than me in like 2 seconds lol.

[CRGreathouse]

No big deal, he knew Horner form and you didn't.

[science_man_88]

Originally Posted by CRGreathouse

No big deal, he knew Horner form and you didn't.

he should put his up, yeah I had no power this morning but it's back up now I'm kinda worried my mom supposedly had hypercapnia last night and they think codeine ( methyl-morphine) may have helped it unsurprising with morphine allergies in the family history. I know more terms than my sisters so I can describe it but I haven't gone in to see her yet. I was told to a few times I'm not sure if I have something, They think the flu shot may have triggered her so hopefully I don't do the same. they haven't given water, I think it's from the fact that unless they give a lot they acidify the blood by production of carbonic acid.

[science_man_88]

I think I found something interesting to talk about with the lucaslehmer() axn came up with. Mind if I see what you think ?

[CRGreathouse]

Go for it.

[science_man_88]

Originally Posted by CRGreathouse

Go for it.

if you replace 0 with s and do:

for(x=1,100,print(lucaslehmer2(x)%x","x))

you get many answers printed but:

for(x=1,100,print(lucaslehmer2(x)%11","x))

gets you only 2 results as far as I see.

[science_man_88]

never mind I see a pattern forming but I bet it's well known.

[kar_bon]

Here are some string maipulation functions, because I missed them much:

- String to upper case
- String to lower case
- Left string
- Right string
- Mid string

Functions like Find or Replace are therefore possible, too.

More suggestions:
- StrFlip: lower to upper and upper to lower in one string
- StrCap: only first character of string/word capitalize
- StrTrim: delete spaces from beginning/end of string

I think StrReverse or CheckPalindrome were done, right?

addhelp(StrToUp, "StrToUp(str): Convert a string str in upper case.");
StrToUp(str)={
  my(sup=Vecsmall(str),s="");
  for(n=1,#sup,
    if(sup[n]>=97 && sup[n]<=122,
	s=concat(s,Strchr(sup[n]=sup[n]-32)),
	s=concat(s,Strchr(sup[n])))
  );
s
};

addhelp(StrToLow, "StrToLow(str): Convert a string str in lower case.");
StrToLow(str)={
  my(sup=Vecsmall(str),s="");
  for(n=1,#sup,
    if(sup[n]>=65 && sup[n]<=90,
	s=concat(s,Strchr(sup[n]=sup[n]+32)),
	s=concat(s,Strchr(sup[n])))
  );
s
};

addhelp(StrLeft, "StrLeft(str,n): Gives back n characters from left of string str.");
StrLeft(str,n)={
  my(strh=Vecsmall(str),s="");
  if(n<1, return(s));		\\ n too small: return empty string
  if(n>=#strh, return(str));	\\ n to big: return str
  for(x=1,n,
      s=concat(s,Strchr(strh[x]))
  );
s
};

addhelp(StrRight, "StrRight(str,n): Gives back n characters from right of string str.");
StrRight(str,n)={
  my(strh=Vecsmall(str),s="");
  if(n<1, return(s));		\\ n too small: return empty
  if(n>#strh, return(str));	\\ n too big: return str
  for(x=#strh-n+1,#strh,
      s=concat(s,Strchr(strh[x]))
  );
s
};

addhelp(StrMid, "StrMid(str,n,m): Gives back m characters from position n of string str.");
StrMid(str,n,m)={
  my(strh=Vecsmall(str),s="");
  if(n<1, n=1);			\\ n too small: set n=start of string
  if(n>#strh, return(s));	\\ n too big: return empty string
  if(n+m>#strh, m=#strh-n+1);	\\ m too big: set m maximum length available
  for(x=n,n+m-1,
      s=concat(s,Strchr(strh[x]))
  );
s
};

Notes:

- The expression "sup[n]=sup[n]+32" won't work with "sup[n]+=32" !

- Typing in characters like German Umlaute are not allowed/not doable in PARI!

[science_man_88]

Originally Posted by kar_bon

I think StrReverse or CheckPalindrome were done, right?

So is FaR lol

[CRGreathouse]

Originally Posted by kar_bon

- The expression "sup[n]=sup[n]+32" won't work with "sup[n]+=32" !

It should...

> v=vector(3,n,n);v[2]+=10;v
%1 = [1, 12, 3]
> v=vectorsmall(3,n,n);v[2]+=10;v
%2 = Vecsmall([1, 12, 3])

Originally Posted by kar_bon

- Typing in characters like German Umlaute are not allowed/not doable in PARI!

Right, it uses C strings rather than Unicode. A person who cared should be able to hack together a solution with enough care, but since I avoid Pari for string processing I haven't though about it much. (I have run into it, though, like when I mention French or German authors in addhelp() lines and can't use accents in their names.)