So I want this to find me the roots of a polynomial. However, everytime I run it, it never gives me any roots, even if I use an obvious one like 2x-2. Why won't it work?
Input "Degree?",θ
Disp "Left to right"
Disp "coefficients"
1→V
For(Z,0,θ)
Input A
Q→R
P→Q
O→P
N→O
M→N
L→M
K→L
J→K
I→J
H→I
G→H
F→G
E→F
D→E
C→D
B→C
A→B
If V=1
Then
A→S
V=0
End
End
For(T,–A,A)
For(U,–W,W)
If T≠0
U/T→X
RX+Q→Y
YX+P→Z
ZX+O→Y
YX+N→Z
ZX+M→Y
YX+L→Z
ZX+K→Y
YX+J→Z
ZX+I→Y
YX+H→Z
ZX+G→Y
YX+F→Z
ZX+E→Y
YX+D→Z
ZX+C→Y
YX+B→Z
If Z=0
Then
Disp X
End
End
End
prgmRESET
RESET just resets the variable values. What is wrong with it?
Request: I have absolutely no idea what operation you are working off of, if you could please state that
Observation: You're using a lot of variables that haven't had any value assigned to them or initially cleared, I can see that you're trying to create a 'stream' of variables to work with, but if you do this without clearing the variables ahead of time then you create problems in your later calculations.
Coding Recommendations:
You state V=0, which does nothing in this context, instead of assigning it a value
You can change 'If T≠0' into just 'If T'
In your third 'For()' statement, "W" is undefined in the code.
You can change 'If Z=0:Then:Disp X:End', near the end of your code, into just 'If not(Z:Disp X'
Move prgmRESET to the top of your program
To be honest, I'm not entirely sure how you code is supposed to find the routes of a polynomial. Your error is most likely occurring somewhere in your mess of variable assigning/reassigning/swapping. I would redo your code using lists instead of basic variables.
If all you want to do is find the routes of a polynomial, I can give you a program for that.
:Prompt L1,X
:Repeat 1=dim(L1
:dim(L1->dim(L3
:seq(L1(A)(Ans-A),A,1,Ans-1->L2
:Repeat abs(Ans)<10^(-7
:L1(1->L3(1
:For(A,2,dim(L1
:XL3(A-1)+L1(A->L3(A
:End
:Ans->B
:L2(1->L3(1
:For(A,2,dim(L2
:XL3(A-1)+L2(A->L3(A
:End
:Ans^-1(AnsX-B->X
:B
:End
:Disp X
:L1(1->L2(1
:For(A,2,dim(L1)-1
:XL2(A-1)+L1(A->L2(A
:End
:L2->L1
:End
I'm not quite sure what you're trying to do here. You use a whole lot of variables without ever clearing or defining them, which probably means that all of your values will be 0.
Also, recommendation for future TI-BASIC questions:
PLEASE explain your variables. There's nothing worse than having a mess of variables and expecting the reader to do detective work to find out what they're supposed to do. Plus, it's helpful for you as well when you decide to come back to it for troubleshooting.
Related
I have created a deck class and have defined one of the functions to insert a card at the beginning of the array. However everytime I try to test it in my test script I receive `add_to_bottom': wrong number of arguments (1 for 0) (ArgumentError). Can someone please help me I know I am close to figuring it out.
Deck Class
def add_to_bottom
#cards.insert(0, c)
end
Test Script
d = Deck.new
c = Card.new(7, "S")
d.add_to_bottom(c)
print d, "\n"
add_to_bottom has c in the method body, which is neither a method nor a variable. If that is meant to be an argument passed, then you need to write def add_to_bottom(c). If you do that, then that would also resolve your error.
Your add_to_bottom expect no arguments while in the test code you provide an argument. Did you forget to declare it in your function declaration?
I'm not sure how your Deck or Card classes are implemented, so it is hard to say. One very obvious problem is what #sawa and #VuMinhTan have already pointed out. So, as they said, you definitely should be taking in parameter c in the method you defined (add_to_bottom).
It seems evident to me that Card.new(7, "S") is making a 7 of Spades. This is just my curiosity, and nothing "wrong" with your code, but I'm also wondering how one would consider index 0 the "bottom". Of course, it really makes no difference, but that seems to be the "top" to me.
I was looking for a Ruby code quality tool the other day, and I came across the pelusa gem, which looks interesting. One of the things it checks for is the number of else statements used in a given Ruby file.
My question is, why are these bad? I understand that if/else statements often add a great deal of complexity (and I get that the goal is to reduce code complexity) but how can a method that checks two cases be written without an else?
To recap, I have two questions:
1) Is there a reason other than reducing code complexity that else statements could be avoided?
2) Here's a sample method from the app I'm working on that uses an else statement. How would you write this without one? The only option I could think of would be a ternary statement, but there's enough logic in here that I think a ternary statement would actually be more complex and harder to read.
def deliver_email_verification_instructions
if Rails.env.test? || Rails.env.development?
deliver_email_verification_instructions!
else
delay.deliver_email_verification_instructions!
end
end
If you wrote this with a ternary operator, it would be:
def deliver_email_verification_instructions
(Rails.env.test? || Rails.env.development?) ? deliver_email_verification_instructions! : delay.deliver_email_verification_instructions!
end
Is that right? If so, isn't that way harder to read? Doesn't an else statement help break this up? Is there another, better, else-less way to write this that I'm not thinking of?
I guess I'm looking for stylistic considerations here.
Let me begin by saying that there isn't really anything wrong with your code, and generally you should be aware that whatever a code quality tool tells you might be complete nonsense, because it lacks the context to evaluate what you are actually doing.
But back to the code. If there was a class that had exactly one method where the snippet
if Rails.env.test? || Rails.env.development?
# Do stuff
else
# Do other stuff
end
occurred, that would be completely fine (there are always different approaches to a given thing, but you need not worry about that, even if programmers will hate you for not arguing with them about it :D).
Now comes the tricky part. People are lazy as hell, and thusly code snippets like the one above are easy targets for copy/paste coding (this is why people will argue that one should avoid them in the first place, because if you expand a class later you are more likely to just copy and paste stuff than to actually refactor it).
Let's look at your code snippet as an example. I'm basically proposing the same thing as #Mik_Die, however his example is equally prone to be copy/pasted as yours. Therefore, would should be done (IMO) is this:
class Foo
def initialize
#target = (Rails.env.test? || Rails.env.development?) ? self : delay
end
def deliver_email_verification_instructions
#target.deliver_email_verification_instructions!
end
end
This might not be applicable to your app as is, but I hope you get the idea, which is: Don't repeat yourself. Ever. Every time you repeat yourself, not only are you making your code less maintainable, but as a result also more prone to errors in the future, because one or even 99/100 occurrences of whatever you've copied and pasted might be changed, but the one remaining occurrence is what causes the #disasterOfEpicProportions in the end :)
Another point that I've forgotten was brought up by #RayToal (thanks :), which is that if/else constructs are often used in combination with boolean input parameters, resulting in constructs such as this one (actual code from a project I have to maintain):
class String
def uc(only_first=false)
if only_first
capitalize
else
upcase
end
end
end
Let us ignore the obvious method naming and monkey patching issues here, and focus on the if/else construct, which is used to give the uc method two different behaviors depending on the parameter only_first. Such code is a violation of the Single Responsibility Principle, because your method is doing more than one thing, which is why you should've written two methods in the first place.
def deliver_email_verification_instructions
subj = (Rails.env.test? || Rails.env.development?) ? self : delay
subj.deliver_email_verification_instructions!
end
It has been a while since I've used Mathematica, and I looked all throughout the help menu. I think one problem I'm having is that I do not know what exactly to look up. I have a block of code, with things like appending lists and doing basic math, that I want to define as a single variable.
My goal is to loop through a sequence and when needed I wanted to call a block of code that I will be using several times throughout the loop. I am guessing I should just put it all in a loop anyway, but I would like to be able to define it all as one function.
It seems like this should be an easy and straightforward procedure. Am I missing something simple?
This is the basic format for a function definition in Mathematica.
myFunc[par1_,par2_]:=Module[{localVar1,localVar2},
statement1; statement2; returnStatement ]
Your question is not entirely clear, but I interpret that you want something like this:
facRand[] :=
({b, x} = Last#FactorInteger[RandomInteger[1*^12]]; Print[b])
Now every time facRand[] is called a new random integer is factored, global variables b and x are assigned, and the value of b is printed. This could also be done with Function:
Clear[facRand]
facRand =
({b, x} = Last#FactorInteger[RandomInteger[1*^12]]; Print[b]) &
This is also called with facRand[]. This form is standard, and allows addressing or passing the symbol facRand without triggering evaluation.
I have been working on a code in prolog for a while now and it is near compiling worthy and all my ideas seem to be solid so it should work when it compiles. It is a program that consults a database file for a list of clauses and then it awaits for a query by the user which it will then pick what information it needs from the sentence and query the database appropriately but there is a block of code that keeps giving me errors complaining that the flowpattern doesn't exist in the standard predicate this may be a silly question but even with all the looking into this I have done i can't find out how to fix this problem if someone could help me out or point me in the right direction that would be greatly appreciated.
Here is the block of code that gives the error:
loop(STR):-
scan(STR,LIST),
filter(LIST,LISroT1),
pars(LIST1,LIST2),
fail.
loop(STR):- STR >< "",readquery(L),loop(L).
readquery(QUERY):-nl,nl,write("Query: "),readln(QUERY).
scan(STR,[TOK|LIST]):-
fronttoken(STR,SYMB,STR1),!,
upper_lower(SYMB,TOK),
scan(STR1,LIST).
the specific line that the compiler complains about is fronttoken(STR,SYMB,STR),!,
any help will be apreaciated thanks!
Since we are looking at an "ex[c]er[p]t" of the code, it's hard to be sure what is going wrong, but the the given evidence points to this: loop/1 is being called before readquery/1 can do its work to populate (bind) the argument STR to loop/1.
Notice that loop/1 calls itself (recursively), and does so in a repeat/fail pattern. But the first time loop/1 runs, there's no indication in the code shown of how argument STR would get populated.
A clearer (more self-contained) code snippet would be like this:
loop :-
readquery(STR),
scan(STR,LIST),
filter(LIST,LISroT1),
pars(LIST1,LIST2),
fail.
loop :- loop.
This makes it clear that predicate loop doesn't actually return any result (and the given code snippet isn't complete enough to make clear what the program as a whole accomplishes). It assumes that the clauses ahead of fail in loop are deterministic, so that in failing, control passes through to the second (recursive) clause of loop/0. If this is not the case, the determinism could be forced by wrapping each call inside once/1.
So I'm learning yet ANOTHER new language cause apparently my company thinks we should support every thing conceivable under the sun. Next week I suspect a memo about FORTRAN, automatonization, and punch cards. But that's neither her nor there. My question is, I'm running a loop (in this particular case a while loop) and have it collecting a string from the user. Name of pet. This while loop continues to repeat until the user breaks it. However on the second time around I start receiving messages from Ruby telling me that the values have already been preassigned. It doesn't really cause issues as the program continues to run, but it doesn't look good.
Is there any way to clear the values so that it all returns to nil except the values I want, or would it be better to just put everything in functions so that there's no chance of regurgitation?
sample:
while moonies > 0
print "Would you like to punch a kitty? y or n"
y = gets()
if y = 'y'
print "Which kitty would you like to punch?"
slap = gets()
if slap == Tom
print "You spent 50 dollars punching a kitten."
....
else
print "Is there something else you'd like to kick or did you want to spend no money today?"
and so on and so on.
The problem is that when it gets back around to y is when the messages start to appear. thanks for the assistance.
Well...
if y = 'y'
is an assignment, not a comparison for equality. y='y' is always true. Should be
if y == "y\n" #note the newline, you got it from "gets"
if slap == Tom
This is a comparison, but Tom is a constant (it starts with a capital). I'm guessing you reassign a value to it, somewhere in your loop. Ruby complains about it. The newline issue will be here again. slap=gets.chomp will get rid of it.