The exact question would be "is the equation you want to use x=f(Xo)". This is in an if statement already so if true then continue if not then prompt user to enter a different function.
Your bit about its already being inside an if statement isn't very workable because that doesn't allow for an alternative value to be assigned to something in the case that the initial response is negative.
You should be able to work with something like this. Call p(), and assign its result to a ans, say, and then work with that value (and/or test it for some properties).
restart:
p := proc()
local answer, oldprompt, res1, res2;
oldprompt := interface(':-prompt'=``);
try
printf("Is the equation you want to use x=f(Xo)? (y/n)\n");
res1 := readline(-1);
if member(res1,{"y;","y","yes;","yes"}) then
answer := x=f(Xo);
elif member(res1,{"n;","n","no;","no"}) then
printf("Enter your equation.\n");
res2 := readline(-1);
answer := parse(res2);
else
printf("Response not recognized\n");
end if;
catch:
finally
interface(':-prompt'=oldprompt);
end try;
if answer='answer' then NULL else answer end if;
end proc:
ans := p();
[edited below]
It is possible to get it a little closer to your original. With procedure p as below the returned result will be one of true/false/FAIL and could be used in a conditional. In the case that the return values if false (because of the response to the initial query) then a second query is made about the choice of another expression.
This version of p takes two arguments, the first is the suggested initial equation. The second is a name which can be assigned any alternative.
restart:
p := proc(candidate, resultvar)
local result, oldprompt, res1, res2;
oldprompt := interface(':-prompt'=``);
try
printf(sprintf("Is the equation you want to use %a? (y/n)\n",
candidate));
res1 := readline(-1);
if member(res1,{"y;","y","yes;","yes"}) then
result := true;
assign(resultvar,candidate);
elif member(res1,{"n;","n","no;","no"}) then
result := false;
printf("Enter your equation.\n");
res2 := readline(-1);
assign(resultvar,parse(res2));
else
printf("Response not recognized\n");
result := FAIL;
end if;
catch:
finally
interface(':-prompt'=oldprompt);
end try;
return result;
end proc:
Now we can test it out.
p(x=f(X0), 'ans');
ans;
We could also use the call to p inside an if statement. Eg,
if p(x=f(X0), 'ans') then
"accepted";
else
"new choice made";
end if;
ans;
Here, answering "n" to the first query will make the conditional test see a false value, but the named argument ans will get assigned to as a side-effect.
Related
ERROR at line 8: PL/SQL: Statement ignored
CREATE OR REPLACE PROCEDURE POS(A IN NUMBER,M IN NUMBER,TOTAL OUT NUMBER)
AS
BEGIN
TOTAL:=0;
WHILE A>0 LOOP
M:=MOD(A,10);
TOTAL:=TOTAL+M;
A:=(A/10);//statement ignored error
END LOOP;
DBMS_OUTPUT.PUT_LINE(TOTAL);
END;
DECLARE
X NUMBER;
Y NUMBER:=5;
Z NUMBER;
BEGIN
POA(X,Y,Z);
END;
OK, I've had a look at your procedure and tried to resolve the issues you are having with it.
You haven't explained much (or indeed anything) about what you are trying to achieve which makes it really difficult to get you an answer.
People on here really want to help but you have to at least give us the tools with witch to provide that help.
Anyhow, with a host of assumptions, here is my version of your procedure with the following assumptions:
Your procedure is names POS (you name it POS in the procedure definition but then try to execute it as POA).
Your main issue was trying to assign a new value to input parameter "a" within the loop. As it is an input parameter it is immutable and you cannot assign new values to it. I have got round this by declaring a local variable "v_iter" and assigning that the value of "a" and then using it to control the loop.
I have added an "exception" section to handle any unexpected errors and output that error via DBMS_OUTPUT. You might want to make this more robust.
You do not test to check if the input parameter "a" is null or a valid number (i.e. not negative), you might want to do this to make your procedure more robust.
Here is the changed code:
CREATE OR REPLACE
PROCEDURE POS (
a IN NUMBER,
m IN NUMBER,
total OUT NUMBER
)
AS
— Declare variables
v_iter NUMBER := a;
BEGIN
— Initialise total
total := 0;
— Loop through “v_iter”
WHILE v_iter > 0
LOOP
m := MOD(v_iter,10);
total := total + m;
v_iter := (v_iter/10);
END LOOP;
DBMS_OUTPUT.put_line(total);
EXCEPTION
WHEN others
THEN
— Output and raise an error;
DBMS_OUTPUT.put_line(sqlerrm);
RAISE;
END POS;
/
To call it:
DECLARE
X NUMBER;
Y NUMBER:=5;
Z NUMBER;
BEGIN
POS(X,Y,Z);
END;
/
Hope it helps.
I keep receiving error,';' unexpected in this piece of maple code. I have looked and looked and just can't seem to find where I'm going wrong. Can anyone spot it?
QSFactorization := proc (n::(And(posint, odd)), mult::nonnegint := 0, { mindeps::posint := 5, c := 1.5 })
local mfb, m, x, fb, nfb, r, M, d;
if isprime(n) then
return "(n)"
elif issqr(n) then
return "(isqrt(n))"*"(isqrt(n))"
elif n < 1000000 then
return ifactor(n)
end if;
if mult = 0 then
mfb := MultSelect(n, ':-c' = c)
else mfb := [mult, FactorBase(mult*n, c)]
end if;
m := mfb[1];
if 1 < m then
print('Using*multiplier; -1');
print(m)
end if;
x := m*n*print('Using*smoothness*bound; -1');
print(ceil(evalf(c*sqrt(exp(sqrt(ln(n)*ln(ln(n))))))));
fb := Array(mfb[2], datatype = integer[4]);
nfb := ArrayNumElems(fb);
print('Size*of*factor*base; -1');
print(nfb);
r := Relations(x, fb, ':-mindeps' = mindeps);
M := r[3]; print('Smooth*values*found; -1');
print(nfb+mindeps);
print('Solving*a*matrix*of*size; -1');
print(LinearAlgebra:-Dimension(M));
d := Dependencies(M);
print('Number*of*linear*dependencies*found; -1');
print(nops(d));
print('Factors; -1');
FindFactors(n, r, d)
end proc
I'd really appreciate any insight.
You basic problem is that you are using the wrong quotes inside your print statements. This is invalid,
print('Using*multiplier; -1');
You are using single right-quotes (tick), which in Maple is used for unevaluation. In this case the semicolons inside your print statements are syntax errors.
Use either double-quotes or single left-quotes instead. The former delimits a string, and the latter delimits a name. Eg,
print("Using*multiplier; -1");
print(`Using*multiplier; -1`);
If you choose to go with name-quotes then the print command will prettyprint the output in the Maple GUI with the name in an italic font by default, but you won't see the quotes in the output.
If you choose to go with string-quotes then the print command will show the quotes in the output, but will use an upright roman font by default.
Some other comments/answers (since deleted) on your post suggest that you are missing statement terminators (colon or semicolon) for these two statements,
print(m)
FindFactors(n, r, d)
That is not true. Those statements appear right before end if and end proc respectively, and as such statement terminators are optional for them. Personally I dislike coding Maple with such optional terminator instances left out, as it can lead to confusion when you add intermediate lines or pass the code to someone else, etc.
I have a list of numbers and I want to add them and then multiply them by a constant.
addList := proc(a::list,b::integer)::integer;
local x,i,s;
description "add a list of numbers and multiply by a constant";
x:=b;
s:=0;
for i in a do
s:=s+a[i];
end do;
s:=s*x;
end proc;
sumList := addList([2, 2, 3], 2) works fine but at the same time sumList := addList([20, 20, 30], 2) gives an error.
Can somebody point out the error ?
In the for loop you do s:=s+a[i] but i is set to one of the values in a already - not the index of a value. A first pass fix would be to just change the statement above to s:=s+i.
You could also write the function as
proc(a::list,b::integer)::integer;
convert(a,`+`)*b;
end;
Even shorter, there is
addList:= (a,b)-> `+`(a[])*b;
I am pulling data from table Supervisors. Through each iteration, I want to know when Supervisor.SupNum changes. If the value changes, do this. If it stays the same, do the other.
How would I accomplish this?
try this.
if (Supervisor.SupNum = chk) then
flag =true; else
chk := Supervisor.SupNum; flag =false end if;
If you want the first iteration to be true then have another iterator i.
if (i=0) then Supervisor.SupNum := chk; end if; i++;
I am encountering a problem when manipulating sequence element in Maple. First of all, here is the code.
b[0] := t -> (1-t)^3;
b[1] := t -> 3*t*(1-t)^2;
b[2] := t -> 3*t^2*(1-t);
b[3] := t -> t^3;
P := seq([seq([j*(i+1), j*(i-1)], i = 1 .. 4)], j = 1 .. 3);
EvalGamma := proc (b, P, i, t)
local CP, res;
option trace;
CP := P[i];
res := CP[1]*b[0](t)+CP[2]*b[1](t)+CP[3]*b[2](t)+CP[4]*b[3](t);
RETURN res;
end proc;
The variable P is a sequence of sequence : P[i] is a sequence of four 2D points.
But the affectation CP := P[i]; doesn't do what I want : I don't know why but the result is not P[i] in the procedure.
And the weird thing is that, outside the procedure, the following lines work :
CP := P[1];
CP[1];
I would appreciate any suggestions. Thanks.
I'm assuming you call the procedure as
EvalGamma(b,P,i,t)
The problem you are having is that when P is inserted into the sequence of arguments, the nested sequence of arguments is "flattened" to produce the final argument list. An easy way to fix this is to place the sequence for P inside a list structure. So use
P := [seq([seq([j*(i+1), j*(i-1)], i = 1 .. 4)], j = 1 .. 3)];
Once you do that, I think everything will work as expected.
When you call EvalGamma you cannot pass that global P which is an expression sequence of (three) lists (or lists). If you try and do so then EvalGamma will receive 6 arguments instead of 4 as you intend, because each of the three lists (of lists) in expression sequence P gets interpreted as a separate argument of the call.
Instead, you could create P as a list, ie,
P := [seq([seq([j*(i+1), j*(i-1)], i = 1 .. 4)], j = 1 .. 3)];
or you could pass it like EavlGamma(b, [P], some_i, some_name). But you should only do one of those two choices.
Note that the return syntax should be either return res; or (deprecated) RETURN(res);.