## 13613 Reputation

19 years, 229 days

## MaplePrimes Activity

### These are questions asked by Preben Alsholm

MaplePrimes

I'm not being notified anymore about responses to answers or comments to MaplePrimes. I'm assuming that I'm not the only one (?). This has happened before.

## The End of Parameters Marker, \$...

Maple 17

A large procedure I made caused me some problems. I finally found the source of the problem.
There seems to be some interaction between the end of parameters marker, \$, and the elementwise operation ~.

Consider these 3 versions of essentially the same procedure:

restart;
Q1:=proc(Var::list,\$) local n;
n:=nops(Var);
print(Var,n);
proc(var::list)
subs(Var=~[seq(1..n)],var); #Elementwise
end proc;
end proc:
Q1([x,y]); #Doesn't work : "invalid expression"
Q2:=proc(Var::list,\$) local n;
n:=nops(Var);
print(Var,n);
proc(var::list)
subs(zip(`=`,Var,[seq(1..n)]),var); # zip
end proc;
end proc:
Q2([x,y]); #No problem
Q3:=proc(Var::list) local n; #No end of parameters marker \$
n:=nops(Var);
print(Var,n);
proc(var::list)
subs(Var=~[seq(1..n)],var); # Elementwise
end proc;
end proc:
Q3([x,y]); # No problem
lprint(Q3([x,y])); #Curious output involving ` \$`
#A fourth procedure in which the output is not a procedure works:
Q4:=proc(Var::list,\$) local n;
n:=nops(Var);
print(Var,n);
subs(Var=~[seq(1..n)],Var)
end proc:
Q4([x,y]);

Does anybody have any comments? Is it a bug?

## MaplePrimes and the inequality sign <...

Maple

Any plans of correcting the obvious problem the MaplePrimes text editor has with the inequality sign < ?
It is really quite annoying.
Everything on a line of code after < is very often discarded with the obvious effect that the code doesn't run.

Maple

## Plot in procedure...

Maple

I know that I have raised this question before, and also got some responses.

However, I cannot find the thread, and I'm still interested in what is going on.

I don't have a clue.

restart;
f:=proc(a)
plot(sin(x),x=0..Pi);
#plot(x^3,x=0..1);
#plot(undefined,x=0..1);
a^2
end proc:

#Now try plotting what should be the parabola y = x^2 on the interval -1..1: