Preben Alsholm

MaplePrimes Activity


These are replies submitted by Preben Alsholm

@dharr I guess that kencom1 uses inf as a substitute for infinity.
For inf:=3
odeplot(S1,[y,u[1](y)],0..inf); 
gives us:

and for inf:=10 we get:

Thus kencom1 has more work to do.

@Carl Love That is very nice!

@C_R acer simply defined N as op. Try this:
 

restart;
`print/op`:=()->Typesetting:-Typeset(args):


mass := %op(1) * Unit(m);
value(mass);


mass2 := %op(1) * Unit(cm);
mass + mass2;
simplify(value(%));

Any procedure p becomes inert if preceded by %:
Simple example:
 

p:=proc(x) x*sin(x) end proc;
p(t);
%p(t);
value(%);

See the help page ?%inert, where it says:

You can also make any Maple function inert by prefixing it with the % symbol.

By 'function' is meant a procedure like sin, whereas sin(x) is not. sin(x) is, however, of type function in Maple. Confusing, yes, but it has been the lingo in Maple forever.

@C_R In 1D (aka Maple notation), but NOT in 2D, you can use:
 

f:= k -> local i; add({seq(ifelse(floor(k/i)=k/i,i,0),i=1..k-1)});
f(945);

This works in recent releases, e.g. also in Maple 2021.
In Maple 12 I just tried ? `if`. Up came the help page The Selection (Conditional) Statement and Operator.
About the if operator it says:

if operator
     `if`(conditional expression, true expression, false expression)

@C_R You could do like this to make your version perfectly clear:
 

restart;
g:= k -> {seq(ifelse(floor(k/i)=k/i,i,NULL),i=1..k-1)};

g(945);
add(g(945));

 ifelse doesn't exist in Maple 13, but `if` certainly does.
Here is a version that works in Maple 12 and therefore surely in Maple 13:

restart;
g:= k ->seq(`if`(floor(k/i)=k/i,i,NULL),i=1..k-1);

g(945);
`+`(g(945));  #not using add


 

@dharr Thanks to you for pointing to the right place.
Now I'm logged in.

@sursumCorda My guess is the opposite: With _EnvLinalg95:=true some use may be made of the old linalg package in computing output from some LinearAlgebra commands.

How did you come to know about the existence of _EnvLinalg95?
I never heard of it before.

Could _EnvLinalg95 have something to do with the old linalg package? The number 95 could refer to the year 1995.
So setting _EnvLinalg95:=true could mean that you now work in an environment where use is made of that old and deprecated package.
If you try with(linalg);  you get the contents. There doesn't seem to be any command like EigenConditionNumbers, thus the LinearAlgebra version is used.

@ I tried method=Parts on both examples in Maple 2023.2 as mentioned by Igor Proskurin.
Specifically:
 

res:=int(integrand,t,method=Parts):
res2:=int(integrand2,t,method=Parts):
simplify(integrand-diff(res,t)); # 0
simplify(integrand2-diff(res2,t)); # 0

 

@Preben Alsholm The seven points remained as I feared.
Any reference to the question seems to be gone, which is a good.
 

@C_R I thought of that, but I was afraid that the undeserved points would remain.
It is worth trying though. If the points remain then that exposes a flaw in MaplePrimes.
I can live with 7 undeserved points.

As seen (until tomorrow)  in my answer to my own test question "How to determine if 2+2 = 4?" I'm able to select my own answer as the best answer. It ought not be possible in my view! I received 7 points. Nobody is able to give himself 5 points by giving the answer a vote up. Why should it be different for selecting the best answer?
I shall remove my question and my 7 points tommow morning (Sunday).

@Carl Love Thanks, I shall remove the whole thing, including the points, tomorrow morning.

@Preben Alsholm I prefer that it is removed!
(And the 7 points I received are deducted as well!)

I shall do a test question and quickly answer it myself to see what happens.

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