awehring

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9 years, 357 days

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These are replies submitted by awehring

Yesss ! Thats it! Works like a charm. :-)

Thank you.

Yesss ! Thats it! Works like a charm. :-)

Thank you.

Thank you, acer. I guess I learned something about map. :-)

But with this one I only found a complicate solution:

 

U = x+(R-y)^(1-Theta)/(1-Theta)

lhs((%)) = op(1, op(2, (%)))+ln(-numer(op(2, op(2, (%)))))/(-denom(op(2, op(2, (%))))) assuming R > y

`assuming`([lhs(U = x+(R-y)^(1-Theta)/(1-Theta)) = op(1, op(2, U = x+(R-y)^(1-Theta)/(1-Theta)))+ln(-numer(op(2, op(2, U = x+(R-y)^(1-Theta)/(1-Theta)))))/(-denom(op(2, op(2, U = x+(R-y)^(1-Theta)/(1-Theta)))))], [R > y])

simplify((%), ln) assuming (R-y) > 0, Theta > 0

U = x+ln(R-y)

So, the result is nice, but my first transormation is quite complicated. In addition, I have to put a - at the numerator and the denominator, that it works. Because Maple changes the sign ahead of the fraction, for whatever reason.

I guess, there is an easier way.

 

 

Thank you, acer. I guess I learned something about map. :-)

But with this one I only found a complicate solution:

 

U = x+(R-y)^(1-Theta)/(1-Theta)

lhs((%)) = op(1, op(2, (%)))+ln(-numer(op(2, op(2, (%)))))/(-denom(op(2, op(2, (%))))) assuming R > y

`assuming`([lhs(U = x+(R-y)^(1-Theta)/(1-Theta)) = op(1, op(2, U = x+(R-y)^(1-Theta)/(1-Theta)))+ln(-numer(op(2, op(2, U = x+(R-y)^(1-Theta)/(1-Theta)))))/(-denom(op(2, op(2, U = x+(R-y)^(1-Theta)/(1-Theta)))))], [R > y])

simplify((%), ln) assuming (R-y) > 0, Theta > 0

U = x+ln(R-y)

So, the result is nice, but my first transormation is quite complicated. In addition, I have to put a - at the numerator and the denominator, that it works. Because Maple changes the sign ahead of the fraction, for whatever reason.

I guess, there is an easier way.

 

 

Oh, yes, thanks. The space was missing.

Oh, yes, thanks. The space was missing.

@Preben Alsholm Ohh ! Thanks. I really mixed FAIL and FALSE.

So it behaves as I would expect.

 

 

@Preben Alsholm Ohh ! Thanks. I really mixed FAIL and FALSE.

So it behaves as I would expect.

 

 

To be honest, I'm really disapointed from Maple.

I mean, when I use an algebraic computing system, I expect it to deliver correct and reliable results.

The documentation of testeq says:

"The result FALSE is always correct; the result TRUE may be incorrect with very low probability."

And now - as you said -  it comes out, that FALSE can really mean "false" (= equations are not equal) or it can mean "don't know". It should - at the very least (!) - state "don't know", "too lazy", or whatever, when it cannot give a correct answer.

As it is now, the result from testeq is worthless: FAIL is unreliable, TRUE may be incorrect with a low probability.

 

That this is documented in the help system does not really help. Do I have painstakingly dissect the help system of any command I use, to find out, if and in which special circumstances the command is usable? The descriptions of the commands are often several pages long and not easy to grasp. I would expect, that Maple says it clearly by itself, when it reaches its limits.

In this example testeq is a simple function and my equations are quite simple too. That Maple fails in so simple circumstances makes me very suspicious. I don't know if I really shall relay on it for important calculations. In other words: shall I use Maple any more?

 

To be honest, I'm really disapointed from Maple.

I mean, when I use an algebraic computing system, I expect it to deliver correct and reliable results.

The documentation of testeq says:

"The result FALSE is always correct; the result TRUE may be incorrect with very low probability."

And now - as you said -  it comes out, that FALSE can really mean "false" (= equations are not equal) or it can mean "don't know". It should - at the very least (!) - state "don't know", "too lazy", or whatever, when it cannot give a correct answer.

As it is now, the result from testeq is worthless: FAIL is unreliable, TRUE may be incorrect with a low probability.

 

That this is documented in the help system does not really help. Do I have painstakingly dissect the help system of any command I use, to find out, if and in which special circumstances the command is usable? The descriptions of the commands are often several pages long and not easy to grasp. I would expect, that Maple says it clearly by itself, when it reaches its limits.

In this example testeq is a simple function and my equations are quite simple too. That Maple fails in so simple circumstances makes me very suspicious. I don't know if I really shall relay on it for important calculations. In other words: shall I use Maple any more?

 

@Preben Alsholm: Thank you for the explanation.

That means, everytime testeq FAILs, I have to check with debug, to be shure?

 

@Adri van der Meer: Thanks !

Is "is" reliabel in any case?

 

@Preben Alsholm: Thank you for the explanation.

That means, everytime testeq FAILs, I have to check with debug, to be shure?

 

@Adri van der Meer: Thanks !

Is "is" reliabel in any case?

 

In my problem above is a small typo in equation (3): it contains pi1 instead of p1.

Don't be confused by this.

This is just a cut and paste error here, because originally I had defined alias(pi1 = p1) with pi1 as an Atomic Identifier. I removed this to simplify the problem and it did not change the wrong behavier of testeq.

The attatched worksheet is ok (e.g. shows the bug).

Thank you too !

I didn't know the map command. It appears quite usefull for "formating".

Do you have hints, how to learn these functions (as discussed above with Markiyan Hirnyk).

 

Thank you too !

I didn't know the map command. It appears quite usefull for "formating".

Do you have hints, how to learn these functions (as discussed above with Markiyan Hirnyk).

 

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