## 4423 Reputation

8 years, 314 days

## maybe?...

I don't know, but I wonder if windspeed data could be pulled from https://earth.nullschool.net

## Nice!...

Two thumbs up for the clustering and geographic additions!  This new edition looks like it will be a joy to explore.  I've been lost for innovative ideas in Maple the last couple of years, I hope to apply some ideas in the new Maple and to compile some things to apply and to improve on.

@Bryon thank you

## can administrators repair the mistake?...

It seemed like an interesting enough question - homework regardless - it does appear the question was mistakenly identified as spam.

## Geometry expressions or Maple...

As a relatively avid maple user, some time ago I required the use of Geometry expressions, to find an equation based on various angles and lengths with respect to something else.  I could have done it by hand, but of course it was easier to draw the pictures in Geometry expressions.  This could not be done so easily with Maple I recall.

## screenshot?...

Can you present a screenshot?  Also provide Maple version and OS.  Probably just a restart will suffice.

It is something that is impossible to occur.

## 2016.1 bug...

@ Kitonum - It does not work in Maple 12.

Error, (in pdsolve/sys) unable to handle PDE problem subject to boundary conditions {u(0, y) = 0, (D[1](u))(0, y) = 0}

However it does work in Maple 18.  Therefore this is a regression bug that exists in 2016.1  No one has been able to confirm if it exists in 2016.0 or not.  I will be able to confirm this tomorrow.

## no difference...

So what we've concluded is 2016.1 won't solve the it using pdsolve but will using dsolve.  And 2016.2 understands it as such and calculates it as it should.  Am I correct?

I wonder if anyone else could verify this 2016.1 issue.  Does it exist in 2016.0?

## strange...

Strange, I also have Maple return nothing after the pdsolve.

if I switch conditions (0,y) to (x,0) we get an answer, not sure why (0,y) shouldn't also give one.

```eq := diff(u(x, y), x, x)-y*(1+x) = 0; pdsolve({eq, u(x, 0) = 0, (D[1](u))(x, 0) = 0});
/ d  / d         \\
|--- |--- u(x, y)|| - y (1 + x) = 0
\ dx \ dx        //
1    3   1    2
u(x, y) = - y x  + - y x  + _F1(y) x + _F2(y)
6        2
```

I am also using Windows 7 Maple 2016.1  64 bit.

## mw file outside of maple...

I think yes the op means from .mw file and the contents of the file.  I'm guessing he wants to edit or view his worksheet from a computer that does not have maple installed, probably from work or something.

Opening the mw file in notepad or word will produce not much useful information for viewing let alone editing, lots of gobbledygook.  There are a couple of options.   One option is to use mapleprimes.  I'm guessing you have access to the file.  You could start to edit a question on mapleprimes and upload the contents of the file for viewing but don't actually submit the question.  This way you can view the contents of the file as if you were viewing it from maple.

The other option is to use the free Maple player (of course if you're trying to view from work, you would have to install first which I'm guessing is restricted or offlimits).

## Which one is correct? Different values...

```restart; Digits := 15; to 12 do evalf(add(sin(k), k = 1 .. 10000)); gc() end do;
12 times 1.63389102179226```

On my system Maple 2016.1

```restart; Digits := 15; to 12 do evalf(add(sin(k), k = 1 .. 10000)); gc() end do;
12 times  1.63389102179247
```

Changing the location of gc() we get yet another different result.

```restart; Digits := 15; to 12 do gc(): evalf(add(sin(k), k = 1 .. 10000)) end do;
12 times  1.63389102179238
```

forcing a scalar decimal, we get yet still a different value

```restart; Digits := 15; to 12 do gc(); evalf(add(sin(k*1.), k = 1 .. 10000)) end do;
12 times  1.63389102179250```

So we've calculated the same thing 3 different ways with 3 different results.

Yet again by accident doing two garbage collections we get varying values

```restart; Digits := 15; to 12 do gc(); evalf(add(sin(k), k = 1 .. 10000)); gc() end do;
15
1.63389102179231
1.63389102179259
1.63389102179252
1.63389102179246
1.63389102179250
1.63389102179240
1.63389102179237
1.63389102179241
1.63389102179236
1.63389102179255
1.63389102179220
1.63389102179240
```

I guess in this case two garbage collections cancel each other out.

## gc() dicouraged as of Maple 16...

I recall mention of garbage collection not required in newer versions of maple.  In the help gc() is discouraged to be used as of Maple 16.

## garbage collection...

However executing this statement gives different results every once in a while

evalf(add(sin(k), k = 1 .. 10000)); gc()
1.633890952

```restart; Digits := 10; to 12 do evalf(add(sin(k), k = 1 .. 10000)); gc() end do;
1.633891011
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
1.633891012
```

interface(version);
Standard Worksheet Interface, Maple 2016.1, Windows 7, April 22

2016 Build ID 1133417

## last 3 digits...

It seems to be only the last 3 digits that change.  In the Standard interface it changes once in a while, but when I run a loop, the numbers are all the same except that is pauses as it displays the 10 they are all the same.  It's only when I execute it singly do I get changes, but they only happen on the last three digits no matter how many digits I choose, it's always only the last 3..

evalf(add(sin(k), k = 1 .. 10000), 25);
1.633891021792462265108436

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