Hi,

This more a warning to focus your attention on a specific point than a true question.
 

I submit you this test case which works in Maple 2015 and Maple 2016 but not in Maple 2018.

In a few words:

• let X and Y two independant random variables with respective distributions Normal(mu__x, sigma__x) and  
  Normal(mu__y, sigma__y)
   
• let Z := q -> cos(q)
   
• You can easily verify that Maple can compute the formal expression of Mean(Z(X)) and Variance(Z(X))
  (which means that it could compute Z(X+Y) for X+Y is just another gaussian RV)
   
• What I found is that:
  1. Mean(Z(X+Y)) returns same expressions in Maple 2015 and Maple 2016, but a different one in Maple 2018.
     Luckily the later is more readable than the former ones, and closer to the one of Mean(Z(U))  where U=X+Y is the RV of distribution Normal(mu__x+mu__y, sqrt(sigma__x^2+sigma__y^2))
     This suggest that the integration algorithm has evolved somewhere in between Maple 2016 and Maple 2018
      
  2. While Maple 2015 and Maple 2016 return an evaluated result for Variance(Z(X+Y)) Maple 2018 fails.
      

Can this "failure" be fixed by some adhoc option of Variance?
Or could it come from a "regression" in the implementation of this procedure (or of the underlying int procedure) in Maple 2018?

PS: I did not try to compute Variance(Z(X+Y)) from an explicit double integration

Stat_2015.mw

Hi 

I am having problems with the syntax/symbols i maple. I down know what "setting" has changed but + and - and so on, has change to K and C. anyone know how to fix this?

Regards

Morten

Hi everyone,

Was hoping someone could point me in the right direction. A homework question asks us to create a function using arrow (->) notation which take a Maple list of complex numbers as its input and returns the largest modulus from that list.

I've tried writing this without arrow notation --

Say L1 is a list of complex numbers:

max(abs~(L1))

and this seems to work fine. But I'm particularly struggling with how to introduce the arrow notation into this.

Any help would be much appreciated!

When I solve in worksheet mode the limit of (2*abs(x-2)+abs(x+1)-3)/(abs(x^2-4)+x-2) evaluating the limit in x=2- the result is 1/3 and in x=2+ the result is 3/5, but if I try to use the Tutorial/Single Variable/Limits, an error occurs.

Any Suggestion?

how I can find an non-trial solution (non-zero) for differential equations?

Thanks

y.mw
 

Download y.mw

I wish to process a string of letters into a list of one or more characters which are comma separated at each change of character. The following function will achieve this, but its output is not as list [ ] in the format required.  

Below is a routine to split a character string based on change of character: (ref: https://rosettacode.org/wiki/Split_a_character_string_based_on_change_of_character#Maple)

splitChange := proc (str::string) local start, i, len; start := 1; len := StringTools:-Length(str); for i from 2 to len do if str[i] <> str[start] then printf("%s, ", str[start .. i-1]); start := i end if end do; printf("%s", str[start .. len]) end proc;
splitChange("WPKCPYWYYYXHYY");# 

Here is the output:
W, P, K, C, P, Y, W, YYY, X, H, YY

This print-to screen output is not usable, instead I need the output in list format i.e. ListY:= ["W", "P", "K", "C", "P", "Y", "W", "YYY", "X", "H", "YY"].

Background

 In my model, each of these character strings is a node of a graph, and their adjacencies represent an edges of a graph.  I aim to automatically map strings into a set of directed adjacencies as output; for example:  

AdjSet:= {[W, P], [P, K], [K, C], [C, P], [P, Y], [Y, W], [W,YYY],[YYY, X], [X, H], [H,YY]}.

This set will be the input to a directed graph, e.g: 
M := Digraph(AdjSet); DrawGraph(M);
from which our objective, the adjacency matrix of the nodes can be obtained in MAPLE.  

Help

Can someone please help me by modifying the SplitChange rountine so that it produces output in the form of ListY above? 

Thanks in anticipation of your help

Melvin Brown
 

Hi,

In a recent post acer made me discover the joy of Typesetting to customize the outputs (acer, if you read this question: big thanks to you, really funny and powerful!)

I'm interested in using Typesetting for output coloring (for instance) but I would like that these outputs to be left justified.
Up to now I used to use printf to manage the outputs the way I wanted, but I failed combining Typesetting and printf.

Is it possible to exploit the capabilities of Typesetting in printf commands?
Or, at least, is it possible to "left-justify" print outputs programatically?

Thanks for your answers

I have assumed lambda <-1 yet signum(lambda) returns lambda~.  It should be -1. I need to show that the expression lambda is used in is negative. 

Download signum_problem.mw

Hi,

When you do this a := plot(1/x, x=0..1);  the figure contains a "smart" graph which extends roughly from 0 to 30 in the vertical direction.
(no discont=true nor smartview=false used here, numpoints set to its default falue)

If you use plottools:-getdata(a); you find that the vertical range is about  0..1800.
It seems to mean that smartview=true (the default setting) overrides the range determined from the values of discont and numpoints?
 

My question is: Is it possible to retrieve the vertical range that plot uses when it displays the graph?
 

Hello Dr/Pof/Colleague

Please help me on the ODE BVP problem

my target i want RUN double loop

Download 3DAKc2alpha.mw

I am developping an algorythm in which I need to obtain a 3D plot and its respective colorbars. As far as I know, Maple does not have a function with includes such a colorbar automatically (like Matlab, for example). So, I have had to get 3D plot and colorbar separatelly, as independent plots. It has worked fine, but now I need to export such graphics as EPS files, which imply merging them as a single graphic.

Here is a small example, where I try to put such graphics inside a table for then exporting it as EPS:

restart:

with(plots):
with(DocumentTools):

graph:= plot3d(x^2+y^2, x = -10..10, y = -10..10, colorscheme = ["zgradient", ["Red","Blue"]]):

grad_min, grad_max:= (min, max)(op([1,3], indets(graph, specfunc(anything, GRID)))):

colorbar:= densityplot(axis_z, axis_x = 0..0.1, axis_z = grad_max..grad_min, style = patchnogrid, size = [100,250], axes = boxed, tickmarks = [0,10], labels = ["",""], colorscheme = ["zgradient", ["Red","Blue"]]):

tab:= Tabulate([graph, colorbar], exterior = none, interior = none, weights = [4,1]):

 It has not worked, though. Can anyone suggest a solution for that? I need to export both graphics as one single file, preferably EPS, because of its high resolution.

Let us consider

plots:-inequal(max(1, min(x, 2))+max(1, min(y, 2)) <= 3, x = -4 .. 4, y = -4 .. 4);

and compare it with

plots:-implicitplot(max(1, min(x, 2))+max(1, min(y, 2)) = 3, x = -4 .. 4, y = -4 .. 4, gridrefine = 2);

The latter plot must be a subset of the former plot, but it isn't so. bug_in_inequal.mw

Hi guys! First time posting here and I'm very new to Maple too.

I'm using maple right now to calculate statics problems, and for that we've customized some units to better fit what we're working with and want to see in output. In general, it's working great, but sometimes when I try to use the solve function including these units, I get an error mesage I don't really understand..

Here's the unit customization:

So I was hoping someone could help me fix the error(s), or at least understand what the errors mean..

I have the following Maple code.

x := [5, 10, 15, 20];

y := [4.22, 7.49, 12.24, 19.60];  

yui := [2.48, 3.76, 6.11, 14.60];

yli := [2.27, 3.34, 6.09, 10.90];

with(Statistics): with(plots):

p1 := ErrorPlot(y, coords = x, yerrors = yui);

this produces a plot with error bars. The problem is that I acutally have unequal errors. In the ErrorPlot helpfile it says:

"This options specifies errors along the x-axis. The array of errors must have the same number of elements. To specify right errors and left errors separately, use the list of two vectors." (this pertains to xerrors obviously but below it says the same applies to yerrors)

I have tried entering the code above with yerrors=[yli,yui] and with yerrors={yli,yui}....but neither option works and I get the error:

"Error, invalid input: Statistics:-ErrorPlot expects value for keyword parameter yerrors to be of type {identical(default), [{array, list, rtable, DataFrame, DataSeries}, {array, list, rtable, DataFrame, DataSeries}], {array, list, rtable, DataFrame, DataSeries}}, but received {[2.27, 3.34, 6.09, 10.90], [2.48, 3.76, 6.11, 14.60]}"

Can anyone advise me on what I'm doing wrong - I am very new to Maple.

Jo

I have been trying to solve this equation by obtaining solutions for x and I actually handed in for an assignment what Maple gave me as an output. Then it turns out that Maple was wrong. This is in fact not a solution for the equation. What am I doing wrong here?
Solve_error.mw