restart, with(plots);
startingTime := 1800;
interval := 10;
P(0) := 5.308;
P(t) = 5.308*M/(5.308 + (M - 5.308)*exp(-kMt));
                                5.308 M           
              P(t) = -----------------------------
                     5.308 + (M - 5.308) exp(-kMt)

diff(P(t), t) = kP(t)*(M - P(t));
                   d                         
                  --- P(t) = kP(t) (M - P(t))
                   dt                        

Explore(plot([P(t), [[0, 5.308], () .. (), [140, 131.7]]], t = 0 .. 0.140, P = 0 .. 140, style = [line, point], gridlines = true), parameters = [[M = M_0 .. M_1], [k = k_0 .. k_1]]);
Error, (in Explore) incorrect first argument [P(t), [[0, 5.308], () .. (), [140, 131.7]]]

I am currently trying to solve the following ODE using numerical methods:

 + [(z+ I*y)²/k₁² -k₂² + ] 

Where the complex value (in this case, , has been written as z+Iy). I believe dsolve has capabilities for solving this as an initial value problem with complex values and thus to solve this as a boundary value problem I aim to use fsolve to find a zero other a function which is the (IVP solution) - (the non-initial boundary). This has worked very well for the case where y=0 however does not work for values of y>0, and it seems the problem is with fsolve. Any advice on how to deal with this problem, perhaps alternatives to fsolve? 

Is there any possibility to modify column width within tables, so that they become equal?

Dear Users! 

I want to evaluate following integral (f[i]'s) for different values of rho as shown. But find some problem and can't find f[3], f[4], f[5] and f[6]. If the integral from direct way is hard to calculate please guide me how I can evaluate it using numerical integration?

restart; HAM := [1, 2, 3, 4, 5, 6]; U := y^6*sin(x); alpha := 1/3;

for i while i <= nops(HAM) do

rho := op(i, HAM);

f[i] := int(int(U/((x^rho-p^rho)^alpha*(y^rho-q^rho)^alpha), q = 0 .. y), p = 0 .. x)

end do

Thanks in advance!

Special request to @acer @Carl Love @Kitonum @Preben Alsholm

Hi, 

I want to simulate a decision rule (let's say a production control strategy to fix the ideas) based on the outcomes of a binomial random variable.

One stage of this simulation involves operations which correspond to the NaiveProc described below. This procedure is a straightforward and rather naive translation in Maple of these operations.
It is given here to help you to understand what is to be done.

This coding being extremely slow, I implemented the required operations differently.
Given the fact that I'm only concerned by binomial samplings with outcomes 0 and 1, I basically replaced these samplings by three operations  U:=... , Got01:=... , Got0:= ... .
Each new implementation is about 200 times faster than the naive one.

My question is: Can we do still better?
For information the same simulation realized with R runs in less than 15s when REP = 10^8 (more than 100 times faster than what I'm capable to do with Maple)

Thanks for your help.


 

Download MakeItFaster.mw

When Maple converts a matrix or a vector to Latex it uses latex array, which  is fine, but what it does is insert an exatra \\ at the end of the last row, just before the \end{array} 

This causes problem for some software which reads the latex file. It causes the software to take this as empty row and inserts a blank row at the end.

Here is a small example

A:=Matrix([[1,2],[3,4]]);
Physics:-Latex(A);

              \left[\begin{array}{cc}1 & 2 \\3 & 4 \\\end{array}\right]

Notice the extra \\  just before the \end{array} In Latex, this tells latex compiler to insert newline basically.

When opening the latex file using external software, which reads Latex and converts it to GUI, it show this

And now I have to go edit the latex by hand removing the extra \\ (inside the editor I can do global search and replace)

A better outout from Maple's Latex command would be the following

\left[\begin{array}{cc}1 & 2 \\3 & 4 \end{array}\right]

Even though both are valid Latex, the above is better.  I was wondering how hard it is to do this change.

All what the conversion needs to do is just check if the row in the matrix (or Vector) is the last one, and omit the extra \\ at the end of the last row. That is all. 

I could ofcourse write code to try to parse this each time I call Latex and to remove \\ myself in the program, but it will be much easier if Maple automatically did this.

ps. if the Latex conversion source code could be made public, others could help make improvement to it for free, benefiting Maple and everyone using it. Maplesoft would still approve the changes before checkin, and retain the copy right of the source code ofcourse. 

Maple 2020.1

Hello again,   I'm trying to write a procedure to multiply quaternions.   We know that they can be represented as a vector of length 4.   See Wikipedia.   My try  -

qaa=[8,4,6,2] and qab =[2,,4,6,8]
mult:=proc(a,b)

end proc;

maybe needs some looping or data from a table.  

Regards,

Matt

Hello All, is there a command/instruction that can tell me the phase margin, gain margin automatically after I have a bode plot, please?

Units are a neverending story, here's a variant of a problem raised before.

How can i get the minimum of 2 values with Units[Standard] loaded, when one of them could be zero (this loosing its units)?

See also 

• https://www.mapleprimes.com/questions/229640-Units-Disappearing
• https://www.mapleprimes.com/questions/230165-Error-in-UnitsTestDimensions-Invalid
• https://www.mapleprimes.com/questions/230064-Compare-Similar-Units

Download UnitsStandardCompare.mw

Download spatial_1.mw

I want to vary t from -15 to -7 and from 7 to 15 how to write the Explore command?
example : Explore(Fig(t), t=-15..-7 and t=7..15); which does't work.  Thank you.

The center of mass for the density function p(r,θ,φ) = ln(r^2 + θ^2 + φ^2 +1) over the solid sphere radius 2.

I'm not sure how to do this on Maple.  

Many thanks!

Hi friends!

I have the following problem.

I'm trying to generate a matrix given a certain lenght n and a polynomial g(x) of degree r as follows:

If n=10, g(x)=x^4+3x^3+x^2+2x+1 and r=degree(g(x))=4, then the resulting matrix will be

i.e. a matrix with 10 columns, n-r=6 lines, and whose inputs are the coefficients of the polynomial, as follows:

Any help will be very appreciated.

Thank you!

I'm doing som XML readin, and need a bit help in using the HasChild function properly.

The attachment shows that using HasChild on a xmltree works fine, but I can't get i working when using it on a xmldocument. The latter is usually the case when you get when you read in from a file.

HasChild.mw

Hello there, 

Would you please tell me how to re-write the 'PMSM_v_eq' as 'PMSM_flux_eq_desired'? My simple attempt was using the 'solve()' command, but it failed. 

Here is the worksheet:

Thank you!

Download PMSM_eq.mw