choosing lightmodel=none and shading=none, produces a dark grey grided surface
plot3d(x*y, x = 0 .. 10, y = 0 .. 10, lightmodel = none, shading = none)

adding the style=wireframe option gives a blank plot.  Grid probably white?  Changing style to patchnogrid the surface is indeed white. However chosing both shading and style options to none regardless of the lightmodel will produce a plot that appears empty.  Is this to be expected?

However, just the style=wireframe option produces a colored grided wireframe as to expect
plot3d(x*y, x = 0 .. 10, y = 0 .. 10, lightmodel = none, style = wireframe)

Hi.

I'm working on an electronics project currently. In that project I have been trying to solve a system of inequalities, as shown by the picture from Maple below:

restart;

R__1 := 1;
lign1 := V__i/(R__4*(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4)) = C*(k__1 - R/R__C + R);
lign2 := V__i*(1/R__1 + 1/R__4)/(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4) = C*(k__2 - R/R__C + R);
lign3 := V__i*(1/R__2 + 1/R__4)/(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4) = C*(k__3 - R/R__C + R);
lign4 := V__i*(1/R__3 + 1/R__4)/(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4) = C*(k__4 - R/R__C + R);
lign5 := V__i*(1/R__1 + 1/R__2 + 1/R__4)/(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4) = C*(k__5 - R/R__C + R);
lign6 := V__i*(1/R__1 + 1/R__3 + 1/R__4)/(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4) = C*(k__6 - R/R__C + R);
lign7 := V__i*(1/R__2 + 1/R__3 + 1/R__4)/(1/R__1 + 1/R__2 + 1/R__3 + 1/R__4) = C*(k__7 - R/R__C + R);
solve({lign1, lign2, lign3, lign4, lign5, lign6, lign7}, [R__4, R__2, R__3, R__C, R, C, V__i]);

Here's a picture as well:

However, the solution is simply that V_i = 0 and C=0, which is not really helping me. Am I doing something wrong here or is my system of equalities simply unsolvabe?

How to learn Maple Programming effectively, whether Python will help?

My objective is to write a procedure that will read data from xml at different mentioned condition, read ICBO value at different condition of VGS i.e ICBO value at VGS=5V

BJT_ICBO := proc(parsedXML, VGS at condition )
 

end proc;

can some one help me to write procedure 

Hi, can someone explain me why CodeGeneration in C throws the error : Error, (in Print) improper op or subscript selector ? Interestingly, CodeGeneration in Python or Matlab works. Source code is attached. Thanks in advance!

membrane_energy.mw
 

Download membrane_energy.mw

Hello,

I obtained a mode shape from a vibration problem.

I want to normalized mode shape for the comparison of responses corresponding to different modes.

How I can normalize the mode shape that provided in the maple file?

The figure corresponds to this mode shape is plotted that is attached.

Thanks

mode_shapes.mw

Download mode_shapes.mw

Download mode_shapes.mw

I'm using variable names that have subscripts, not as a table index but literal i.e. R__1 as a unique variable name.  It seems whenever I make assumptions on variables that have subscripts, when I use them the variables that have subscripts are printed twice:

Can anyone explain why this happens and how to get around it?

Thanks in advance.

Is it italic when copied and pasted?  Is it bold when copied from maple 8?  I just ahve not been able to work it out.

The only way that I can think of doing it is by multiplying by a tetrad.  Even then it does not work well see my worksheet:  The Dirac Equation in Robertson-Walker spacetime.

HI

I am using a simple piece of code to generate Lie derivatives, and I am interested in adapting it so that I can use it with vector Fields where that include RootOf expressions. 

LieDer_with_rootof.mw

The above includes an example where it works, and an example where RootOf appears in the vector field and it does not work. 

Help me to solve this problem with pdsolve

Hello,

I am Seonhwa Kim, a mathematical researcher in Korea. Recently, I have extensively used Maple to compute character varieties of 3-manifolds. Several months ago, I obtained some strange results in Maple which implies a contradiction in theory.  I have been struggling with these issues since it is usually about enormous polynomial systems.  Eventually, I could figure out that the issues are caused by a defect in Maple and were able to construct a minimal working example to produce wrong computations in Maple.  I am writing this post to report them.

This is mainly about the PolynomialIdeal package.  Along with the documentation in Maple, If an ideal J is radical, PrimeDecomposition and PrimaryDecomposition should have the same result.  But, as we see the following, the result of PrimeDecomposition and PrimaryDecomposition are different although J is a radical ideal.

The problem seems to be that the PrimaryDecomposition command in Maple sometimes produces incorrect results.

We can compute the primary decomposition of J by hand.  It should be <x> and  <y, x-1>.

I double-checked this by the other software;Macauley2, Singular, and Magma, for example, you can see it as follows.

Secondly, not only for PrimaryDecomposition but also PrimeDecomposition may produce an incorrect result.

Here is a minimal working example.

Maple tells us a compatible result of prime and primary decomposition of a radical ideal J.

But the first component of J,  < b-1, c-a+1 >, contains the third component < a, b-1, c+1 >.

It contradicts with the definition of Primary decomposition. So the correct answer should be  < b - 1, c - a +1 >, <a,b,c>.

I also checked that  Macaluey2, Singular and Magma. They all say that my hand computation is correct. as follows.

I have used Maple 2017 by the license of my institute (Korea Institute for Advanced Study).

When I noticed these defects, I thought it would be fixed in the newest Maple version.

So, I have tried my examples by Maple2019  free trial, but It also has the same problem. 

I guess this problem is not reported or recognized yet. 

I hope this problem will be fixed as soon as possible.

Thank you for attention.

Sincerely,

Seonhwa

Hello, I'm using free 15 day trial Maple 2019.2 on my Macbook (Macos 10.15.3).

I can't work Maple. I enter some inputs (2+3) and press enter. It works. But when I write plot, version(), f, sin.. or something else it didn't works. And no response. When I click enter, nothind happen. What is the problem? Please help me.. 

Hi everyone,

When my cursor is on an output, the paragraph style changes to 2D Output, as it most likely should. When I then go to a new executable line, it takes forever for all of my expressions to "light up" (meaning that it takes a while for me to be able to use them), and it takes forever for the paragraph to go from 2D Output to 2D Math.

I sadly don't remember when this happened, or what might have caused it, but if any of have any suggestions or answers, I'd greatly appreciate it.

Thanks for listening,

A confused highschool student.

In graph theory, the crossing number cr(G) of a graph G is the lowest number of edge crossings of a plane drawing of the graph G. I'd like to use maple to compute crossing number of some graphs (any graphs is ok,  for example： cr(K5)=1 ). Someone can help me ? thanks. 

I know the problem of computing the crossing number is NP, but I guess we have some good  ways to compute in some small graphs.