Hi, I'm looking for a list of all non-isomorphic graphs of small order (on say at most 9 vertices), ready to use in the networks package. Does anyone know if there is such a list out there? Thanks.

This is a follow-up to an earlier post about CovarianceMatrix.

There are several ways in which Statistics:-CorrelationMatrix can be improved.

CorrelationMatrix shares some inefficiencies with CovarianceMatrix, by computing correlations between the n columns, pairwise. But in doing so it also computes...

Hello eveyone,

I'm experiencing a frustrating problem, trying to get maple to solve a system of differential equations. I have defined my system as:

f:=1-2*(n+1)*b*xi^2*nu(xi):

sys:={diff(nu(xi),xi)=(theta(xi)^n - 3*nu(xi)), diff(psi(xi),xi)=(n+1)*b*xi*theta(xi)^n*(1+b*theta(xi))/f, diff(theta(xi),xi)=-(nu(xi)+b*theta(xi)^(n+1))*xi*(1+b*theta(xi))/f, theta(xi=0)=1, nu(xi=0)=1/3};
 

The only part worth concentrating on is the part I've made bold. I then can solve the system near xi=0 witha  series solution:

Hi there,

I have a 2-D ODE system. Objective: plot the nullclines and phase diagram around the equilibrium point. Problem: one of the ODEs has an integral and a call to DEtools[dfieldplot] returns:

Error, (in DEtools/dfieldplot) extra unknowns found

I have created a minimal example below.

Hi! This tutorial contains two examples that show you how to determine the equation of the best (least-squares) fit of a function to a set of data points. It also shows you how to apply Maple's Curve Fitting Assistant to display a graphical representation of the line or curve of best fit.   Wat

Maple's package DiscreteTransforms is a bit skinny, I miss various ones like discrete cosine transforms (at least the most 4 types), sine transform, Hartley transform, z-transform and may be the fractional Fourier transform or symmetric FTs (not sure for the whole herd).

It should be available, if Maple wants to be a numerical tool for technical users (all kinds of engineering I would say): it would not make sense for them to use other libraries, compile and finally combine with Maple, because it does not have it.

It seems like everywhere you turn lately, people are talking about how to be kinder to the planet. One example is just how much interest was generated when GM unveiled its plans for the Chevy Volt last year. As I write this, 46,527 people are on the waiting list for the upcoming electric car, which is scheduled to be released in late 2010 as a 2011 model. At my house, we wash our clothes in cold water; use a programmable thermostat; turn off the lights when we’re not in a room; recycle and compost our waste; use a low flush toilet, energy efficient appliances, and an electric lawnmower; and of course, snuggle our two dogs for warmth!   

Yesterday was one of those remarkable days when everything seems just about right. The highlight was an email message I received from a Prof. Fang from Ryerson University notifying us that we had been both nominated and awarded the Omond Solandt Award by the Canadian Operational Research Society for ongoing and outstanding contribution to the field of Operations Research (OR). No, it’s not a Nobel Prize or an Oscar, but whenever a group of smart people publically recognize our work, the honor and pride are genuine.

I found that the solve command doesn't work properly with some systems of equations containing radicals. For xample: solve({b = RootOf(_Z^3+c^2+1),c = RootOf(_Z^2+_Z+1), b = RootOf(_Z^3-RootOf(_Z^2+_Z+1))}); doesn't return any results and no "_SolutionsMayBeLost" warning. But using solve(convert({b = RootOf(_Z^3+c^2+1),c = RootOf(_Z^2+_Z+1), b = RootOf(_Z^3-RootOf(_Z^2+_Z+1))},radical)); solves the system. What can be done about it to avoid such situations?

I thought I’d exercise my left brain a little with this post and write on something a bit more technical. Actually, this was triggered by a chat I had over dinner last night with our 3D graphics development manager and a client. As you may have guessed math is intimately related to computer graphics of all sorts. My PhD thesis so many years ago was on the topic of creating funny surfaces that smoothly join two complex surfaces with a relatively small number of shape control parameters: such surfaces are called blend surfaces. This required the development of a bunch of algorithms that related either implicitly defined surfaces (i.e. f(x,y,z) = 0) or parametrically defined surfaces (i.e. each point is defined by the triplet (x(t), y(t), z(t)) ). That was twenty years ago and I always thought that any problem that I was wrestling with would have been resolved twice over by now. My ego was pleasantly surprised that indeed such problems are still the stuff of heated debates and vigorous research.

This function

f(x) = { 0,           x = 0
          { 1 - x,      0 < x < = 1

is not continuous on [0, 1].

So I wrote

f := x -> piecewise (x = 0,0,x > 0,1-x);
plot(f,0..1);

But Maple doesn't show the lack of continuity. (discont=true doesn't do anything here). Can I improve the plot?
 

Alla

Titlefont affects other text elements in an animation. Here is an example.

First, without an animation (works OK, ignoring such things as the plot being higher at 0 than it should, having too many ticks on the y axis, the plot being located too far from the title etc., which are different topics),

For almost 20 years, Math education has been recognized as the first killer application for symbolic computing. By taking out the grunt work of manipulating equations, calculating integrals and performing matrix computations with symbolic entries, systems such as Maple have transformed the math classroom.

I always have problems to simplify some complicated expressions to simpler ones. Here is an example of those: > A := exp(w*a)*w^2*epsilon1*epsilon2+exp(w*a)*w*epsilon1*s2-exp(-w*a)*w^2*epsilon1*epsilon2+w*s2*epsilon1*exp(-w*a)+exp(-w*a)*s1*epsilon2*w-s2*s1*exp(-w*a)+s1*exp(w*a)*epsilon2*w+s1*exp(w*a)*s2; > B := (w*epsilon1*((1+exp(2*w*a))*s2+(-1+exp(2*w*a))*w*epsilon2)+s1*((-1+exp(2*w*a))*s2+(1+exp(2*w*a))*w*epsilon2))*exp(-w*a); > simplify(A-B); 0

I got some expression but do not know how to get the simplest form by using simplify > C := -(1/2)*exp(-I*omega0*t)+(1/2)*exp((-beta-I*omega0-I*alpha)*t); > Csq := evalc(conjugate(C)*C); > simplify(Csq); -(1/2)*cos(omega0*t)*exp(-t*beta)*cos(omega0*t+t*alpha)+1/4-(1/2)*sin(omega0*t)*exp(-t*beta)*sin(omega0*t+t*alpha)+(1/4)*exp(-2*t*beta) which obviously should be equal to 1/4*(1+exp(-2*t*beta)-2*exp(-t*beta)*cos(t*alpha)). How can I get this form using Maple?