Schurform call from within a procedure...

Hi, I have a small problem. I want to use the Schurform computation in the LinearAlgebra-package. The main objective is to compute the stabilizing solution to a Algebraic Matrix Riccati equation. (perhaps someone knows some code for this?) I call the SchurForm function as (T,Z) := SchurForm(A,output=['T','Z']) where A has the correct type (ie complex(sfloat)). This works well in a Maple sheet, but in a procedure (where T and Z are defined local) the kernel says that the output chosen is invalid. If I don't specify any output, it also works good (but then I get no Z). The Maple version is 10 and I am using Linux.

Slow numerical entry...

On a whim I decided to write a routine to numerically calculate the volume of a sphere and compare the result with the well known formula (4/3)*Pi*r^3. What struck me was how slow the MAPLE code ran compared to the same code in VB. I realize that a program like MAPLE which is geared toward symbolic mathematics would not be expected to be as fast at numerical calculation as other vehicles, but I was struck by the difference. Below is the code in VB and MAPLE. Both routines give the same answer. The MAPLE roputine runs about 10 times slower than the VB routine. I was wondering - perhaps I'm not being fair to MAPLE. Is there some way I could have written the code to run significantly faster?

linear regression in 3d...

I have data of the type xyz-coordinates. How do a fit a line to it? Thanks

Eigenvector Problem Revised...

I was trying to use the LinearAlgebra package to discover the eigenvalues and eigenvectors of the 2x2 matrix representing a rotation in the x-y plane. The matrix [[cos(theta)|-sin(theta)],[sin(theta)|cos(theta)]] However the function, Eigenvectors does not work with this matrix, and the function Eigenvalues returns the eigenvalues of the trasformation but not in the usual complex number notation. Can anyone help with explaining and or resolving this ? v/r, Dan

Installation error...

Hi I have tried installing Maple 10 on both by Desktop and laptop both of which are running XP SP2. It fails in both cases giving an error about an unknown user interface. "Unable to preprare and load the installer in GUI mode" Any ideas guys? Cheers, Moz!

Rays from a uniform point and changing location of...

I have the following maple file. Is it possible to instead of having the incoming rays at a vertical at intervals along the x axis, whether to have them emerging from a single point on the y axis, and also whether this point can moved up and down the y axis. Thanks View 3259_mirrorplot.mw on MapleNet or Download 3259_mirrorplot.mw
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Strange result when calculating Mean symbolically...

I am trying to use the Mean command of the Statistics package to calculate the arithmetic mean of a transformed random variable symbolically. I am using Maple 10. In my case the Mean command gives an incorrect answer. First a simple example, which gives me a correct result symbolically: restart;with(Statistics): X:=RandomVariable(Uniform(-Pi, Pi)); Mean(X+a);#it gives a, it is ok. #and here is my more complicated problem: restart;with(Statistics):X:=RandomVariable(Uniform(-Pi, Pi)); assume(Gt::RealRange(Open(0),Open(1)),Gr::RealRange(Open(0),Open(1))); Mean(abs(1-Gt*Gr*exp(-I*X)));

Mirroring Probabilities...

Hi, I have three equations Y=f(t) with each equation corresponding to a probability as shown below. Y1=f(t) with probability of 0.05% Y2=f(t) with probability of 5% and Y3=f(t) with probability of 50% If we assume that these probabilities belong to a normal distribution how can I work out the equations for 99.95% and 95%probability.In other words I would like to mirror Y1 and Y2. The idea is to plot all the equations of 0.05%,5%,50%,95% and 99.95% probability in the same plot and create a 3D surface where the axis will be Y,t and P(probability) or even better generate the equation of P=f(Y,t) that will describe this surface.

The restart command does not work correctly?

by: Maple
This example shows that restart command does not work correctly - it means that it does not clear stack memory(internal memory). The following example shows it. In that procedure there are some mistakes, but I think that the restart command should work correctly whith them. If you execute the following procedure three times (maybe twice, it depends on the computer memory capacity, but I do not amount to more than three times), the Maple system falls down with out of memory (execution stop - the stack ) - why? You call the restart command, so where the fatal error is. It does not depend on the correct usage of statements in the procedure.

merging arrays...

I have a list of arrays which I would like to merge into a single array. In the case of two arrays (say A and B) I basically want maple to dump them both into a new array in which wherever A[i,j]<>B[i.j] the new array takes whichever is nonzero and if A[i,j]=B[i,j] does nothing. is there any short way of doing this without writing a function which runs through the arrays and compares each element induvidually and outputs the results into a new array?

sqrt(x^2)...

If you ask most people "what is the square root of 64?" they will answer "8". Of course we know that the technically correct answer is {8,-8}. So I'm a bit confused that when I ask MAPLE to simplify sqrt(x^2) it spits the expression right back to me, but when I tell MAPLE to give me sqrt(x^2) assuming x>0 it gives me x. It seems to me that there are going to be two answers whether or not x>0. That is, the answer to sqrt(x^2) is {x,-x} whether or not x>0. That is, sqrt((-8)^2) = sqrt(8^2) = {8,-8}. So when I am using symbols rather than numbers why does MAPLE give me the answer x for sqrt(x^2) assuming x>0, but give me the answer sqrt(x^2) when I don't include the assumption?

do loop construction...

Is there a secret to entering a do loop construction in Maple? I have tried constructing a simple do-loop involving several different statements under one loop. The problem is, every time I try to enter the first line of the loop, the "for i=...do ", I get an error message indicating "Unterminated loop". I guess it is looking for the "end do" statement but I wish it to end only after several statements have been executed within each cycle of the loop. This must be really trivial but I'm new to this so.. Thanks.