Looking for faster ways to make chi^2 nonlinear fit calculations, for
functions involving integrals, I have compared timings of calculation of chi^2
at a pair of sample points evaluating the integrals by three numerical
methods. In the attached worksheet they are called as follows:
1. chin, using evalf(Int(...))
2. chin2, using the interpolant option (`dsolve/numeric`(sys, range=...))
3. chin3, using evalf(Int(...,method=_d01ajc))
I have obtained timings with Maple 9.5 using first a Celeron 333 MHz under RH7.1
and then a P4 1.8 GHz under Win XP.
My expectation was that the method of the interpolant function were the

How do I create a shared library for use with the define_external command?

In the examples,ExternalCalling help page the following command is used.

> ssystem("cl test1.c -Fetest1.dll -Gz -link -dll -export:f1"):

But this assumes the Microsoft Visual C/C++ compiler.

I want to use the new Watcom compiler included in Maple 10 for Windows.

Bob.

I'm wondering if a Maple guru would comment on the behavior of Implied Multiplication. I was working through an exercise with Maple and ran into the following behavior. Initially I had this: limit(sum(3((1+3*i/n)^3-2(1+3*i/n))/n, i = 0 .. n), n = infinity) = 231/4 which didn't look right since I expected a different result. Ater messing about I tried looking at the operators and when I did this: limit(sum(3((1+3*i/n)^3-(2)*(1+3i/n))/n, i = 0 .. n), n = infinity) = 195/4 I got the answer I expected to see. [note that Maple Primes has distributed the 2 inside the brackets above. In my document it is 2*(1+3/n)]

When using the FunctionChart call from Student[Calculus1] I keep running into a strange problem. As soon as I attempt to change the display size with the view=[x1..x2,y1..y2] option I get a tiny little graph that is no larger than an ordinary icon. Does anyone have a work around for this? As an example this misbehaves on my Maple 10 install: with(Student[Calculus1]) with(Plots) FunctionChart(x^2, x, view = [-2 .. 2, 0 .. 9]) Tim

In the Help section under procedures (or proc) it states:

argseq - the formal parameter names

I just wondered about the use of the word 'formal'.

eg in this simple Maple code

maxim:=proc (a,b,c,d)

max(a,b)+max(c,d)

end proc:

maxim(2,3,5,4);

. . . the formal parameters are a, b, c, d. Is the word 'formal

' being used as "officially recognised" and a=2, b=3 etc. (ie the

order is important or is there

some deeper meaning? I'd appreciate a short example of a proc using

something else besides variable values, or Null.

Thanks

David

Ok, I have the following equations: c'[t] = a[t]*b[t]*k1 - c[t]*k2, a'[t] = (-a[t])*b[t]*k1 + c[t]*k2, b'[t] = (-a[t])*b[t]*k1 + c[t]*k2, c[0] =0, a[0] =10, b[0] =10. I have data for concentration of "c" at all time intervals from 0-16. Here is the data: {0, 0}, {1, 4.98112}, {2, 6.61986}, {3, 7.42423}, {4,7.89529}, {5, 8.20004}, {6, 8.41008}, {7, 8.56123}, {8,8.67342}, {9, 8.7586}, {10, 8.82442}, {11, 8.87595}, {12, 8.91671}, {13, 8.94923}, {14, 8.97535}, {15, 8.99643}, {16, 9.01351}. I need Maple to Solve the ODE's and optimize the values for k1 and k2 to fit the data usins a least-square method or something along the lins of that. Can someone send me the code for that?

We were wondering if you could help us with a question to Maple:
We have converted a C code directly into Maple code and have found
that Maple runs about a thousand times slower than the C version
(the code is a numerical simulation).
1) Why is this so?
2) How do we make it run faster?

Hi, All,
I'm a Maple primer. I want to solve an ODE numerically and then save the data to file.
I use:
dsol := dsolve({deq,ic}, numeric, range=0..100);
or
dsol := dsolve({deq,ic}, numeric, range=0..100, output=operator);
then how can I print the formated data for some specified t (=1..100, for example) to a data file?
Thanks.
David

I need the symbol for the partial derivative (something like @) in a .mws worksheet. Well, I found this feature as an operator on the new .mw platform, but I need it as a symbol. If I write a name (say PartialD) in the worksheet I want to get the symbol similar to @ at the screen.

What can I do?

Florian

I would like to construct a maplet to evaluate
different objects in general relativity,
say for example , metric,covaliant derivative
and so on. Please help me with
the procedure or a sample maplet.

I'm wondering what I'm missing here: with Student[Calculus1]: InflectionPoints(x^(5/3) - 5*x^(2/3),x) returns an empty result where there should be an inflection point at (-1,-4). I suppose there is a real easy solution to this. Please enlighten me. Tim

When simplifying an expression or solving an equation, is there a way to have Maple display some of the steps without having to put them in manually?

Is it possible to generate C or Fortran code for a numerically evaluated integral (ie. evalf(Int(...)) )?
with(CodeGeneration):
and either C(..) or Fortran(...) yield the error message:
Warning, the function names {Int} are not recognized in the target language
(a similar error message occurs for an int(..) expression)
Alejandro

A student in my PDE class asked about having two functions in animation at the same time. Here is how I suggested doing this:
> f:=(t,x)->sin(t)*x*(1-x);
> g:=(t,x)->cos(t)*x*(1-x);
> N:=50;
> for n from 0 to N do
J[n]:=plot([f(2*Pi*n/N,x),g(2*Pi*n/N,x)],x=0..1):
od:
n:='n':
> plots[display]([seq(J[n],n=0..N)],insequence=true);
Is there a simpler way?
Jim Herod

I am trying to determine when one inequality implies another inequality and I am finding that assume and assuming aren't working consistently for me. I've put the code for my test run below. It seems to work the first time through when I assume mylist[1], but when I assume mylist[2] it always returns false. If I explicitly test is(x>-4) it returns true as it should but if I ask it to determine is(mylist[5]) (which is x>-4 once mylist is overwritten) it returns false? Is there a reason for this? I'm eventually going to need to put it all into a loop that works for any list--is there a way that will guarantee that it will work consistently?