MaplePrimes - Questions and Posts tagged with functions

Thanks, and how can I make and use functions f( c[n](t) ) of the basic output c[n](t) of dsolve/numeric, e.g. norm = add(abs(c[n](t))^2,n=1..nn) ?

mjc — Sat, 07 Apr 2012 20:19:55 Z

Sums and cycles with functions in Maple

TaPaKaH — Sat, 07 Apr 2012 18:27:35 Z

At one step of my code I need to define an array of functions which I will later use.

Simplified version of it to highlight the problem:

restart:with(linalg):
procG:=proc(a,b) if a>b then a-b else 0 end if end proc:
F:=vector(2):
for i from 1 to 2 do F[i]:=x->i*procG(x,0) end;

In the actual code array is much bigger and the expression for each function is much more complicated so using the cycle is a real 'must'.

Instead of F[1...

Diagramm: Fit a function one some measured points --> exponential function

Xilyte — Wed, 14 Mar 2012 10:31:45 Z

HI,

I measured some points. This points are plotted in a graph. Now I want to make a fit on this points.

I now that the fit-function has to be like this:

F = A + B1 x e^(-t/C1) + B2 x e^(-t/C2)

Problem: how can I create a fitting function like that?

The best thing I found is the "spline"-fit, but it doesn't work properly. It has to be one lonely function, not a summary of several functions (like spline).

how to compute the modified Mathieu function of besssel I/K type with maple?

yxxu — Wed, 14 Mar 2012 08:45:58 Z

Dear guys,

recently, I met a problem. I need to compute numerically the Mathieu function of bessel I type and bessel K type(Ie,Io,Ke,Ko or denoted by Ce(-q),Se(q),Fek,Gek etc.). That is the mathieu function could be expanded in the series of the modified bessel function I or K. However, I find the commands in maple is very limited, and a question is coming: how to compute these functions with maple?

Thanks for your attention.

yxxu

Plot functions numerically in three dimension

amrramadaneg — Thu, 01 Mar 2012 09:54:32 Z

Hi,

If I have a function defined as

F[i]:=x[i]^2 +x[i]*y[i]+y[i]^2 where x[i]:= (i-1)0.1 and y[i]:=(i-1)0.2 , i=1..100

Approximations to complicated functions

mrask — Fri, 17 Feb 2012 15:35:32 Z

I'm working with some rather complicated functions in Maple. They are elements in matrices, and I need to perform mattrix operations on them, as well as integrations. When I try this with my complete functions, Maple locks up. Therefore I am trying to make approximations to some of the functions. The example below shows an example, where the complicated function (green) is denoted theta24. I comvert it to a 5th degree polynomial (red). But the approximation only...

Solve equation with paramaters in Maple

Scott223 — Sun, 29 Jan 2012 10:13:07 Z

Hi all,

I've got the following Maple math code (its called the 'Strickler function', giving a relation between water hight 'y' in a channel and other paramaters), that works like a charm and correctly outputs my function Q =

> restart;
> A := (b+m*y)*y;
> R := A/(b+2*y*sqrt(1+m^2));
> Q := k*A*R^(2/3)*s^(1/2);

However, all contants in the functions are know, except for 'y' (Q is known as well). How do I solve the last equation for...

how do i plot multiple plots in a graph?

kristen — Tue, 20 Dec 2011 08:20:16 Z

i am plotting multiple plots in one graph using the following commands. This has been successful for a different function but it doesnt work at all for the typed function. can you pinpoint my mistake? maple sheet is attached as well.

> restart;
> w(r):=1+(S)/(2)*[(r^(2)-1)/(2)-4*ln(r)]-(b*S^(3))/(4)*[(r^(4)-1)/(4)+128*((1)/(r^(2))-1)-6*(r^(2)-1)+48*ln(r)]+(3* S^(5)*b^(2))/(8)*[80*(r^(2)-1)-5*(r^(4)-1)-640*ln(r)-640*((1)/(r^(2))-1)+(r^(6)-1)/(6)+256*((1)/(r^(4))-1)];

Contest Success Function

meisje_danst — Sat, 03 Dec 2011 17:47:24 Z

I've found no questions about these types of functions. When I try to solve this equation by using the FOC function and then try to isolate one of the variables 'effort' (or optimal effort) the outcome is about 6 lines of algebra. When I use simplify it expands even further. What other options are there to get a 'nice' expression?

compiled as much as possible expression

icegood — Fri, 25 Nov 2011 13:41:54 Z

Wide set of expressions can convert to compiled functions. Expressions can even include definite integrals.
Hope it helps for others who want really speedup calculations in maple as much as possible for now.

ex.mw

Checked under 15.01 version

Plotting advance Dirac function

TsarStangra — Fri, 25 Nov 2011 02:43:43 Z

I have 2 functions here and I want to study their graphic. I never used Maple for that kind of things but this is probably the fastest and more precise way to see what happens graphically when it comes to those functions:

y1(t) = -rDirac(t) + t^2* summation (from n=0 to infinite) (r^(2n-1) * Dirac(t-2*n*Tau))

y2(t) = t^2* summation (from n=1 to infinite) (r^2n*Dirac(t-(2n+1)*Tau)

Plotting two or more functions in iPad

alorente — Sun, 13 Nov 2011 08:18:13 Z

Is possible to plot two or more functions at the same time in the iPad's application?

Join curves in a plot

tanner87 — Fri, 21 Oct 2011 09:41:59 Z

Hi everyone.

I have calculated three functions which led to three curves in a plot. Since I need to join them so as to create just one curve, I ask you if there's a method, even if approximated. I've thought about an interpolation but I don't know if it's feasible.

Thank you very much.

pointplot arrays

okoolo — Tue, 18 Oct 2011 18:49:28 Z

Hi, I have 2 sets of data:

P := array([1.23, 1.15, 1.10, 1.20, 1.35, 1.25, 1.28, .99, 1.22, 1.25, 1.30, 1.05]);

Q := array([892, 1012, 1060, 987, 680, 739, 809, 1275, 946, 874, 720, 1096]);

p=P(t), q=Q(t) i.e. both p & q are a function of parameter t  t=1..12

2 functions:

x=ln(p)

y=ln(q)

I'm trying to display x against y , ie x=ln(p) on the horizontal axis, y=ln(q) on the vertical

external dll EvalMapleStatement

icegood — Sun, 16 Oct 2011 20:15:40 Z

Call EvalMapleStatement from c dll.

expression always has form like "F(0.4, 0.7, 0.9);" i.e. maple defined function called. All i need it's value without any kind of caching. But memory usage dramatically grows. Help to overcome it!

Tried already EvalMapleStatement ("forget(F);") - do not work. I'm out of ideas what maple also caches. F itself is complicated enought. And not known a priori. How to clear all caches of other functions that f might call?