MaplePrimes - Questions and Posts tagged with parameter

Curve fitting on multiple data series

doucet — Mon, 25 Feb 2013 19:53:17 Z

Hello,

I have two sets of data representing two function that depends on x with a parameter A.

I need to do a fit on both data series at the same time so to fit with the best parameter A.

Here is how I do a fit on one function

> f(x):=A*cos(x-B)^(2);

> g(x):=A*(cos(x-C)^(2)+ sin(x-C)^(2))^2;

> fit1 := Fit(f(x), r, x, parameternames = [A, B, C...

How do i print to PDF the parameters of a model in a parameter block on maplesim?

JotaTR — Sun, 27 Jan 2013 16:07:23 Z

I have a model with 3 parameter blocks containing a lot of constants. I would like to know how can i print those lists to papper, .pdf, word or something like that.

Thanks

problem with function solve

auetienne — Mon, 07 Jan 2013 17:09:01 Z

Hi,

I am trying to solve the following system using the function "solve", but the message "warning solutions may have been lost" appears.

This is my script (a,b,c,d,e,f, Resp, Malcyt,Pyrcyt are parameters). The unknown variables are Citcyt, Citmt,Malmt,Pyrmt:

e1 := 0 = a.Pyrcyt-a.Pyrmt+(b-c).Malmt;
 e2 := 0 = d.Malcyt+e.Citmt-(d+b+c).Malmt;
 e3 := 0 = f.Citcyt+c.Malmt-(e+f).Citmt;

 e4 := 0 = 2.*e.Citmt+(b+c).Malmt-Resp;

Procedure inputs??

casperyc — Sun, 16 Dec 2012 19:01:54 Z

Hi all,

I read the help on using parameters, then I tried to modify the example

f := proc(a, b, c)

    if _params['b','c'] = NULL then
    a
    elif _params['c'] = NULL then
    a + b
    else
    a + b + c

    end if

end proc:

I can't really spot where it went wrong, but it just wouldnt execute as I would expect...

Correlation coefficient for system of nonlinear differential equations and data

kierstejn — Wed, 12 Dec 2012 19:35:44 Z

Hey guys..

I need some help on determining the correlation coefficient between my data points for an Influenza epidemic and the SIR model, with my estimated parameters Beta and Alpha. The initial conditions for the equations are defined at the beginning of my worksheet:

SIR_model.mw

Hope someone can help me ;)

Graphing parametric sweep results of a MapleSim model in Maple

Onnimikki — Fri, 07 Dec 2012 16:13:34 Z

Hi,

I'm running a 2D parameter sweep from Maple 15 on a MapleSim 5 model. The output is stored in a 2D matrix. I've encountered two problems:

1) when I graph it with matrixplot the z-axis values are fine but I can't figure out how to change the x-axis and y-axis values from the matrix indices to the actual values of the swept parameters.

2) When the parameter sweep begins I get a warning about storing the values in a matrix. Maple...

Is it possible to have parameters in a parameter box that depends on others?

JotaTR — Tue, 20 Nov 2012 20:03:36 Z

I would like to know if it is possible to declare some variables in one parameter box (i would call it independ parameters) and other with parameters that depends on the first ones:

L=5

m=2

k=arctan(m/L)

(for exemple)

THanks

Can I make variables appear in DSolve numeric output

brian bovril — Sun, 18 Nov 2012 12:37:54 Z

numeric_de.mw

hello boffins

if my de was soluble analytically, I would get an expression of time in terms of the other variables (V,theta,x) easily, but because it is only numerically solvable, i get an expression x(t)=proc(t)...,- the variables V and theta are mixed up in it-. Is there anyway they can appear?

I know I can put numerical values on V and Theta (and x) and solve for time (using parameters...

Find all unknowns (parameters) from an expression (vector)

casperyc — Tue, 13 Nov 2012 21:51:58 Z

Hi all,

Is there a quicker way to find all unknows from an expression?

unknowns.mw

Say I want a list contains ALL parameters. In this case, it would return

[w1,w2,mu,tau[2],tan[3],tan[4],eta[1],eta[2]]

Is there a way to do this?

Thanks!

Casper

Formulate equation with different classes (categories) & subscripts

casperyc — Tue, 13 Nov 2012 15:47:31 Z

test.mw

Hi all,

Here is the problem, I will try my best to describe it:

Firstly of all,

log(p[j,c]/(1-p[j,c]))=mu+tau[j]+eta[c];

In this system, the 'j' is a time varying parameter, and the...

Vectors (Column, Row, Notation, VectorCalulus)

casperyc — Thu, 08 Nov 2012 23:21:40 Z

restart:

with(LinearAlgebra):
with(ArrayTools):

k:=4;
pA:=<seq(p[a,i],i=2..(k+1))>;
pB:=<seq(p[b,i],i=2..(k+1))>;
pA+pB;

with(VectorCalculus):

pA:=<seq(p[a,i],i=2..(k+1))>;
pB:=<seq(p[b,i],i=2..(k+1))>;
pA+pB;

Hi all,

After I loaded the package with(VectorCalculus), the output of vectors changed to a different one.

Is there any real "difference" when...

Graphing and parameter sensitivity analysis in maple 16

rmbogo — Mon, 05 Nov 2012 08:28:14 Z

Please help me plot the graphs of the following equations:-

eq1 := diff(E[X(t)], t) = lambda-delta*E[X(t)]-beta*E[X(t)*V(t)];

 eq2 := diff(E[Y(t)], t) = -delta*E[Y(t)]+beta*exp(-rho*tau)*E[X(t)*V(t)];
                                                    
eq3 := diff(E[V(t)], t) = gamma+N*kappa*E[Y(t)]-mu*E[V(t)]-beta*E[X(t)*V(t)]

NB:- E[X(t)]= the expected value of variable X at time t.

Please help me know how to input this...

Calculate percentage change in a solution?

J4James — Thu, 18 Oct 2012 05:25:26 Z

I have a differential equation having a parameter say 'a'.

If I increase 'a' by 10%, got change in the solution as well.

How to calculate change in percentage in the solution?.

Thanks

Plotting the Parameters that cause a D.E. Event to Execute

jschulzb — Mon, 08 Oct 2012 17:09:47 Z

Hi,

So I've got a numerical solution to a D.E. and want to find which parameters (v, theta) cause the second event to occur. Here's my dsolve

> soln:= dsolve({eqx, eqy, inty, intx, x(0)=0, y(0)=0}, {x(t), y(t)}, numeric, method = rkf45, output=listprocedure, parameters=[v, theta], events=[ [ [diff(y(t),t)=0, y(t)

The first event is "Does the trajectory reach its max at a height less than 3.05m? If so, stop computation"...

Invalid operator parameter name

mzh — Wed, 26 Sep 2012 16:30:31 Z

Dear Maple users

Please help me correct this input:

> f := (c[A], c[B]) -> c[A]+c[B];
Error, invalid operator parameter name
    f Assign Typesetting:-mambiguous(

      (c[A]comma c[B]) rarr c[A] + c[B], 

      Typesetting:-merror(invalid operator parameter name))
>

In Maple, c[A] is actually "c subscript A".

Thanks for help.

PS: Is...