Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

Hey, how is can i see all the steps in maple? I would specially like to know it for differential equations.

For example we could use this one:

dl := 3*(diff(y(t), t, t))+6*(diff(y(t), t))+4*y(t) = 0 

I'd like to implement this in Maple, but being a newbie having hard time getting the syntax right:



This is what I tried:

a:='a';
f:= i->product( `if`(evalb(i<>j),(a-z(j))/(z(i)-z(j)),NULL),j=1..3);

but it is not skipping the i=j case, since when I call it with f(1) I get division by zero.

f(1);
Error, (in product) numeric exception: division by zero

Tried also

f:= i->product(`if`(evalb(not(i=j)),(a-z(j))/(z(i)-z(j)),NULL),j=1..3);
and few other things. I think the reason it fails is deeper than my level of Maple undertstanding.

How would you do this in Maple?

I came across this website www.fuelsonline.ca that has their price for furnace oil and Propane.  I thought it would be fairly easy using HTTP[Get] to fish out the prices, but it turns out those values on the page are images in of course a format (PNG) that cannot be read by Maple.  I don't know where that web page is pulling the prices from but it looks like web surgery with Maple will be unable to (at least not easily) wean the numbers out. 

If anyone has any ideas I would be interested in knowing.

Hi,

I have two all 1.-1  square matrices and want to test whether they are equivalent or not. Can anyone help me with details?Thanks in advance

 

Hello everybody

I am working on the bending of FGM plate, and I just used maple for the calculation functions of my problem of the bending of FGM plates.

Can any from the members of mapleprimes one help me to write Navier's equation include below for the bending of the plate because I am new in using Maple 18

alfa=m*pi/a, beta=n*pi/b with m=1,3,5..100 and n=1,3,5...100

Thank's for all 

Bending

Hi gang!
Upon upgrading to a stable mac OSX Yosemite, I've been experiencing a noticeably slower Maple 18. The Maple machine itself is quick during calculus operations, though the interface bugs me after the upgrade.

It seems as if the program constantly has to load any open palettes. So for an example, if I run with the 'expression' and 'calculus'-palettes open - which I do constantly - it seems as if Maple has to load every single icon, piece by piece. This loading occurs randomly, but often it happens several times every minute. The loading causes a 3-4 sec lag, which is incredibly annoying. Closing the paletts does not affect this random loading. I run with the recent Java-upgrade specifically for Yosemite.

Before upgrading, I ran Maple 18 on 10.9 Mavericks and everything worked ran like a dream. The program was incredebly fast and responsive. Furthermore, I run Maple on a late 2014 fully specced MBP, so hardware shouldn't be an issue either.

My Maple is installed with an authorized academic license.

 

Anyone able to give some inputs to what might seem to cause the issue here?

Thanks a bunch! :-)

 

Best regards,

Claus Iversen

Denmark

 

 

Dear Friends,

My present problem is to calculate the coefficients  

of ODES based on the experiment data. In order to simulate the actual experiment, a set of  is given with . Then the experiment data (yexp) can be calculated. Finally, the least-squares method (lsq) is used to calculate the coefficient values. Now the NLPSolve function can be used. However, the globalsolve cant run.

 

If it is convenient for you, wish you can solve it.

 

Code:

 

restart;
cdm_ode := diff(y1(t), t) = c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(1-y2(t)), diff(y2(t), t) = ks*y2(t)^(1/3)*(1-y2(t)), diff(y3(t), t) = h1*(1-y3(t)/h2)*c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(sigma*(1-y2(t))), diff(y4(t), t) = (1/3)*kp*(1-y4(t))^4, diff(y5(t), t) = A*B*y1(t)^(B-1)*c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(1-y2(t)), diff(y6(t), t) = y6(t)*c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(1-y2(t));

 

tol_t := 3600;
sol := dsolve([cdm_ode, y1(0) = 0, y2(0) = 0, y3(0) = 0, y4(0) = 0, y5(0) = 0, y6(0) = 175], numeric, range = 0 .. tol_t, output = listprocedure, parameters = [c0, n, sigma, s0, ks, h1, h2, kp, A, B]);

sol(parameters = [5.7*10^(-6), 10.186, 175, 200, 5*10^(-8), 10000, .269, 1.5*10^(-7), 1.5, 2]);

t := [seq(i^2, i = 0 .. 50, 1)];

y1data := subs(sol, y1(t));
 
y1exp := [seq(y1data(t[i]), i = 1 .. 51)];

err := proc (c0, n, s0, ks, h1, h2, kp, A, B) local y1cal, y1val, lsq; sol(parameters = [c0, n, 175, s0, ks, h1, h2, kp, A, B]); y1cal := subs(sol, y1(t)); y1val := [seq(y1cal(t[i]), i = 1 .. 51)]; lsq := add((y1val[i]-y1exp[i])^2, i = 1 .. 51); lsq end proc;

with(Optimization);
val := NLPSolve(err, 10^(-8) .. 10^(-4), 2 .. 20, 150 .. 250, 10^(-2) .. 1, 100 .. 20000, 10^(-5) .. .4, 10^(-5) .. 1, .5 .. 2, 1 .. 10);
GlobalSolve(err, 10^(-10) .. 10^(-4), 2 .. 20, 150 .. 250, 0 .. 1, 100 .. 15000, 0 .. .5, 0 .. 1, .5 .. 2, 1 .. 5);


Error, (in GlobalOptimization:-GlobalSolve) `InertForms` does not evaluate to a module

 

 

 

 

 


#DeHoog f4(t)

F4 := proc (F::procedure, Tol, M, t) local T, gamma1, Fc, e, q, d, A, B, i, r, m, n, h2M, R2M, A2M, B2M, a, z; T := evalf(2*t); gamma1 := evalf((-1)*.5*ln(Tol)/T); Fc := Array(0 .. 2*M); e := Array(0 .. 2*M, 0 .. 2*M); q := Array(0 .. 2*M, 0 .. 2*M); d := Array(0 .. 2*M); A := Array(-1 .. 2*M); B := Array(-1 .. 2*M); Fc[0] := evalf(.5*F(gamma1)); for i to 2*M do a := gamma1+I*i*Pi/T; Fc[i] := evalf(F(a), 25) end do; for i from 0 to 2*M do e[0, i] := 0 end do; for i from 0 to 2*M-1 do q[1, i] := evalf(Fc[i+1]/Fc[i]) end do; for r to M do for i from 2*M-2*r+1 by -1 to 0 do if 1 < r then q[r, i] := evalf(q[r-1, i+1]*e[r-1, i+1]/e[r-1, i]) end if; if i < 2*M-2*r+1 then e[r, i] := evalf(q[r, i+1]-q[r, i]+e[r-1, i+1]) end if end do end do; d[0] := Fc[0]; for m to M do d[2*m-1] := -q[m, 0]; d[2*m] := -e[m, 0] end do; z := evalf(exp(I*Pi*t/T)); A[-1] := 0; B[-1] := 1; A[0] := d[0]; B[0] := 1; for n to 2*M do A[n] := A[n-1]+d[n]*z*A[n-2]; B[n] := B[n-1]+d[n]*z*B[n-2] end do; h2M := evalf(.5+((1/2)*d[2*M-1]-(1/2)*d[2*M])*z); R2M := evalf(-h2M-h2M*sqrt(1+d[2*M]*z/h2M^2)); A2M := A[2*M-1]+R2M*A[2*M-2]; B2M := B[2*M-1]+R2M*B[2*M-2]; evalf(exp(gamma1*t)*Re(A2M/B2M)/T) end proc;

proc (F::procedure, Tol, M, t) local T, gamma1, Fc, e, q, d, A, B, i, r, m, n, h2M, R2M, A2M, B2M, a, z; T := evalf(2*t); gamma1 := evalf((-1)*.5*ln(Tol)/T); Fc := Array(0 .. 2*M); e := Array(0 .. 2*M, 0 .. 2*M); q := Array(0 .. 2*M, 0 .. 2*M); d := Array(0 .. 2*M); A := Array(-1 .. 2*M); B := Array(-1 .. 2*M); Fc[0] := evalf(.5*F(gamma1)); for i to 2*M do a := gamma1+I*i*Pi/T; Fc[i] := evalf(F(a), 25) end do; for i from 0 to 2*M do e[0, i] := 0 end do; for i from 0 to 2*M-1 do q[1, i] := evalf(Fc[i+1]/Fc[i]) end do; for r to M do for i from 2*M-2*r+1 by -1 to 0 do if 1 < r then q[r, i] := evalf(q[r-1, i+1]*e[r-1, i+1]/e[r-1, i]) end if; if i < 2*M-2*r+1 then e[r, i] := evalf(q[r, i+1]-q[r, i]+e[r-1, i+1]) end if end do end do; d[0] := Fc[0]; for m to M do d[2*m-1] := -q[m, 0]; d[2*m] := -e[m, 0] end do; z := evalf(exp(I*Pi*t/T)); A[-1] := 0; B[-1] := 1; A[0] := d[0]; B[0] := 1; for n to 2*M do A[n] := A[n-1]+d[n]*z*A[n-2]; B[n] := B[n-1]+d[n]*z*B[n-2] end do; h2M := evalf(.5+((1/2)*d[2*M-1]-(1/2)*d[2*M])*z); R2M := evalf(-h2M-h2M*sqrt(1+d[2*M]*z/h2M^2)); A2M := A[2*M-1]+R2M*A[2*M-2]; B2M := B[2*M-1]+R2M*B[2*M-2]; evalf(exp(gamma1*t)*Re(A2M/B2M)/T) end proc

(1)

F4(proc (p) options operator, arrow; int(12*Dirac(a)*BesselJ(0, 2*a)/(a*p), a = 0 .. .100) end proc, 0.1e-4, 4, 10);

Float(undefined)

(2)

``

``


Download dehoog.mw

How is it possible to numerically integrate the function containing Diract delta function.

The following code for example is failed to answer and makes computer memory full.

 

       

 

 

I have a fairly old laptop, a Toshiba S10 Tecra, windows 7 64 bit and 4 Gb RAM.  It has an NVidia Quadro NVS 150m video card inside and according to NVidia CUDA capable of a compute level to 1.1 which is ok for float[4] but not float[8].  Inititiating the computecabability in maple does indeed bring a score level of 1.1.

Doing any LinearAlgebra matrix calculations with CUDA enabled is maybe 5x's slower than with it disabled.  I run into BLAS errors and screen blankouts at matrix values of 2000.  The video driver is the latest from Toshiba (2010) but not NVidia (2014) I suppose there would be an increased performace with newer drivers but if I'm going to run into the same issue of slower calculations with CUDA enabled there's no point in even testing the newer drivers on an otherwise fine running machine. 

Since it is a low end video card is CUDA even worthwhile, will I even notice a speed up with updated drivers?

                                                                          

Dear Maple Experts,

i am new to maple and I am trying to write a maple algorithm in order to calculate the GCD of two functions. 

I have defined the two functions and written the algorithm, but I get an error "Unable to Parse".

Here is my code:

restart; with(Algebraic); with(LinearAlgebra[Generic]); with(RegularChains); with(FastArithmeticTools); with(ChainTools); interface(rtablesize = 15);

f := (y^2-1)*((y+1)*x^4+(y^2-1)*x^3+(y^3-1)*x^2+(y^4-1)*x+y^5-1);

g := (y-1)*x^5+(y^2-1)*x^4+(y^3-1)*x^3+(y^4-1)*x^2+(y^5-1)*x+y^6-1;

SubRes:=proc(f,g,var): local  i,a, delta, beta, psi: if degree(f,var)<degree(g,var) then a[0]:=Algebraic:-PrimitivePart(g,var): a[1]:=Algebraic:-PrimitivePart(f,var): else a[0]=Algebraic:-PrimitivePart(f,var): a[1]:=Algebraic:-PrimitivePart(g,var): fi: delta[0]:=degree(a[0],var)-degree(a[1],var): beta[2]:=(-1)^((delta[0]+1)): psi[2]:=-1: i:=1: while a[i]<>0 do a[i+1]:=(prem(a[i-1], a[i], var))/(beta[i+1]): delta[i]:=degree(a[i],var)-degree(a[i+1], var): i:=i+1: psi[i+1]:=((-lcoeff(a[i-1],var))^((delta[i-2])))*((psi[i])^((1-delta[i-2]))): beta[i+1]:=-lcoeff(a[i-1],var)*(psi[i+1])^((delta[i-1])): od: print("Last Non-Zero Subresultant: ", sort(simplify(a[i-1])),y): return (Algebraic:-PrimitivePart(a[i-1],var)): end proc

and I get this error:

Error, unable to parse

Would you kindly help me to fix this issue?

Kind Regards,

Ash

 

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