Whenever I use the function changevar() and press ENTER, I always get the following output, despite paying

attention to the syntax

example:

g1:=changevar(q,g,t);

Output:

g1:=changevar(....)

Ideally, I would like the output to be the following:

g1:=...

What could be the problem with my code?

U

got an error when try to jacobian this

with(VectorCalculus):
f1 := -2*x1-x2; f2 := -x1-4*x2; g1 := 2*x1+3*x2-6; g2 := -x1; g3 := -x2;
penalty := lambda1*max(f1-M,0) + lambda2*max(f2-M,0) + (M^2)*(max(g1,0) + max(g2,0) + max(g3,0)):
obj := eval(penalty,[lambda1=3,lambda2=0.645,M=1]);
Hf := Jacobian(Jacobian(obj, [x1, x2, x3]), [x1, x2, x3]);

Error, invalid input: VectorCalculus:-Jacobian expects its 1st argument, f,
to be of type {Vector(algebraic), list(algebraic)}, but received 3*max(0, -2*x1-x2-1)+.645*max(0, -x1-4*x2-1)+max(0, 2*x1+3*x2-6)+max(0, -x1)+max(0, -x2)

Hello,

       How long can I expect Maple17 to take to algebraically solve a system of 14 nonlinear equations that has approximately 40% nonlinearity in its terms? I am running it on the machine right now, but have no idea what to expect. As mentioned before, I'm new to Maple...

Here is my code:

restart; eq1 := A*z-B*a*z-V*a*q-W*(b+d)*a = 0; eq2 := W*(b+d)*a-V*b*q-(F*G+B+D)*b*z = 0; eq3 := V*a*q-W*c*(b+d)-(B+C+E)*c*z = 0; eq4 := V*b*q+W*(b+d)*c-(B+C+D+F)*d*z = 0; eq5 := G*F*b*z-V*q*e-(B+H)*e*z = 0; eq6 := H*e*z-V*q*f-(B+S)*f*z = 0; eq7 := S*f*z-V*q*g-B*g*z = 0; eq8 := V*q*g+S*s*z-(B+C+E)*h*z = 0; eq9 := F*d*z+V*q*e-(B+C+H+T)*t*z = 0; eq10 := H*t*z+V*q*f-(U+B+C+2*S)*s*z = 0; eq11 := T*t*z-(B+H+Y)*u*z = 0; eq12 := U*s*z-(B+S)*v*z+H*u*z-Y*H*v*z/(H+S) = 0; eq13 := g-c-d-t-s-h = 0; eq14 := z-a-b-c-d-e-f-g-h-s-t-u-v = 0; soln := solve({eq1, eq10, eq11, eq12, eq13, eq14, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, {a, b, c, d, e, f, g, h, q, s, t, u, v, z});

Thanks.

Greetings,

       I am new to Maple and this forum. I would like to obtain a Jacobian of a system of 12 ODEs. What have I done wrongly with my code?

eq_1 := -B*a+A-V*(c+d+t+s+h)*a/(a+b+c+d+e+f+g+h+s+t+u+v)-W*(b+d)*a/(a+b+c+d+e+f+g+h+s+t+u+v);
eq_2 := W*(b+d)*a/(a+b+c+d+e+f+g+h+s+t+u+v)-V*(c+d+t+s+h)*b/(a+b+c+d+e+f+g+h+s+t+u+v)-(F*G+B+D)*b;
eq_3 := V*(c+d+t+s+h)*a/(a+b+c+d+e+f+g+h+s+t+u+v)-W*(b+d)*c/(a+b+c+d+e+f+g+h+s+t+u+v)-(B+E+C)*c;
eq_4 := V*(c+d+t+s+h)*b/(a+b+c+d+e+f+g+h+s+t+u+v)+W*(b+d)*c/(a+b+c+d+e+f+g+h+s+t+u+v)-(B+C+D+F)*d;
eq_5 := G*F*b-V*(c+d+t+s+h)*e/(a+b+c+d+e+f+g+h+s+t+u+v)-(B+H)*e;
eq_6 := H*e-V*(c+d+t+s+h)*f/(a+b+c+d+e+f+g+h+s+t+u+v)-(B+S)*f;
eq_7 := S*f-V*(c+d+t+s+h)*g/(a+b+c+d+e+f+g+h+s+t+u+v)-B*g;
eq_8 := V*(c+d+t+s+h)*g/(a+b+c+d+e+f+g+h+s+t+u+v)+S*s-(B+E+C)*h;
eq_9 := F*d+V*(c+d+t+s+h)*e/(a+b+c+d+e+f+g+h+s+t+u+v)-(B+C+H+T)*t;
eq_10 := H*t+V*(c+d+t+s+h)*f/(a+b+c+d+e+f+g+h+s+t+u+v)-(U+B+C+S+S)*s;
eq_11 := T*t+W*(b+d)*x/(a+b+c+d+e+f+g+h+s+t+u+v)-(B+H+Y)*u;
eq_12 := U*s-(B+S)*v+H*u-Y*H*v/(H+S);
with(linalg);
J := Jacobian([eq_1, eq_2, eq_3, eq_4, eq_5, eq_6, eq_7, eq_8, eq_9, eq_10, eq_11, eq_12], [a, b, c, d, e, f, g, h, s, t, u, v]);

I am getting the message: 

 Vector(4, {(1) = ` 12 x 12 `*Matrix, (2) = `Data Type: `*anything, (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

Thanks!!

I have a rank 1 array M of 1000 values.

I want to apply a function f on each value of M and its location giving,

[f(1,M[1]), f(2,M[2]), ... , f(1000,M[1000])]

is it possible to get this using map or map2 or map[n] or maptype (without using seq since its slowing down computation).

inotherwords can i access the member location inside a map evaluation?

Hey,

I wish to find the zero crossing of the following eq. (with respect to x)

a is typically 1.729, b is 1.139 and c is 0.0688. Ploting the eq. and using the solve command result in two values (zero crossings) when replacing the constants by their respective values, but when I wish to have the solution with respect to the constants a, b and c the result is only for one of them. Any commands that can be helpful in this situation?

Thanks in advance.

Hello,

       I am new to this forum. I have typed the follwing code in Maple17:

restart; eq1 := A-B*a-V*a*q/z-W*(b+d)*a/z = 0; eq2 := W*(b+d)*a/z-V*b*q/z-(F*G+B+D)*b = 0; eq3 := V*a*q/z-W*c(b+d)/z-(B+C+E)*c = 0; eq4 := V*b*q/z+W*(b+d)*c/z-(B+C+D+F)*d = 0; eq5 := G*F*b-V*q*e/z-(B+H)*e = 0; eq6 := H*e-V*q*f/z-(B+S)*f = 0; eq7 := S*f-V*q*g/z-B*g = 0; eq8 := V*q*g/z+S*s-(B+C+E)*h = 0; eq9 := F*d+V*q*e/z-(B+C+H+T)*t = 0; eq10 := H*t+V*q*f/z-(U+B+C+2*S)*s = 0; eq11 := T*t+W*(b+d)*x/z-(B+H+Y)*u = 0; eq12 := U*s-(B+S)*v+H*u-Y*H*v/(H+S) = 0; eq13 := g-c-d-t-s-h = 0; eq14 := z-a-b-c-d-e-f-g-h-s-t-u-v = 0; soln := solve({eq1, eq10, eq11, eq12, eq13, eq14, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, {a, b, c, d, e, f, g, h, q, s, t, u, v, z});

This is to symbolically solve a nonlinear system of (14) equations. But when I press Enter, it just returns the message "Ready". Shouldn't it say "Evaluating"?

I don't see anything syntactically wrong with my code...

Hello there!

There seems to be an issue with indexed variables and the instruction "DGsetup" of the differential geometry package when used with Maple 17. An error is returned to the effect that DGsetup is expecting independent variables to be unassigned names. This phenomenon does not occur with Maple 16!

Here is what I get:

> restart;
> with(DifferentialGeometry); with(Tools); with(Tensor); with(LinearAlgebra);

Executing the following command, I get an error with Maple 17 which does not occur with Maple 16!

> DGsetup([seq(x[i], i = 1 .. 4)], M, verbose);
Error, (in DifferentialGeometry:-DGsetup) expected 1st independent variable to be an unassigned name, received: x[1]

Is there any fix for this problem?

Kind regards
Freddy Baudine

See below for an example. The units in this formula cancel out. Instead I observe this behavior (not just in this case, ALWAYS): The units just keep piling up to an unmanageable pile. That's why I gave up on including units entirely, I end up with 5% (of total screenspace for the entire result) for the numeric part and 95% for the bloated unit result.

How do I get Maple to process the units and not just carry them? I know it can do it, after all, sometimes it does. I just can't see the system.

Why does MapletViewer launch the Maplet Splash Screen and then pop up a box saying it has an error launching the Maplet spash screen? As my previous question stated, it also will not run the maplet, popping up another error box as "explanation".

My maplet runs perfectly correctly and as expected when I run it directly from the worksheet.

However, when I export the worksheet to a .maplet file, it will not run and only gives the error:
At line 135, syntax error: reserved words `quit`, `done`, or `stop` unexpected.

According to wordpad, line 135 of the .maplet file is the last line of both the .maplet file and of the worksheet. It contains the statement:

Maplet[Display](<maplet name>);

There are no `quit`, `done`, or `stop` words anywhere visibly in the worksheet.

What is happening and how do I get the maplet to run?

convert(50, base, 12);

this can change base for integer, however can not change decimal

assume i change decimal to fraction first and then apply convert base to 12 to numer and denom, and divide again to get decimal

it may get a decimal based on base 12

however, how to make this base 12 operation apply in linear algebra calculation

Hi All

Assume that we have:

and the hybrid function with block pulses with the following form:

if we want to introduce this form to maple so that we can do:

then how can we do this????

especially if we want to approximate t or t^2 or sin(3*t) by mentioned form, how maple can help us?

thanks a lot for coming answers 

Mahmood   Dadkhah

Ph.D Candidate

Applied Mathematics Department

if not using

EigenvectorSol := simplify(solve({seq(seq((NewMatrix3 . NewInput3(1..-1,i))[j]=(v[i]* NewInput3(1..-1,i))[j], j=1..3), i=1..3)}, {seq(x||i, i=1..9)}));

and if want to see clearly the steps about how to solve for eignvector, how to do?

because i use solve, it has error

InputMatrix3 := Matrix([[31.25,30.8,30.5],[30.8,30.5,0],[30.5,0,0]]);

NewInput3 := MatrixMatrixMultiply(Transpose(InputMatrix3), InputMatrix3);

FirstEigenValue := solve(Determinant(NewInput3-Matrix([[lambda1, 0, 0], [0, lambda1, 0], [0, 0, lambda1]])), lambda1)[1]; # find back eigenvalue from eigenvector

SecondEigenValue := solve(Determinant(NewInput3-Matrix([[lambda1, 0, 0], [0, lambda1, 0], [0, 0, lambda1]])), lambda1)[2]; # find back eigenvalue from eigenvector

ThirdEigenValue := solve(Determinant(NewInput3-Matrix([[lambda1, 0, 0], [0, lambda1, 0], [0, 0, lambda1]])), lambda1)[3]; # find back eigenvalue from eigenvector

v:=[ FirstEigenValue, SecondEigenValue, ThirdEigenValue];

NewMatrix3 := Matrix([[x1,x2,x3], [x4,x5,x6], [x7,x8,x9]]);

EigenvectorSol := simplify(solve({seq(seq((NewMatrix3 . NewInput3(1..-1,i))[j]=(v[i]* NewInput3(1..-1,i))[j], j=1..3), i=1..3)}, {seq(x||i, i=1..9)}));

EigenvectorT := Matrix([[rhs(EigenvectorSol[1]), rhs(EigenvectorSol[2]), rhs(EigenvectorSol[3])],[ rhs(EigenvectorSol[4]), rhs(EigenvectorSol[5]), rhs(EigenvectorSol[6])],[ rhs(EigenvectorSol[7]), rhs(EigenvectorSol[8]), rhs(EigenvectorSol[9])]]);

Old_Asso_eigenvector := Eigenvectors(MatrixMatrixMultiply(Transpose(InputMatrix3), InputMatrix3));

sys1:=MatrixMatrixMultiply(NewInput3-Matrix([[FirstEigenValue, 0, 0], [0, FirstEigenValue, 0], [0, 0, FirstEigenValue]]),Matrix([[x],[y],[z]]));

sys1a := NewInput3-Matrix([[FirstEigenValue, 0, 0], [0, FirstEigenValue, 0], [0, 0, FirstEigenValue]]);

fsolve({sys1[1][1]=0,sys1[2][1]=0,sys1[3][1]=0}, {x,y,z});

solve([sys1[1][1]=0,sys1[2][1]=0,sys1[3][1]=0], [x,y,z]);

solve([sys1[1]=0,sys1[2]=0,sys1[3]=0], [x,y,z]);

> solve([sys1[1] = 0, sys1[2] = 0, sys1[3] = 0], [x, y, z]);

Error, invalid input: solve expects its 1st argument, eqs, to be of type {`and`, `not`, `or`, algebraic, relation(algebraic), ({set, list})({`and`, `not`, `or`, algebraic, relation(algebraic)})}, but received [(Vector[row](1, {(1) = HFloat(2571.1332294000003)*x+HFloat(1901.9)*y+HFloat(953.125)*z})) = 0, (Vector[row](1, {(1) = HFloat(1901.9)*x+HFloat(1594.5707294000001)*y+HFloat(939.4)*z})) = 0, (Vector[row](1, {(1) = HFloat(953.125)*x+HFloat(939.4)*y+HFloat(645.9307294)*z})) = 0]

v1 := <sys1a[1,1] | sys1a[1,2] | sys1a[1,3]>;

v2 := <sys1a[2,1] | sys1a[2,2] | sys1a[2,3]>;

v3 := <sys1a[3,1] | sys1a[3,2] | sys1a[3,3]>;

v1 := <sys1a[1,1] | sys1a[2,1] | sys1a[3,1]>;

v2 := <sys1a[1,2] | sys1a[2,2] | sys1a[3,2]>;

v3 := <sys1a[1,3] | sys1a[2,3] | sys1a[3,3]>;

eigenvector1 := Basis([v1, v2, v2]);

eliminate({sys1[1][1]=0,sys1[2][1]=0,sys1[3][1]=0},{x,y,z});

eliminate({sys1[1][1]=0,sys1[1][2]=0,sys1[1][3]=0},{x,y,z});

sys1:=MatrixMatrixMultiply(NewInput3-Matrix([[SecondEigenValue, 0, 0], [0, SecondEigenValue, 0], [0, 0, SecondEigenValue]]),Matrix([[x],[y],[z]]));

solve([sys1[1][1]=0,sys1[2][1]=0,sys1[3][1]=0], [x,y,z]);

sys1:=MatrixMatrixMultiply(NewInput3-Matrix([[ThirdEigenValue, 0, 0], [0, ThirdEigenValue, 0], [0, 0, ThirdEigenValue]]),Matrix([[x],[y],[z]]));

solve([sys1[1][1]=0,sys1[2][1]=0,sys1[3][1]=0], [x,y,z]);

Hello,

This is probably a silly question, but I am trying to compare the difference between two variables in the numerical solution of a system of ODEs. Ideally, I would like a method to find the maximal difference that occurs between two variables.

The following is a highly simplified example of what I'm talking about. In this case I'd like some means to find the timepoint and magnitude of the maximal difference between y2(t) and y3(t) for t>0, which from the plot can be seen to occur at about 1.75 seconds. Note: I realise this particular case admits an analytic solution of y3(t) which could be exploited, but in the general case I'm interested in that won't be true.

Thanks in advance for any help you can provide.

Download DsolveSolCompare.mw