Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

What is happening at f(0)?

Look at PlotProblem.mw

Dear Users,
I hope you are doing well. The following is the code to solve a nonlinear PD equation numerically and I plotted the graphs for T(y,t) sucessfully.

restart; with(plots); PDE1 := Pr*(diff(T(y, t), t)-Ree*(diff(T(y, t), y))) = (1+Nr*(T(y, t)+1)^3)*(diff(T(y, t), y, y))+3*Nr*(T(y, t)+1)^2*(diff(T(y, t), y))^2; ICandBC := {T(1, t) = 1, T(y, 0) = 1, (D[1](T))(0, t) = T(0, t)}; Ree := .1; Pr := 6.2; HA1 := [0, 1, 10]; AA := [red, green, blue, cyan, purple, black];
printlevel := 2; for i to nops(HA1) do Nr := op(i, HA1); print("Nr = ", %); PDE[i] := {PDE1}; pds[i] := pdsolve(PDE[i], ICandBC, numeric, spacestep = 1/200, timestep = 1/100); PlotsT[i] := pds[i]:-plot[display](T(y, t), t = 1, linestyle = "solid", labels = ["y", "u"], color = op(i, AA), numpoints = 800) end do;
display([`$`(PlotsT[j], j = 1 .. nops(HA1))], size = [1000, 600], axes = boxed, labels = [x, (convert("T", symbol))(x, T)], labelfont = ["Times", 14, Bold], labeldirections = [horizontal, vertical], axesfont = ["Arial", 14, Bold], thickness = 3)

I want to plot the graphs for (1+Nr*(T(y, t)+1)^3)*(diff(T(y, t), y)), at t = 1. Also want to plot diff(T(y, t), y) at y = 0 and y = 1 against Nr. Kindly help me in this matter.

Writing an explanatory paragrah i want to use an approximately equal symbol. How can I do this? The palette has lots of symbols but not what in latex would be done with \approx

I just tried to solve a very simple system of equations using solve but depending on how I write the system the command does out give any output. 

restart

solve({I__cm = m*r^2, r*T = I__cm*a/r, g*m-T = m*a}, {T, a})

solve({r*T = m*r^2*a*(1/r), g*m-T = m*a}, {T, a})

{T = (1/2)*m*g, a = (1/2)*g}

(1)

NULL

Solution with pencil and paper

T := (1/2)*m*g = (1/2)*m*gNULL

a := (1/2)*g = (1/2)*gNULL

Check this solution

evalb(g*m-T = m*a)

true

(2)

evalb(r*T = m*r^2*a*(1/r))

true

(3)

NULL


Notice that if I define I__cm then there is no solution being shown. I can rename I__cm to something else like y, still no output. Then in the second system I simply sub I__cm into the equation that has this variable, and it works.

So what's going on here? Why doesn't the first use of solve work?

Download solveSys.mw

How to read the topological structure of chemical from a SMILES file in Maple 

As I want only the physical structure of the molecule

Like in molecular data it gives the bonds of topology {1,2} like the structure it gives

As SMILES can give 2D structure to me 

Kind help how to do 

My following code:

restart;
PDE := diff(u(x, t), t) + u(x, t)*diff(u(x, t), x) - 0.1*diff(diff(u(x, t), x), x) = 0;
IC := u(x, 0) = sin(x);
BC := [u(0, t) = u(2*Pi, t)];
pds := {BC, IC, PDE};
ds := {pds, t = 0 .. 10, x = 0 .. 2*Pi};
p := pdsolve(ds, numeric);
u := rhs(p[1]);
u(x, t);

producing following 2 errors, don't know how to handle?

Error, (in anonymous procedure called from pdsolve/numeric) invalid terms in sum: 0 .. 10
Error, invalid input: rhs received p[1], which is not valid for its 1st argument, expr

How to make this program more effective ?
 

A := [-3, 1, 2];
B := [-2, -1, 1];
C := [0, 3, -3];
                        A := [-3, 1, 2]

                        B := [-2, -1, 1]

                        C := [0, 3, -3]

alpha[1] := 2;#weight
alpha[2] := -1;
alpha[3] := 1;
                         alpha[1] := 2

                         alpha[2] := -1

                         alpha[3] := 1

x[1] := A[1];
x[2] := B[1];
x[3] := C[1];
                           x[1] := -3

                           x[2] := -2

                           x[3] := 0

y[1] := A[2];
y[2] := B[2];
y[3] := C[2];
                           y[1] := 1

                           y[2] := -1

                           y[3] := 3

z[1] := A[3];
z[2] := B[3];
z[3] := C[3];
                           z[1] := 2

                           z[2] := 1

                           z[3] := -3

sum(alpha[i], i = 1 .. 3);
                               2

xG := sum(alpha[i]*x[i], i = 1 .. 3)/sum(alpha[i], i = 1 .. 3);
                            xG := -2

yG := sum(alpha[i]*y[i], i = 1 .. 3)/sum(alpha[i], i = 1 .. 3);
                            yG := 3

zG := sum(alpha[i]*z[i], i = 1 .. 3)/sum(alpha[i], i = 1 .. 3);
                            zG := 0
Thank you.

Is there a way to execute an entire worksheet for a list of values of a parameter.
Sometimes executing in the standard loop can be cumbersome given you have to add catch statements for errors to prevent the loop from stopping.

Hi,

I'm not able to find a way to bring an equation into it's "polynomial" form:

I'd like this expression in the form of:

c1*v^3+c2*v^2+c1*v+c0 = 0

where c1...c4 are my coefficients

How can I do that? 

Hello guys
I'm having trouble converting the RootOf function. Attached is a simple notebook.

Sincerely,

Oliveira

Example.mw

Dear Maple Users:

Could you help in the following question?

How do I use a symbol as a subscript, e.g.  A_*, to label an axis?

Transfer functions are normally not used with units. Involving units when deriving transfer functions can help identify unit inconsistencies and reduce the likelihood of unit conversion errors.

Maple is already a great help in not having to do this manually. However, the final step of simplification still requires manual intervention, as shown in this example.

Given transfer function

H(s) = 60.*Unit('m'*'kg'/('s'^2*'A'))/(.70805*s^2*Unit('kg'^2*'m'^2/('s'^3*'A'^2))+144.*s*Unit('kg'^2*'m'^2/('s'^4*'A'^2))+0.3675e-4*s^3*Unit('kg'^2*'m'^2/('s'^2*'A'^2)))

H(s) = 60.*Units:-Unit(m*kg/(s^2*A))/(.70805*s^2*Units:-Unit(kg^2*m^2/(s^3*A^2))+144.*s*Units:-Unit(kg^2*m^2/(s^4*A^2))+0.3675e-4*s^3*Units:-Unit(kg^2*m^2/(s^2*A^2)))

(1)

Desired output (derived by hand) where the transfer function is separated in a dimensionless expression and a gain that can be attributed to units with a physical meaning in the context of an application (here displacement per voltage).

H(s) = 60.*Unit('m'/'V')/(.70805*s^2*Unit('s'^2)+144.*s*Unit('s')+0.3675e-4*s^3*Unit('s'^3))

H(s) = 60.*Units:-Unit(m/V)/(.70805*s^2*Units:-Unit(s^2)+144.*s*Units:-Unit(s)+0.3675e-4*s^3*Units:-Unit(s^3))

(2)

is(simplify((H(s) = 60.*Units[Unit](m*kg/(s^2*A))/(.70805*s^2*Units[Unit](kg^2*m^2/(s^3*A^2))+144.*s*Units[Unit](kg^2*m^2/(s^4*A^2))+0.3675e-4*s^3*Units[Unit](kg^2*m^2/(s^2*A^2))))-(H(s) = 60.*Units[Unit](m/V)/(.70805*s^2*Units[Unit](s^2)+144.*s*Units[Unit](s)+0.3675e-4*s^3*Units[Unit](s^3)))))

true

(3)

Units to factor out in the denominator are Unit('kg'^2*'m'^2/('s'^5*'A'^2)). Quick check:

Unit('m'*'kg'/('s'^2*'A'))/Unit('kg'^2*'m'^2/('s'^5*'A'^2)) = Unit('m'/'V')

Units:-Unit(m*kg/(s^2*A))/Units:-Unit(kg^2*m^2/(s^5*A^2)) = Units:-Unit(m/V)

(4)

simplify(Units[Unit](m*kg/(s^2*A))/Units[Unit](kg^2*m^2/(s^5*A^2)) = Units[Unit](m/V))

Units:-Unit(s^3*A/(m*kg)) = Units:-Unit(s^3*A/(m*kg))

(5)

"Simplification" attempts with the denominator

denom(rhs(H(s) = 60.*Units[Unit](m*kg/(s^2*A))/(.70805*s^2*Units[Unit](kg^2*m^2/(s^3*A^2))+144.*s*Units[Unit](kg^2*m^2/(s^4*A^2))+0.3675e-4*s^3*Units[Unit](kg^2*m^2/(s^2*A^2)))))

s*(.70805*s*Units:-Unit(kg^2*m^2/(s^3*A^2))+144.*Units:-Unit(kg^2*m^2/(s^4*A^2))+0.3675e-4*s^2*Units:-Unit(kg^2*m^2/(s^2*A^2)))

(6)

collect(s*(.70805*s*Units[Unit](kg^2*m^2/(s^3*A^2))+144.*Units[Unit](kg^2*m^2/(s^4*A^2))+0.3675e-4*s^2*Units[Unit](kg^2*m^2/(s^2*A^2))), Unit('kg'^2*'m'^2/('s'^5*'A'^2)))

s*(.70805*s*Units:-Unit(kg^2*m^2/(s^3*A^2))+144.*Units:-Unit(kg^2*m^2/(s^4*A^2))+0.3675e-4*s^2*Units:-Unit(kg^2*m^2/(s^2*A^2)))

(7)

is not effective because all units are wrapped in Unit commands. Example:

Unit('kg'^2*'m'^2/('s'^2*'A'^2))

Units:-Unit(kg^2*m^2/(s^2*A^2))

(8)

Expand does not expand the argument of Unit commands.

expand(Units[Unit](kg^2*m^2/(s^2*A^2))); lprint(%)

Units:-Unit(kg^2*m^2/(s^2*A^2))

 

Units:-Unit(kg^2*m^2/s^2/A^2)

 

NULL

C1: Expanding Unit command

An expand facility could be a solution that expands a Unit command with combined units to a product of separate Unit commands.

When all units are expanded in a separate Unit command, collect or factor can be used to collect units:

.70805*s*Unit('kg')^2*Unit('m')^2/(Unit('A')^2*Unit('s')^3)+144.*Unit('kg')^2*Unit('m')^2/(Unit('A')^2*Unit('s')^4)+0.3675e-4*s^2*Unit('kg')^2*Unit('m')^2/(Unit('A')^2*Unit('s')^2)

.70805*s*Units:-Unit(kg)^2*Units:-Unit(m)^2/(Units:-Unit(A)^2*Units:-Unit(s)^3)+144.*Units:-Unit(kg)^2*Units:-Unit(m)^2/(Units:-Unit(A)^2*Units:-Unit(s)^4)+0.3675e-4*s^2*Units:-Unit(kg)^2*Units:-Unit(m)^2/(Units:-Unit(A)^2*Units:-Unit(s)^2)

(9)

collect(.70805*s*Units[Unit](kg)^2*Units[Unit](m)^2/(Units[Unit](A)^2*Units[Unit](s)^3)+144.*Units[Unit](kg)^2*Units[Unit](m)^2/(Units[Unit](A)^2*Units[Unit](s)^4)+0.3675e-4*s^2*Units[Unit](kg)^2*Units[Unit](m)^2/(Units[Unit](A)^2*Units[Unit](s)^2), [Unit('A'), Unit('kg'), Unit('m'), Unit('s')])

(.70805*s/Units:-Unit(s)^3+144./Units:-Unit(s)^4+0.3675e-4*s^2/Units:-Unit(s)^2)*Units:-Unit(m)^2*Units:-Unit(kg)^2/Units:-Unit(A)^2

(10)

factor(.70805*s*Units[Unit](kg)^2*Units[Unit](m)^2/(Units[Unit](A)^2*Units[Unit](s)^3)+144.*Units[Unit](kg)^2*Units[Unit](m)^2/(Units[Unit](A)^2*Units[Unit](s)^4)+0.3675e-4*s^2*Units[Unit](kg)^2*Units[Unit](m)^2/(Units[Unit](A)^2*Units[Unit](s)^2))

0.3675e-4*Units:-Unit(kg)^2*Units:-Unit(m)^2*(19266.66666*s*Units:-Unit(s)+3918367.346+.9999999999*s^2*Units:-Unit(s)^2)/(Units:-Unit(A)^2*Units:-Unit(s)^4)

(11)

C2: Using the Natural Units Environment

In this environment, no Unit commands are required and the collection of units should work with Maple commands.
However, for the expressions discussed here, this would lead to a naming conflict with the complex variable s of the transfer function and the unit symbol s for seconds.

NULL

C3: A type declaration or unit assumptions on names

A type declaration as an option of commands like in

Units[TestDimensions](s*(.70805*s*Units[Unit](kg^2*m^2/(s^3*A^2))+144.*Units[Unit](kg^2*m^2/(s^4*A^2))+0.3675e-4*s^2*Units[Unit](kg^2*m^2/(s^2*A^2))), {s::(Unit(1/s))})

true

(12)

could help Maple in simplification tasks (in its general meaning of making expressions shorter or smaller).
Alternatively, assumptions could provide information of which "unit type" a name is

`assuming`([simplify(H(s) = 60.*Units[Unit](m*kg/(s^2*A))/(.70805*s^2*Units[Unit](kg^2*m^2/(s^3*A^2))+144.*s*Units[Unit](kg^2*m^2/(s^4*A^2))+0.3675e-4*s^3*Units[Unit](kg^2*m^2/(s^2*A^2))))], [s::(Unit(1/s))]); `assuming`([combine(H(s) = 60.*Units[Unit](m*kg/(s^2*A))/(.70805*s^2*Units[Unit](kg^2*m^2/(s^3*A^2))+144.*s*Units[Unit](kg^2*m^2/(s^4*A^2))+0.3675e-4*s^3*Units[Unit](kg^2*m^2/(s^2*A^2))), 'units')], [s::(Unit(1/s))])

Error, (in assuming) when calling 'property/ConvertProperty'. Received: 'Units:-Unit(1/s) is an invalid property'

 

On various occasions (beyond transfer functions) I have looked for such a functionality.

 

C4: DynamicSystems Package with units

C4.1: The complex variable s could be attributed to the unit 1/s (i.e. Hertz) either by default or as an option. This could enable using units within the dynamic system package which is not possible in Maple 2022. An example what the package provides currently can be found here: help(applications, amplifiergain)
The phase plot shows that the package is already implicitly assuming that the unit of s is Hertz. A logical extension would be to have magnitude plots with units (e.g. m/V, as in this example).

 

C4.2: A dedicated "gain" command that takes units into account and that could potentially simplify the transfer function to an expression like (2) in SI units. In such a way the transfer function is separated into a dimensionless (but frequency depended) term and a gain term with units.
This would make the transfer of transfer functions to MapleSim easy and avoid unit conversion errors.

 

Download Collecting_and_expanding_units.mw

hi guys,

suppose we have general metric form in 4-D. I want to calculate Covariant derivative of Riemann, Ricci and Weyl tensors.

please help me.

with best,

I dont know why I could not solve this problem.

I have attached my worksheet.

Please anyone help me to get solution to this problem.

Thank you so much

fypppp.mw

DLMF offers different encodings for mathematical expressions. Example:

 

I was wondering if TeX or pMML (never seen before)  can be imported into Maple and subsequently be used as  Maple Input.

First 238 239 240 241 242 243 244 Last Page 240 of 2218