I am maple newbie. Sometimes when I look at Maple code to try to understand the algorithm (which is hard, since I do not know Maple well), I see the code puts ` ` around some keywords. And sometimes it does not. For example, sometimes I see something like (these are random samples) from Maple code shown using showstat()

return `if`(assigned(r),r,{})
r := `union`(r,{solve(op(1,expr) = 1,vs)})
v2 := `intersect`(vs,indets(op(1,expr),'name'));

But sometimes, they do not put ` ` around functions name or keywords, like this:

if nops(v2) = 1 then
t1 := remove(a -> has(a,RootOf),t1);
for t in expr do

and so on.

Can some expert please give what is the rule thumb to use? Should user adopt this method also? When to put ` ` and when not to put ` `?   I understand that ` ` prevents one-time evaluation (or rather, holds off immediate evaluation) and ``  `` prevents two times evaluation and so on. But when to use ` ` is what is confusing me.

Hello,

I was wondering if it is possible to use units in Maple so I can always check if the result I have at the end of calculation is the meter.  For example:

The answer is of course 3.10^8 m^3*kg/s^3

I try to do something with the units but I am unable to crreate something that will simplify the m/s ffactor to 1.

Any idea?

Thank you in advance for your help.

how to convert a nested for loop to iterative version with stack

I'm trying to solve the really simple system u+v = <-2,4> and u-v = <-3,6> for u and v using Maple. My attempt attached.

Download solve_error.mw

Why do I get this error? How might I get the solution?

I have recently been working on a problem using fractional calculus and have come across something in Maple's fracdiff  command that makes no sense to me.

fracdiff(1, x, 1/2) = 0

It should be:     1/(sqrt(x)*sqrt(Pi))

Thanks.

fracdiff.mw

Hi,

I have produced a large Matrix by first using dsolve and then plotted it using odeplot (see below). My question is, how to I export this matrix ( 2599 x 2) to an ascii file? I have been googling around, but haven't found a solution for my matrix (have seen that it works if I just make a simple matrix and then export it). I apologize if someone find this question simple, not very experienced in Maple.

Thanks in advance.

diffsol := dsolve(subs(parametertotal,diffsystem) union subs(parametertotal,initialCondition),numeric,method=rosenbrock_dae,range=0..t_fin);
proc(x_rosenbrock_dae)  ...  end;

     

P1 := odeplot(diffsol,eval([E[init]+nu*t,jteny],parametertotal),0..t_fin,view=[0.8..1.6,0..0.004],refine=2);

plottools[getdata](P1);

["curve", [.500000000000000000 .. 1.60000000000000009, 1.51870824668638962*10^(-8) .. 0.279325471225829770e-2], Vector[column](4, [` 2599 x 2 `*Matrix, `Data Type: `*float[8], `Storage: `*rectangular, `Order: `*C_order])]

I solved this (aq1) equation and got a set of answers, but when I want to solve another equation (aq) that is like (aq1)  it took a long time and I stopped progressing.

aq1 := -6.801867*10^(-32)*omega^16+(2.20054799*10^(-46)*I)*omega^23+(6.14329398*10^(-52)*I)*omega^25+(1.*10^(-11)*I)*omega^3+(2.*10^(-14)*I)*omega^5+(9.*10^(-10)*I)*omega+(2.*10^(-25)*I)*omega^11+5.95367451*10^(-12)*omega^8-2.10490578*10^(-16)*omega^10+3.6487095*10^(-21)*omega^12-3.4507372*10^(-26)*omega^14-4.53641375*10^(-54)*omega^26-1.844174702*10^(-48)*omega^24-.2318547310*omega^2+0.2767383695e-3*omega^4+15.23320543-2.607001427*10^(-43)*omega^22-1.252442537*10^(-38)*omega^20-1.58024603*10^(-34)*omega^18-(4.8*10^(-28)*I)*omega^13+(2.68604*10^(-29)*I)*omega^15+(1.4639509*10^(-32)*I)*omega^17+(1.21776770*10^(-36)*I)*omega^19+(2.77270182*10^(-41)*I)*omega^21-7.070170160*10^(-8)*omega^6

sd1 := solve(aq1)

aq := (2.626145*10^(-111)*I)*beta^41+(2.723460372*10^(-55)*I)*beta^25-1.125718*10^(-103)*beta^38-4.42696*10^(-96)*beta^36+(4.038976*10^(-119)*I)*beta^43+(1.897840*10^(-135)*I)*beta^47-1.4537*10^(-128)*beta^44-2.393897*10^(-75)*beta^30-5.345113*10^(-69)*beta^28-(8.88232*10^(-14)*I)*beta^7+(3.78162*10^(-127)*I)*beta^45+(1.87236321*10^(-39)*I)*beta^19-4.22943*10^(-111)*beta^40-5.98764*10^(-82)*beta^32+(1.73215*10^(-27)*I)*beta^13+(3.14576*10^(-144)*I)*beta^49+1.0000002*10^(-150)*beta^50+1.000483*10^(-142)*beta^48+(0.5707492e-4*I)*beta-1.860356732*10^(-56)*beta^26-1.202764308*10^(-50)*beta^24+0.1078870970e-3*beta^4-.1337634356*beta^2+(4.558807*10^(-82)*I)*beta^33+11.99907662+(1.552482870*10^(-49)*I)*beta^23+1.50289073*10^(-33)*beta^16+(4.738072*10^(-89)*I)*beta^35-2.560992731*10^(-45)*beta^22-1.821396189*10^(-40)*beta^20+1.*10^(-159)*beta^52-1.025045*10^(-118)*beta^42-2.708307310*10^(-27)*beta^14-2.880*10^(-137)*beta^46+3.616579272*10^(-22)*beta^12-2.775313578*10^(-17)*beta^10+(2.247453*10^(-75)*I)*beta^31+(4.317773*10^(-69)*I)*beta^29-(8.4742656*10^(-63)*I)*beta^27+(1.086756*10^(-103)*I)*beta^39+(2.875650*10^(-96)*I)*beta^37+(2.927689932*10^(-44)*I)*beta^21+(5.19084*10^(-18)*I)*beta^9+(3.3203077*10^(-35)*I)*beta^17-1.867365177*10^(-8)*beta^6+1.091287414*10^(-12)*beta^8-3.549248092*10^(-36)*beta^18-6.89128*10^(-89)*beta^34-(1.32011*10^(-22)*I)*beta^11+(8.67973*10^(-32)*I)*beta^15+(5.131768*10^(-10)*I)*beta^5-(6.362604*10^(-7)*I)*beta^3-(5.75387*10^(-153)*I)*beta^51

How can I solve (aq) ?

The writings in the variables palettes are overlapped. Is there any solution suggestion?

any one managed to get this cloud app to work? I get an error on simple inputs:

http://maplecloud.maplesoft.com/application.jsp?appId=5651983367143424

I have to say also that the design of these apps is not well thought. The UI is too large to fit on the screen. Also, there is no button for the user to click on once input is there telling it to "proceed" It is not user friendly UI design.  I could not figure how to make the app full screen, instead of having it one window inside another for example.

The first half of this work sheet deals with SHM of pendulum. In the second half of the work sheet I attempt to solve for the general case of a swinging pendulum. Maple introduces a place holder (correct me if I have used the incorrect termonology) " __a" which I do not understand. What variable(s) should I replace it with and is there an automatic way of doing so?
 

Download SHM_and_not_so_SHM.mw

Hi,

I want to subtract two functions. One of them is numeric-type and the second is exact. Something like this:

solNum := dsolve(Dsys, numeric);

sol := dsolve(Dsys);

plot(solNum-sol)

In the last step there is an error (of course). How can I fix it?

Thank you very much

The following procedure is intended to recursively generate all vectors in the set of n dimension vectors with elements 0 to p-1. If I use a fixed value for p it works fine, but as soon as I introduced p as an argument it gives the error "Error, (in F) invalid input: F uses a 2nd argument, n, which is missing".

F:=proc(p,n)
  if n=1 then:
    return [seq(Vector([x]),x=0..(p-1))];
  else:
    return [ seq(seq(Vector([v[],xn]),v in F(n-1)),xn=0..(p-1)) ];
  end if:
end proc:

F(3,2);

I cannot for the life of me figure out what is wrong with the above code? Can anyone enlighten me?

Thanks in advance for your help.

Hi All,

I have problem how to formulate optimization problem with additional parameters.
For example let objective function is as follow:

ObjF:=proc(x,Delta)
    return sin(x) + cos(x) + Delta;
end proc;

In Matlab we can formulate the following optimization problem:

Delta = 10;
f=@(x)ObjF(x,Delta);
options = optimset('Algorithm','interior-point');
x = fmincon(f,0.1,[1;2],[],[],[],[],[],[],options);

where:

function y = ObjF(x,Delta)
    y = sin(x) + cos(x) + Delta;
end

In above example I can pass additional parameters (Delta) to objective function an then I can start optimization
to find solution. How to define above problem in Maple ? How to pass additional  parameters  befor we starat the optymalization?

Best,

Rariusz

I have a function that is defined by a proc command including some conditional statements (if ... then ...). The conditions are so long so that I can not use a piecewise function instead of using proc. The commands in my code are long and I simplify my question as follows:
f := proc(x) local r; r := sin(x)+x*cos(x); if abs(r) < 1/2 then sin(x) else cos(x) end if; end proc;

plot('f'(x), x = -1 .. 1) works fine but the command int(('f')(x), x = -1 .. 1) gives an error:
Error, (in f) cannot determine if this expression is true or false: abs(sin(x)+x*cos(x)) < 1/2

Is there any way (except rewriting the function as a piecewise function) to get rid of the error? 

Any help is appreciated.

#my testing for wildcard to one
#after testing, it loop a very long time and not stop
ppp := [[0,0,0,x],[0,0,1,0],[0,1,0,0],[1,0,0,0]]:
check1 := [seq(0,ii=1..nops(ppp))];
ttt1 := [[0,0,0,1],[0,0,1,0],[0,1,0,0],[1,0,0,0]]:
mmmeaght1 := [seq(0,ii=1..nops(ppp[1]))]:
bbb1 := [seq(0,ii=1..nops(ppp[1]))]:
emap := [(xx) -> if [xx < 0 assuming x > 0] then 0 else 1 end if, (xx) -> evalf(1/(1+exp(xx)))]:
#trace(perceptronrule1);
MM(ppp, ttt1, mmmeaght1, bbb1, check1, emap);
 

when test wildcard variable for input, would like to assume x > 0 then

i try assuming x > 0 , got error