Maple Questions and Posts

These are Posts and Questions associated with the product, Maple
When doing an implicit plot recently, I ended up with a whole large triangle which was completely tessellated with much smaller triangles. The checking of other graphs and numerical data of the function in this region, it was very clear that the implicit function should be a well defined line in this region. Further look at the code for implicitplot() indicated that, after some setup work, it ultimately called exactly the same routine (`plot/iplot2d`()) as plots[contourplot]() with the option "contours=[0]" to do the actual calculations. I then discovered that when I called contourplot() directly with the "contours=[0]" option I got a correct implicit curve consistent with my other data and with no tessellations.
As currently programmed, fsolve() does not do numerical derivatives for systems of equations. The reason for this is that subs() is used instead of eval() when evaluating derivatives. [Note: jacob is the symbolically defined jacobian of the system of equations and lsub is the sequence of appropriate numerical substitutions (not the "list" of substitutions the mnemonic might suggest).] The original statement (in `fsolve/sysnewton`) is: A:=traperror(evalf(subs(lsub,jacob),Digits-5+n)); The functions evalf() and subs() apparently do no know how to work together to produce numerical derivatives. However, the following statement does work.
Maple displays a defined procedure (yours or Maple's)as output when you enter definition or when you execute eval(). It should be noticed that in either case, Maple uses its own well defined indention scheme, regardless of what indention scheme you used or didn't use when you input the procedure. Now if you want to edit the procedure, and your only copy is gotten by copying Maple's output to an input line, you will have to deal with Maple's hidden indention characters at the beginning of each line. I have been unable to find any Help material on this, and, in particular, I have not been able to find any way to edit (delete or input) these characters directly. However, they are all invisibly located in the blank space, which is visible, at the start of each indented line. The code seems to be of the form "indent a fixed number of spaces more than the previous line". These fixed numbers are one of three values, a positive number (approx. 3), 0, or a negative number (approx. -3).
As most of you have probably experienced, even Maple 10.4 in standard 2D Maple input has some strange editing behavior. Most of it is of the variety of "What you see is Not what you get". There are two basic kinds of things that can happen: (a)You get strange errors that seem impossible from the code that you can see, such as "missing operation" or "object used as name" or even "non-matching delimiters"; and (2) Your editing action happens much further away or much more extensively than your cursor position or highlighting would indicate. This apparently happens because Maple is creating a parsing structure on the fly behind what you are editing and not visible to you. When some incomprehensible errors happen or Maple seemingly does not want to allow you to edit what you see is wrong, sometimes the only remedy is to retype whole blocks of code (possibly creating other errors in the process requiring the same cure, etc., etc.). Till Maple can supply us with a structural viewer that would allow us to easily find and correct such problems, I want to pass along some tips I have learned in my frustration.
I kept seeing in the help pages for linalg that it is being superseded by LinearAlgebra, so I have tried to work with LinearAlgebra. However, it turns out that LinearAlgebra is very clumsy and annoying for symbolic computations. LinearAlgebra was clearly meant to be a numerical calculation package. Unfortunately, the desiderata for numerical calculations are not the same as for symbolic calculations. The main feature of LinearAlgebra which causes this clumsiness is the requirement that all elements of a Matrix be defined. To do symbolic calculations this means assigning a symbol to use with an index for the undefined elements of the Matrix. The name of this symbol has to be different from that of the Matrix itself, and the indexed symbol is not an array or a table or a Matrix. Already then you have two names for essentially the same thing. ==> First Problem. Now, lets say you do some calculations with these Matrices and end up with expressions that that contain the indexed symbolic names. To assign other values to these indexed symbolic names in the resulting expressions, you have to assign the indexed symbolic names new values and you cannot use matrix operations for that since these indexed symbolic names are not arrays or Matrices or even tables. ==> Second Problem. Now if you want to unassign the symbolic names again or assign new values and have these values show up in the original Matrices, you have to reassign the symbolic names and reassign the values in the original Matrices. (Matrix elements cannot be unassigned.) In other words, do the job twice. ==> Third Problem.
There is a general problem which arises when one uses assume() that can be quite confusing. I seems that once an x~ is passed on by assigning a data structure containing it to another name, it becomes an entity on its own, a sort of vintage x~, with no connection back to the original variable on which the assumptions were made. It has no unique name and no way to access it for manipulation or redefinition. The code x:='x' does not affect these vintage x~'s. Even the function addionally() does not affect these vintage x~'s. Thus one can have a whole set of x~'s of different vintage in one's data structures with no way to tell them apart or manipulate them. This has tied some of my codes in knots before I realized what was happening. It would be so much less frustrating if each new vintage received a unique name that could be referenced by the user.
I have seen a number of forum questions concerning showing students the steps in a problem. There seems to be some confusion about how to do this reliabley and easily. A method I have found useful is seen below:
I have Maple worksheets a.mws and b.mws in directory C:\maplecode. I’ve set this directory to be the current directory by executing the command currentdir(“C:\\maplecode
Hi, I have a proc that generates a "piston" plot in 2-D. I generate this with a procedure. Calling the procedure works, but calling it from Plot3d doesn't. I'm really not sure why. I'd appreciate the help. My stuff is below: Diameter := 46; Shape := proc (x,y) if((x^2+y^2)^(0.5) <>
hello, i just started using maple in school and i was wondering if i can make it show all calculations. it always gives a nice answer but im wondering it if can show me all step by step and not just the answer so it will help me learning. thanks in advance.

btw i tried looking in the manual and using google, but didnt find anything.

jenni
I have an expression of the form diff(var_name(t),t)= -K + procedure_name(var_name(t)) where K is a constant. The procedure is a boolean function. the var_name(t) is not recognised as a numerical value in the procedure and an error is reported. Any suggestions greatly recieved. The actual procedure is shown below. > restart: > m:=1: > P:=10: > RLLS:=proc(vt) > local max,v,N,k,feq,mu,lambda; > max:=.01: > v:=vt: > N:=9.807: > k:=.0001: > feq:=10: > mu:=2: > if abs(feq/mu*N)
Hi all. Is it possible to construct a generic polynom of degree n with generic coefficients a1 a2 .. an ? I would like to be able to write things like Sum(a_i X^i, i=1..n) in all generality. How to specify the coefficients (lists, arrays .. what ? ) ? Afterwards, the goal would be to be able to get the numerator and denominator of a sum of rational fractions indexed somehow by i plus a set of very generic coefficients a_i. Any hint of how to do this kind of manipulation is most welcome, even in the simple case where we are given the value of n from the beginning. Thank you for your attention.
I wish to extract the coefficients associated with a particular variable. I have assigned the results of a symbolic solve of a system of equations (sol) using assign(sol): One of the assigned variables in (sol) is ROLL and the symbolic solution is of the form ROLL; 200*a*b^2*VAR1 + 3000*b*VAR2 + 1500*cos(c)*d*VAR1 . . . (the actual expression is hundreds of line long and each VAR is randomly distributed in the expression) How do I isolate the coefficients associated with a specific VAR eg for VAR1 I want to be able to make the assignment coefVAR1:=(200*a*b^2)+(1500*cos(c)*d)
I use to own a old Maple version 8.0 since the RedHat 6.0 days. I have been able to make it run till FC3 (with export LD_ASSUME_KERNEL=2.4.1 and with a new JRE). However, recently, I upgraded the system to FC5 (kernel 2.6.15) from FC3 (I did not try FC4) and Maple stopped working. I've used the "export LD_ASSUME_KERNEL=2.4.1". The error I get is : $ /opt/Maple8.0/bin/maple /bin/sh: error while loading shared libraries: libdl.so.2: cannot open shared object file: No such file or directory /opt/Maple8.0/bin/maple: line 162: /opt/Maple8.0//cmaple: No such file or directory A ldd on libdl.so.2 gives
Hi, I've been trying to label the columns of a column graph I created using the ColumnGraph command. But I just can't figure out how to do it. Any tips?
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