Joe Riel

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15 years, 19 days

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These are answers submitted by Joe Riel

Two approaches

catint1 := proc(a,b)
    parse(cat(a,b));
end proc:

catint2 := proc(a,b)
    10^length(b)*a+b;
end proc:

The second appears to be faster.

Another possibility is to return a record; slots without values can be assigned NULL or whatever you prefer.  An advantage to that approach is that it is frequently much clearer in the code what is being returned.  This is particularly the case when returning more than a few expressions. 

dummy := proc(expr,num)
    coeftayl(expr,x=0,num);
end proc:

Grid:-Set('dummy'):
Grid:-Run(0,dummy,[sin(x),9]);
Grid:-GetLastResult(0);

 

I avoid this problem entirely by using a Makefile to build and install an mla from Maple source files (i.e. ascii text files).  However, I'm not 100% sure that that works on Windows (I use Linux) which has an annoying habit of preventing files (mlas, in this case) from being deleted if in use. 

The help page to which you are referring, ?repository,management, uses, say, $VERSION as a convenient shorthand for the major version of Maple with no implication that such an operating system environment variable has been assigned. On linux the o/s environment variable MAPLE is assigned when Maple is launched, the others not.  To get the install directory for a particular Maple toolbox, do, for example,
 

kernelopts('toolboxdir' = 'MapleSim');
                        "/opt/maple2020/toolbox/MapleSim"
convert(data, listlist);

@nm I misunderstood your question (didn't read it thoroughly).  I thought you wanted to access the value with a getter method and change it with a setter method. What you want is to be able to access it directly, but be able to change it only via a setter method.  Hmm.  You should be able to protect it to accomplish that.
 

foo := module()
option object;
export bar;
export
    ModuleCopy :: static := proc(self :: foo
                                 , proto :: foo
                                )
        protect('self:-bar');
    end proc;

export 
    set :: static := proc(self :: foo, val);
        unprotect('self:-bar');
        self:-bar := val;
        protect('self:-bar');
        val;
    end proc;
    protect('bar');
end module:
(**) foo1 := Object(foo):
(**) foo1:-bar;
                                                             bar

(**) type(foo1:-bar, 'protected');
                                                            true

(**) foo1:-bar := 23;
Error, attempting to assign to `bar` which is protected.  Try declaring `local bar`; see ?protect for details.
(**) set(foo1, 23);
                                                             23

(**) foo1:-bar;
                                                             23

A remember table is not an rtable but a regular Maple table (the "r" in rtable stands for rectangular; rtables are used for Arrays and Array-like structures). Maple tables don't have a last element; that is, there is no way to distinguish the order in which elements were inserted into a table.

If you want the last value computed by a procedure with a remember table, you can assign the computed value, inside the procedure, to a global or module-local, then inspect it when the computation is finished. Note that the last computed value is not necessarily the last returned value; previously computed values may be returned without a computation (that's the point of the remember table).

If you actually want the last returned value, you could wrap the procedure with the remember table insider a larger procedure that calls the one with the remember table and assigns the returned value to a global/module-local.

Assuming you want the last computed value, here is a clever method that avoids using either a module-local or a global. Instead it directly assigns the last computed value to a fixed place in the remember table.

foo := proc(x)
option remember;
local ret;
     # compute value and assign to ret
     foo("last") := ret;
end proc:
foo("last") := "foo was never called": # preassign the last value

To get the last computed value, call foo("last").

Internally 1/(x*y) is represented as, essentially, x^(-1)*y^(-1), so there is no x*y term.

The first column of the spreadsheet defines the values for u, the first row defines the values for v.  You've got the inputs swapped. The y2 port of IBC1 should be connected to the u pin of VLP, the v pin should be connected to the output of the u2 constant block.  With that fixed, the output is as you expect

Yes, Syrup has the equivalent of the SPICE ac circuit analysis; that's probably what it is most useful for. While it does not have the ability to create a circuit via schematic capture, it does include a simple ladder notation that can be used to quickly enter and plot a schematic for a restricted class of circuits.  The latest version of Syrup is available via the Maple Cloud; open the Maple cloud dialog (upper right corner of Maple Standard), go to the public documents and search for Syrup.

The current version can convert its models to modelica, which is the modeling language used by MapleSim.

There are a couple of issues.

The procedure boo is not an export of foo (a procedure, so it has no exports), so calling foo:-boo makes no sense.  Just call boo directly.

For a procedure to access an object's local fields, I believe it has to be a method (local or export) of the object.  The procedure boo is neither (it is local to an export of the object). A workaround is to give it a formal parameter that is passed the value of interest:

module my_class()
option object;
local hint::string:="X"; #private variable to the object

export
    foo :: static:=proc(o::my_class) #can be seen from outside
    local boo; #local proc inside proc foo

        boo := proc(str)
            print("inside boo()");
            print(str);
        end proc;

        print("in foo(), calling local proc boo()");
        print("hint is ",o:-hint); #works OK
        boo(o:-hint);
    end proc;

end module:

o:=Object(my_class);
o:-foo(o);

Another possibility is to promote boo to be be a method of my_class; it can be local.

restart;
module my_class()
option object;
local hint::string:="X"; #private variable to the object
export
    foo :: static:=proc(o::my_class) #can be seen from outside
        print("in foo(), calling local proc boo()");
        print("hint is ",o:-hint); #works OK
        boo(o);
    end proc;
local
    boo :: static := proc(o :: my_class)
        print("inside boo()");
        print(o:-hint);
    end proc;

end module:

o := Object(my_class);
foo(o);

Another solution is to create a method that accesses the field of interest, than call it.

module my_class()
option object;
local hint::string:="X";

export
    foo :: static := proc(o::my_class)
    local boo;

        boo := proc(o)
            print("inside boo()");
            print(o:-GetHint(o));
        end proc;

        print("in foo(), calling local proc boo()");
        print("hint is ", o:-hint); #works OK
        boo(o);
    end proc;
export
    GetHint :: static := proc(o :: my_class)
        o:-hint;
    end proc;
end module:

obj := Object(my_class);
foo(obj);

Another possibility, to avoid reallocating memory, is to use 1-D Array for the original data and then use ArrayTools:-Alias to partition it. For example:

A := Array(1..12, i->i):
B := ArrayTools:-Alias(A, [3,4]):
B[..,3];
                                    [7]
                                    [ ]
                                    [8]
                                    [ ]
                                    [9]

I set up links in ~/bin, which is in my PATH, to point to the installed scripts.  So usually do something like
 

ln -s /opt/maple2020/bin/maple ~/bin/maple
ln -s /opt/maple2020/bin/mint ~/bin/mint

With that, tty maple can be launched using maple on the command line.

If you don't know where maple is installed, but can run it, execute kernelopts(mapledir).

With recent versions of Maple Standard, the current directory is displayed in the status bar (bottom of window).  Click on the display to bring up a directory browser to change the current directory.

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