Mac Dude

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MaplePrimes Activity


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@Carl Love Carl, while I agree with your notation being the correct one, my (sloppy) notation is in good company: Maple's own Help facility lists constructs like sin@@0, sin@@1 without the argument (see Help on @).  Needless to say, the argument is needed when you actually want to do something with the function.

M.D.

Not so clear about the f^4 part; but if f(x,y)=(x,y) then f(x,y) applied 4 times (which is how you define f^4 in your question) will also be (x,y). Then Maple can find a solution rather easily:

solve([x=f(x,y)[1],y=f(x,y)[2]],[x,y]);

Needless to say; f^4(x,y) might have other fixed points that are overlooked by this approach.

Mac Dude

fixed_point.mw

Edit: It turns out that another pair of fixed points exists for f(f(x,y)) that the above overlooked. These will be fixed points for f@@4 as well. But f@@4 is a polynomial of 15th order in x & y, and no general solution exists.

fixed_point_2.mw

@Thomas Richard I finally got around to downloading this to an old-ish iPad running iOS 9.3.5 or so (last one it can run). App downloads and starts up, but then dies without ever showing more than the splash screen. Repeatedly.

So, iOS 9 does not seem to be supported. Excuse the question, but did this app get tested on the different iOS versions?

Mac Dude.

 

In my experience getting this error almost always indicates a programming error (on my side).

Upload file! Big Green Up-Arrow!

Mac Dude

@acer I think you are right, except I would then have looked for a convert(xpr,string) construct, which as a matter of fact does exist. And convert can also do hex (as can sprintf).

The key take-away for me is the custom tickmarks definition. I knew I could use it to make tics in units of Pi, e.g., but using it with a list is new to me.

So, thanks both again,

M.D.

@acer , @Christian Wolinski  Thanks both very much. I think both your methods will work, but acer's wins on simplicity.

Mac Dude

This looks like it could be useful.

Where can I learn which OS versions are required?

Mac Dude

@Daniel Skoog Daniel, thanks much. Do sign me up as one more person interested in this.

M.D.

 

@acer Thanks. I guess that means that the GUI is somehow interfering with the parameters of ssystem().

Odd, but using the cli is not a real option for me; my stuff is all done in worksheets.

:-(

M.D.

Can you give more context? Your procs foo and boo each return a record with some entries. For this particular example, I would have one procedure only that has all the record elements as parameters so that you can say

foo(name,age,whatever);

and have it return the record.  foo() becomes a constructor of sorts.  If you assign all records to some data structure (array, table, whathaveyou) then you can build up a collection of records you can act on, e.g., by iterating over the indices. It is not unlike what tomleslie wrote.

But I may e missing something here.

M.D.

 

@acer Ok so I was able to get a script to work. Haven't exhaustively tested arguments yet, but a simple one was echoed back successfully. I also realized I was in error about the default directory: trying this again I get a directory deep in the bowels of the Maple installation. So absolute path is required. Within the script I can cd.

But I cannot get compound statements to work, like ssystem("(pwd ; ls)"). Any reason why these don't work?

Thanks,

M.D.

@Mac Dude Ok, so now it works.

Filters_test.mw

@acer Ah, now I get it. Upon execution this file sets up the environment and passes along anything that Maple spits out, to e.g. run python in its own process. Had not thought about that but definitely will pursue.

Thanks,

M.D.

@acer Yes, I certainly could write a script file and then run that. That would be likely a two-stage approach: first write the script, then execute it. Quite possible assuming something like cat can be made to work (cat in the shell, that is). Writing a script and passing arguments is a bit more tricky as the argument maybe a whole routine. I was thinking of shortcutting the process by using the -c flag in python to just upload the script into the command line. The general idea is to submit a piece of code to a python script and read the result back in to Maple. And for python you can read python, perl, Ruby, what have you. I was even thinking about a Fortran program, but the overhead and vagaries of compiling and linking likely makes that approach impractical. All of this stuff is numerical, but Maple would generate the program, puts it into a string that goes into the ssystem() call.

Specifically for Python I need numpy and maybe scipy; right now I am not able to import these through ssystem(). I assume the reason is that the environment is not being setup.

I did not use absolute paths for .cshrc because ssystem("pwd") tells me that my home directory is the default for ssystem() calls. I'll try absolute paths. ssystem("printenv") tells me that ssystem() is running tcsh (which is my default shell), but clearly my .cshrc is not being run and any attempt to setenv something through ssystem() also fails (e.g. ssystem("setenv PATH /opt/local/bin:$PATH") fails). It is a bit difficult to trouble shoot all this as I cannot concatenate any shell commands (e.g. ssystem("cd work ; ls") does not work even though it works perfectly well in the interactive shell) so I cannot print the output, and ssystem() just returns an error code (usually 1) and an empty string.

Right now my tests use direct strings just the way I type them here. I did experiment with quoting e.g. the string in a composite statement (ssystem("'pwd ; ls'")) but to no avail. Interestingly enough composite statements do work when I send them to python using -c (e.g. ssystem("python -c A=2;print(A)") works (returns (0,"2"); ssystem("pwd ; ls") does not work (returns (1,"")) ).

Thanks,

M.D.

 

 

@fatemeh1090 I looked at the LaTeX output and it looks sensible to me (I didn't try to typeset it since I don't have a LaTeX doc handy I could paste it into). The expression fills two pages on my screen, so the LaTeX output expression is relatively large (potentially leading to memory problems). 

I don't have my copy of MathType on this computer so that has to wait until tomorrow. I also see that Maple 2015 on this computer may be less powerful w.r.t. outputting expressions in different formats than the newr versions. I do have to say that I have never attempted to put such a large expression into any document; the size alone may cause problems even if we find a way to get it into MSWord.

Stay tuned, but be patient.

M.D.

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