How can I add a superscript to a variable, when I try to type it in to the Maxima Computer Algebra System?
So for example, I would like to have variables named U^(AC), U^(DC) where my intention is not to raise the variable to the power of something, but to have it as part of its name.
UPDATE, NEW ANSWER: Code to implement presuperscripts, presubscripts, postsuperscripts, and postsubscripts has been merged into Maxima. It is available now in the current version from Git, and it will be included in the next release of Maxima, which will be Maxima 5.44. See declare_index_properties in the online documentation (via ?).
OLD ANSWER: There isn't a built-in way to achieve that. That said, to some extent you can use A^B as a symbolic variable in some ways, depending on what you are trying to do. For example, given e:X*A^B + Y you can say solve(e, A^B) and it will return [A^B = -Y/X]. If you say more about exactly what you are trying to achieve, I might be able to give more specific advice.
A while ago I wrote some code to enable Maxima to treat indices of variables as subscripts as well as subscripts (as put the indices before as well as after the variable). I will dust off that code and write more about it here.
You can name it like that :
U^"AC"
U^"AC"*2=456; solve(%, U^"AC");
But it is a good idea to 'define' it before with something like :
UAC : U^"AC"; UAC *2=456; solve(%, UAC );
Related
I'm working with Delphi 10.4.
At some places of my code I have to write long identifiers on long statements (e.g. ProductsForSale.fieldByName('quantity').asInteger * ..... / .... etc.). Is there a way to assign a friendly alias (e.g. TheCost) to this piece of code to substitute it everywhere in the application?
I don't want to use a variable or a function to do this. Only text substitution.
No, Delphi (and Pascal) knows
neither aliases (using a different name for a type/variable/function still needs you to define it anew),
nor macros (executing code in the compiler's context is very limited, mostly definings and conditions).
Even if, chances are you'd have to define it bound to a given context/scope: i.e. your favorite alias TooMuchToType might access three variables named one, two and three, but as per scope those variable's types can vary drastically. Its usage would be prone to obfuscated code and a lot of hassle the compiler has to go thru when trying to give you an error message he wants you to understand.
Why not doing exactly that at the end, but in the opposite way? First using a placeholder and when you're done you replace all of them with the actual code. Otherwise this is bascially what functions are there for, if you want it or not.
Problem
I'm writing an essay/documentation about an application. Within this doc there are a lot of code-words which I want to be highlighted using a different font. Currently I work with:
{\fontfamily{cmtt}\selectfont SOME-KEY-WORD}
Which is a bit of work to use every time.
Question
I'm looking for a way to declare a list of words to use a specific font within the text.
I know that I can use the listings package and define morekeywords which will be highlighted within the listings-environment but I need it in the text.
I thought of something like this:
\defineList{\fontfamily{cmtt}}{
SOME-KEY-WORD-1,
SOME-Key-word-2,
...
}
EDIT
I forgot to mention that I already tried something like:
\def\somekeyword{\fontfamily{cmtt}\selectfont some\_key\_word\normalfont}
which is a little bit better then the first attempt but I still need to use \somekeyword in the text.
EDIT 2
I came upon a workaround:
\newcommand{\cmtt}[1]{{\fontfamily{cmtt}\selectfont #1\normalfont}}
It's a little better then EDIT but still not the perfect solution.
Substitution every time a word occurs, without providing any clues to TeX, might be difficult and is beyond my skills (though I'd be interested to see someone come up with a solution).
But why not simply create a macro for each of those words?
\newcommand\somekeyword{\fontfamily{cmtt}\selectfont SOME-KEY-WORD}
Use like this:
Hello, \somekeyword{} is the magic word!
The trailing {} are unfortunately necessary to prevent eating the subsequent whitespace; even the built-in \LaTeX command requires them.
If you have very many of these words and are worried about maintainability, you can even create a macro to create the macros:
\newcommand\declareword[2][]{%
\expandafter\newcommand%
\csname\if\relax#1\relax#2\else#1\fi\endcsname%
{{\fontfamily{cmtt}\selectfont #2}}%
}
\declareword{oneword} % defines \oneword
\declareword{otherword} % defines \otherword
\declareword[urlspy]{urls.py} % defines \urlspy
...
The optional argument indicates the name of the command, in case the word itself contains characters like . which cannot be used in the name of a command.
I should check existence of values based on some conditions.
i.e. i have 3 variables, varA, varB and varC. varC should not be empty only if varA>varB (condition).
i normally use some syntax to check any of the variables and run a frequency of any of them to see if there are errors:
if missing(varC) and (varA>varB) ck_varC=1.
if not(missing(varC)) and not(varA>varB) ck_varC=2.
exe.
fre ck_varC.
exe.
I had some errors when the condition became complex and when in the condition there are missing() or other functions but i could have made a mistake.
do you think there is an easier way of doing this checks?
thanks in advance
EDIT: here an example of what i mean, think at a questionnaire with some routing, you ask age to anyone, if they are between 17 and 44 ask them if they work, if they work ask them how many hours.
i have an excel tool where i put down all variables with all conditions, then it will generate the syntax in the example, all with the same structure for all variables, considering both situations, we have a value that shouldn't be there or we don't have a value that should be there.
is there an easier way of doing that? is this structure always valid no matter what is the condition?
In SPSS, missing values are not numbers. You need to explicitly program those scenarios as well. you got varC covered (partially), but no scenario where varA or varB have missing data is covered.
(As good practice, maybe you should initialize your check variable as sysmis or 0, using syntax):
numeric ck_varC (f1.0).
compute ck_varC=0.
if missing(varC) and (varA>varB) ck_varC=1.
if not(missing(varC)) and not(varA>varB) ck_varC=2.
***additional conditional scenarios go here:.
if missing(varA) or missing(varB) ck_varC=3.
...
fre ck_varC.
By the way - you do not need any of the exe. commands if you are going to run your syntax as a whole.
Later Edit, after the poster updated the question:
Your syntax would be something like this. Note the use of the range function, which is not mandatory, but might be useful for you in the future.
I am also assuming that work is a string variable, so its values need to be referenced using quotation signs.
if missing(age) ck_age=1.
if missing(work) and range(age,17,44) ck_work=1.
if missing(hours) and work="yes" ck_hours=1.
if not (missing (age)) and not(1>0) ck_age=2. /*this will never happen because of the not(1>0).
if not(missing(work)) and (not range(age,17,44)) ck_work=2. /*note that if age is missing, this ck_work won't be set here.
if not(missing(hours)) and (not(work="yes")) ck_hours=2.
EXECUTE.
String variables are case sensitive
There is no missing equivalent in strings; an empty blank string ("") is still a string. not(work="yes") is True when work is blank ("").
I have some proprietary implementation of lua, and all the variables exposed to me are in the form of 'ME.AV123' (for example). What is 'ME'? Is it a namespace? Is it a class? Is there a way to tell? Should I be able to do some sort of type(ME) (which does not seem to work)? In the documentation it says the keyword 'ME' is used to access the objects in the local database.
Follow-up, bonus question - Is there a way to get to all the variables in ME? I.e. - like the global variables use _G[varname], is there an equivalent way to do this for ME?
I apologize if I am not giving you enough. I am new to Lua, and I have relatively limited functionality through this .... thing.
Just to maybe put a finer point on it, and illustrate what I am actually trying to do:
I can interact with some set of variables, which are all in the documentation. All of them are name(addressed?) 'ME.varname'. So, to set 'AV120' to '1', I would say ME.AV120 = 1. I need to set some.. few dozen of these things, and would like a way to loop through all the variables, setting them as I go. I would think something like:
for i,j in pairs(mySettingsTable) do
ME[i] = j
end
Does this make sense?
From the Lua reference manual:
https://www.lua.org/manual/5.3/manual.html#2.1
The language supports this representation by providing a.name as
syntactic sugar for a["name"].
So ME.AV123 is the same as ME["AV123"].
It is just a more convenient form of indexing.
type() returns a string, in case you're wondering why the function does nothing on it's own. print(type(ME)) should work.
I'm working on a large project involving multiple documents typeset in LaTeX. I want to be consistent in my use of symbols, so it might be a nice idea to define a command for every symbol that has a specific meaning throughout the project. Does anyone have any experience with this? Are there issues I should pay attention to?
A little more specific. Say that, throughout the document I would denote something called permability by a script P, would it be an idea to define
\providecommand{\permeability}{\mathscr{P}}
or would this be more like the case "defining a command for $n$"?
A few tips:
Using \providecommand will define that command only if it's not been previously defined. So if you're not getting the results you expected, you may be trying to define a command that's been defined elsewhere.
If you wrap the math in your commands with \ensuremath, it will do the right thing regardless of whether you're in math mode when you issue the command:
\providecommand{\permeability}{\ensuremath{\mathscr{P}}}
Now I can easily use \permeability in text or $\permeability$ in math mode.
Using your own commands allows you to easily change the typographical representation of something later. For instance:
\newcommand{\vect}[1]{\ensuremath{\mathbf{#1}}}
would print \vect{x} as a boldfaced x. If you later decide you prefer arrows above your vectors, you could change the command to:
\newcommand{\vect}[1]{\ensuremath{\vec{#1}}}
I have been doing this for anything that has a specific meaning and is longer than a single symbol, mostly to save typing:
\newcommand{\objId}{\mbox{$\mathit{objId}$}\xspace}
\newcommand{\insOp}[1]{#1\mbox{$^+$}\xspace}
\newcommand{\delOp}[1]{#1\mbox{$^-$}\xspace}
However then I noticed that I stopped making inconsistency errors (objId vs ObjId vs ObjID), so I agree that it is a nice idea.
However I am not sure if it is a good idea in case symbols in the output are, well, single Latin symbols, as in:
\newcommand{\numOfObjs}{$n$}
It is too easy to type a single symbol and forget about it even though a command was defined for it.
EDIT: using your example IMHO it'd be a good idea to define \permeability because it is more than a single P that you have to type in without the command. But it's a close call.