Questions tagged [upvalues]
The upvalues tag has no usage guidance.
77 questions
2
votes
1
answer
81
views
Why can't I assign upvalues to NonCommutativeMultiply?
I'm trying to define a non-commutative product with respect to which, certain quantities (e.g. numbers, and some other quantities defined in my code) behave as "scalars" and can be pulled ...
- 461
3
votes
1
answer
155
views
Pattern matching vs. condition in a function
I'm trying to learn stuff from pattern matching but I found sometimes pattern matching does not work as I expected. Could anyone explain why the below outputs are not same? Thank you.
And could anyone ...
- 31
3
votes
3
answers
108
views
Can't get TagSetDelayed to match LHS when the latter has a Hold attribute set
I'm following this example here;
Code Readability and Object-Oriented Code
...
- 790
4
votes
1
answer
101
views
Can UpValues (as well as other "*Values") always be converted to DownValues?
As this post has discussed, UpValues are certainly useful, and as this post has discussed, g /: f[g[x_]] := h[x] is not ...
- 567
1
vote
0
answers
58
views
Overloading the Normal function
I am currently working on library that keeps functions in unevaluated form, e.g.
In: a = RhoVariable[s]
Out: RhoVariable[s]
RhoVariable has some definition, namely ...
- 84
1
vote
1
answer
54
views
How to clear a selection of definitions from UpValues?
I'm trying to set up a bunch of 2D points using UpSet that I am going to use later for building lines and graphs.
...
- 342
17
votes
1
answer
467
views
Broken ValueQ function in Mma12.2?
f[x] ^= 1;
ValueQ[g[x]]
returns True in Mathematica 12.2. Is it a bug?
- 926
1
vote
1
answer
85
views
Define a function for symbols with UpValues
Suppose that we define UpValues for different symbols
isSpecialFunction[N1]^=True
isSpecialFunction[N2]^=True
isSpecialFunction[N3]^=True
I would like to make the ...
- 1,688
5
votes
1
answer
34
views
How to duplicate UpValue of one function to another?
Let's say I have defined a function zO for the following up-values
...
- 1,473
3
votes
0
answers
77
views
What are some ways to overload Min in order for it to work with user defined expressions?
I have defined size to work with discrete size labels:
...
3
votes
1
answer
151
views
General definitions of deeply nested functions without SetDelayed, "UpUpValues"
I'd like to assign an "UpUpValue" in a way generalized to any nested head surrounding the value for which the UpUpValue would be defined. That is, if a function ...
- 1,177
4
votes
2
answers
330
views
How to set a rule that's too deep for UpValue?
I want to automatically transform Conjugate[a CenterDot[x, y, z]] to Conjugate[a] Conjugate[CenterDot[x, y, z]]. However, the ...
- 685
0
votes
1
answer
59
views
Modified "Plus" function: how to save just the final result of an addition of multiple objects?
In my version of object-oriented programming in Mathematica, essentially (without going into details) obj[a] is a reference to an object whose actual data is stored ...
user73765
5
votes
2
answers
283
views
Efficiency of the rule _ * 0 := 0
In the standard evaluation process, innermost parts are evaluated first. For example:
In[0]:= (a/a + 1) * 0
The evaluation process gives:
...
- 51
3
votes
1
answer
86
views
Upvalues of modified system functions
Suppose that someone (e.g. the author of a package I need to use) modifies
the upvalues of a system function in the following way
...
- 3,572
1
vote
1
answer
121
views
How to use an up-value assignment when all symbols are "too deep"?
I would like to make an up-value assignment such as
a/:Conjugate[a[x]]a[x]+Conjugate[b[x]]b[x] = 1
or
...
- 12.1k
5
votes
2
answers
174
views
How to prevent arguments UpValues from being used in selective functions
Ok, I know the simple answer is to set some form of Hold attribute to the function but bear with me for a bit while I explain my motivation and why that is not quite what I want.
I have a collection ...
- 352
1
vote
0
answers
205
views
Understanding TagSetDelayed
I was reading What is the distinction between DownValues, UpValues, SubValues, and OwnValues? and I started to be confused with the part "Upvalues" of the first answer.
Some of my confusion comes ...
- 2,184
8
votes
2
answers
295
views
Overloading functions like Mean for distributions
I'd like to understand how functions like Mean are overloaded to provide the right behavior for the distributions in Mathematica (like NormalDistribution or PoissonDistribution).
I originally assumed ...
- 482
1
vote
0
answers
38
views
Holding evaluation of flat, orderless, function in up value [closed]
I have an operator that is flat and orderless that I want to evaluate only after the expression has been entirely flattened. Essentially, I want an expression of the form ...
- 11
8
votes
2
answers
242
views
Issue with Upvalues
I want to introduce two variables (I call them EXt and EXtC, where "C" stands for complex conjugate) which would mimic the behavior of a phase of a complex number. For that, I use the following tags:
...
- 245
7
votes
2
answers
271
views
What makes a pattern more general?
This is a rewording of the question. The original post is below.
How come that a pattern for an expression with a specific head is not more specific than a pattern for an expression with a generic ...
- 6,458
9
votes
0
answers
126
views
List assigment ({...}={...}) and UpValues
Let's say I want to track any assignment attempt for a variable a:
a /: Set[a, x_] := Print@{a, x}
This works as intended:
<...
- 34.4k
5
votes
1
answer
129
views
? vs Information - Making UpValues less destructive
I'll first state the main question of this, what follows afterwards are some of my thoughts/attempts at fixing it and additional questions about possible improvements (getting an answer to those would ...
- 34.4k
8
votes
1
answer
118
views
TagSet for symbol inside NumericQ behaves differently than in other fooQ functions
I am trying to define some symbols as being numeric by using TagSet and encountered the following different behaviors between NumericQ and e.g. ...
- 235
2
votes
0
answers
210
views
What is the correct usage of HoldFirst?
I encountered a situation where using HoldFirst seems to do the trick for the specific task, but I am uncertain about the proper use of this attribute.
Consider ...
- 4,225
0
votes
0
answers
64
views
Defining UpValue like replacements confined to exprs with specific Head
I'm not seeing a clean method to redefine builtin functions like Cross, Dot, etc. in such a way they only are only applied to expressions that are using some marker-like Head value. Reduced example, ...
- 141
3
votes
3
answers
663
views
Define derivatives of symbols
I have a symbol a appearing in my computations, which has a complicated definition in terms of other variables. However, I know that any derivative of ...
- 951
1
vote
1
answer
98
views
How to find all up-value symbols related its object
Suppose I set a series up-value for a rectangle like:
rectangle[long] ^= 10;
rectangle[width] ^= 12;
rectangle[height] ^= 28;
How to find all of the symbol about ...
- 27.2k
1
vote
0
answers
77
views
How to update a Text Field Widget during evaluation of a function
My problem is rather simple, I need that the TextField widget named Sumfield updates its value during a function evaluation, in ...
- 11
2
votes
1
answer
386
views
Tag protected error for Grad despite using Unprotect[Grad]? [duplicate]
I've defined an upvalue grade[k,m], where k is an integer and m is a matrix, and have defined a number of overrides for this type in the normal Mathematica namespace (...
- 6,488
1
vote
0
answers
74
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Another question on using UpValues with Derivatives
I want to create an UpValue that will cause a function that is zero for it's second derivative to have a value when the second derivative is integrated. The ...
- 43
0
votes
1
answer
77
views
Trying to "fix" Simplify, but cannot Up/DownValue it because it is Protected
There is an irksome shortcoming for Simplify that I encountered:
Simplify not evaluating completely with Square roots
-- still not entirely sure if it's because of AssumptionsMaxNonlinearVariables ...
- 283
4
votes
1
answer
577
views
Simplify not evaluating completely with Square roots
Here's a simple question. It's no longer high priority that I know this, but it's something that can come in handy later on.
...
- 283
1
vote
1
answer
197
views
Is there a better way to overload Plus?
I'm writing a function to produce a more readable version of output which consists mainly of Plus[seq__] where seq__ matches-for ...
- 4,225
14
votes
1
answer
628
views
How to define homogeneous functions that respect Euler's theorem of homogeneous functions?
A homogeneous function of degree $k$ is defined as a function that observes the following specification rule:
$f(a x_1, a x_2, ..., a x_n) = a^k f(x_1, x_2, ..., x_n)$
(see Wikipedia entry, ...
- 4,225
5
votes
2
answers
121
views
Local modification of built-in command via UpValue
I have a computationally intense function f that returns a matrix. Sometimes only the diagonal is needed, which is faster to compute, thus there's a syntax for f to ...
- 777
1
vote
0
answers
1k
views
Setting derivative of function equal to 0 at x=0 using UpValues
I'm trying to set the derivative of a function to zero at a specified point. This will act as an initial condition for an algorithm I'm writing: so I'm specifying the value of the function at x=0, and ...
- 581
4
votes
1
answer
151
views
Upvalues for Missing do not work with Dataset
Consider the following Dataset:
d = Dataset[<| 1 -> Missing[], 2 -> 1.0, 3 -> 4.0 |>]
And the following Upvalue for Missing:
...
- 979
3
votes
1
answer
86
views
Custom iterable objects
I understand that to create objects with custom behavior with respect to existing code one uses upvalues. However, I'm at loss when it comes to guess what interface is expected from objects fed to ...
- 1,617
11
votes
4
answers
378
views
How to prevent Quantity calculations from converting units
I have an accrual calculation that I would like to preserve the units even though they are of the same dimension (e.g. time). For example, I would like the following
...
- 43.2k
10
votes
1
answer
291
views
How to deal with bad arguments when a function's UpValues is a pure-function?
In practice, I needs to define the UpValues of a user-defined function. For instance, the operation of function like differential formula , expansion and so on.
...
- 655
3
votes
1
answer
128
views
Define behavior of an expectation function wrt derivative
I wanted to calculate the expressions for Ursell functions
$$u_n(\sigma_1,\ldots,\sigma_n) = \frac{\partial}{\partial a_1}\cdots \frac{\partial}{\partial a_n}\log E(\exp\sum a_i\sigma_i)\big|_{a_i=0}$...
- 358
5
votes
2
answers
293
views
Why this upvalue doesn't escape from Sum?
Probably a hard question, but I decide to cry out loud :).
This is actually another problem I encountered when answering this question. Consider the following transform rule stored as an upvalue:
<...
- 68.4k
12
votes
1
answer
189
views
Strange behavior of UpSetDelayed together with MakeBoxes
In order to answer this question, I just stumbled into the world of UpValues. Though I managed to find a solution for the problem, I'm confused by my own code now 囧,...
- 68.4k
2
votes
1
answer
157
views
Writing my own error and warning messages
Question:
How is message handling implemented in Mathematica when applying Set to unprotected global variables such as $TimeZone...
- 602
4
votes
1
answer
246
views
How to tame the wild MMA?
MMA is a free country. But TOO free sometimes.
Just as an example:
Clear[a]
a[x_] == a[y_] ^:= Round[x] == Round[y]
{a[3] == a[3.01], a[3] == a[4]}
is {True, ...
- 85
13
votes
1
answer
179
views
AddTo regression in version 10
Bug (of Interval) introduced in 10, persisting through 12.2.
As we know we can assign special addition rules to symbols by using ...
- 15.1k
2
votes
1
answer
117
views
What workarounds are there to TagSetDelayed::tagpos?
My program creates an object based on an Association, with a custom head:
g = Gate[<| "key1" -> val1 |>]
I have ...
- 6,117
6
votes
1
answer
253
views
How to create fast functions based on units?
Using units is a good means for rapidly developing code, since it provides some error control.
Hovewer, using Mathamatica functions containing units appears to be copmutationally inefficient.
...
- 1,652