Questions tagged [rule]
Questions about transformation rules in Mathematica--constructs that let you set, or programmatically modify, local values for expressions.
368 questions
1 vote
1 answer
102 views
Why is rule matching FiniteField not working? [closed]
I am introducing a rule: $Post = # /. x_?NumericQ FiniteField[q_?PrimeQ] [s_] :> FiniteField[q] [x] FiniteField[q] [s] &; But for some reason, upon ...
- 3,862
0 votes
2 answers
130 views
Why does a replacement rule fail for a custom defined function but works for a generic symbol?
I'm pretty new to Mathematica and I have a question about how to deal with replacement rules in presence of function definitions. Basically I want to implement a mean/covariance calculator, in the ...
- 1
4 votes
1 answer
268 views
treating the rule itself as a pattern
My goal is to count cases of {"Yes", _, _} -> "Yes" and {"Yes", _, _} -> "No" in the set below using HoldPattern to treat the rule itself as a pattern. ...
- 1,484
3 votes
2 answers
192 views
Substituting product of functions with function of several arguments
I have expressions of the general form as in an example below (\[Pi]^10 T[4]^2)/9240 + (\[Pi]^10 T[3] T[5])/4620 Here T[n] is ...
- 33
4 votes
7 answers
543 views
1 vote
0 answers
79 views
How can the reverse of a rule which contains two arguments be defined in Mathematica? [duplicate]
Suppose I have a rule in Mathematica: x -> x[a] defined under some variable. Is there a way I can use the reverse of the rule ...
- 3,028
2 votes
0 answers
89 views
Doubt about ReplaceRepeated?
I made the following code: L={{1,2},{2,3},{2,4}}; R:=(L=(L/.{x_,y_}:>Splice[{{x,y},{x,x},{y,y}}]/;MemberQ[L,{x,y}])//Union) When I run R three times, I get: <...
- 5,613
3 votes
2 answers
204 views
Pattern match about Times default value
I want to divide a product into two pieces, one is the terms of form f[x, _], the other is the leftover factors free of x: ...
- 165
7 votes
3 answers
412 views
How to implement rule based transitive closure?
Given a relation L, we can make the symmetric closure using rules as follows: ...
- 5,613
0 votes
0 answers
66 views
How to apply dependent rules in a complex expression?
I am working with a complex expression, $L_0$, which I need to simplify iteratively using a series of dependent replacement rules. Here's the structured approach I am trying to implement: Start with ...
- 544
2 votes
0 answers
170 views
Perturbation theory. Get xAct tensor component. Substitution for xAct tensors
I work with perturbations in FLRW metric with arbitary curvature. I'm following Weinberg's book. In modified gravitation theory there is additional tensor S and I need to find it's perturbation in the ...
- 21
1 vote
3 answers
256 views
0 votes
1 answer
74 views
Cross derivative rules
I am trying to generalize the condition Derivative[1, 0][ℒp][t, ϕ] -> Derivative[0, 1][ℒp][t, ϕ]/l for $\ell$ a constant, through the following rule ...
- 173
4 votes
1 answer
161 views
How to write a rule that matches alternatives but return one of them always?
Consider the following rule: $rule={"Period ID"|p:"Period":>p}; This rule will match ...
- 10.4k
2 votes
1 answer
116 views
Removing `circular rules'
Say that I have a huge list (>300.000 elements) of polynomial equations and I want to simplify these by looking for some simple equations of the form x[i] == _ ...
- 1,783