Questions tagged [semantic-matching]

Posts about semantic pattern matching rather than syntactic pattern matching (which is the built-in pattern matcher of Mathematica) e.g. "Why x^3 /. x^2->a doesn't work!"

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ReplaceAll with Powers

If I run the following code: a^2/b^2 /. {a/b -> c} I'm getting output: a^2/b^2 How can I obtain ...
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2 votes
0 answers
151 views

What is Wolfram's equivalent of Maple's algsubs?

Maple has two primary substitution functions. subs - which is similar to ReplaceAll in WL. algsubs - which does replacement but takes into account the algebraic ...
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2 votes
2 answers
225 views

How do you get substitution to recognize a derivative?

I have a simple expression involving a derivative: x[t_] = Q/T[t]; Simplify[Derivative[1][x][t] /. Q -> x T[t]] That produces:$$-\frac{x T'[t]}{T[t]}$$I have ...
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5 votes
3 answers
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ReplaceAll (/.) not working as expected

I am trying to replace some variables in the form of n*wt with wt. However, I came across some cases where the ...
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4 votes
2 answers
311 views

Definition of a general rule

By defining: rule = Sqrt[expr_^2] :> expr; and writing: Sqrt[x^2] /. rule I get: x which is what is desired (...
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0 votes
1 answer
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Parsing time interval strings as "Uncertain" Time Intervals

Problem: I have strings of form "[d1, d2]" or sometimes just [d1] where d1 and ...
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8 votes
1 answer
1k views

How to find multi-word synonyms?

I’m looking to write a semantic distance function for phrases (5 words or less) that can map multi-word synonyms together. My domain is e-commerce fashion - here are some required examples for a ...
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0 votes
1 answer
168 views

Using Semantic Import to do an Excel-like VLookUp using Mathematica

I'm following an example provided in the following Stack Exchange Link but, using a different approach. My data is contained in an Excel workbook called "Input Workbook.xlsx" as shown here: I ...
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3 votes
3 answers
141 views

Identify complex expression and replace

I'm having trouble finding a way (if there is) to analyse an expression, identify a complex pattern in it and then replace it with another thing. I think it will be easier to explain my problem with ...
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  • 33
4 votes
1 answer
160 views

"Smart" substitution of subexpressions

I have the following question. An expression, which I want to simplify contains several subexpressions which appear quite frequently all over the place. To optimize simplification I would like to ...
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  • 223
3 votes
0 answers
122 views

SemanticImport extremely slow with "Number" format

With the following definition: col = "num\n" <> StringRiffle[Table[i, {i, 1000}], "\n"]; I do not understand why the ...
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2 votes
2 answers
153 views

Sets of identical equality/inequalities

So I've used Mathematica for some months, but I never noticed this sort of thing about it, namely: (a > b) == (b < a) which are supposed to be identical ...
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  • 183
0 votes
1 answer
179 views

Simplifying expressions

Let's define a function $\Omega(x,y)$ ...
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58 votes
4 answers
10k views

Can I simplify an expression into form which uses my own definitions?

This seems like a simple thing to do, but I couldn't find anything relevant from Mathematica documentation. So suppose I have an expression: a*b/(a + a*Cos[a/b]) ...
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