# Questions tagged [expression-construction]

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### How to modify the order of symbols to make the result look more well and use some fixed expression 1-q, 1-c-q and so on?

In most cases, my expressions are quite complex, like the following expr and expr2. How can I make them look better, for instance, I want to use expressions like 1-q or 1-c-q and so on.
41 views

### Conversion of an expression to function yields Tag Plus in ... is Protected error

I'm trying to implement polynomial interpolation. My current implementation involves generating an expression that is the final equation that will be plotted. While plotting the function itself works ...
163 views

### Precise control of fraction expression

It seems that expression for fraction differs when the number of terms in the numerator is more than 2. ...
• 4,047
106 views

### Elegant way to validate expression?

Suppose I'm using the expression Person[fn_String, ln_String] as a data expression, and want to prohibit the creation of expressions where ...
1 vote
98 views

### Fitting an inverse power law [closed]

Is there any reasonably fast way of finding a function of the type that best fits a given data, for some K and n? For example, the following data closely follows an inverse power law ...
• 4,179
48 views

• 51
1 vote
173 views

### How to sort out/ extract positive and negative powers as list?

I have the following expression expr = x1^d1 * x2^d2 * x3^d3; where d1,d2,d3 can contain negative values/expression i.e. in ...
• 1,604
43 views

### Formula: setting parameters vs replacement, different results?

I have a question that may sound stupid and have an easy answer - but I currently do not see it. I have defined a function of four variables, $f[a,b,c,d]=...$, in what I think is correct Mathematica ...
51 views

### Nest expressions of several arguments

I have the following function: Q[r_, f_, s0_] := Q[r, f, s0] = F[r, s0] D[f[s0], s0] By calling Q[r, Q[r, f, s0], s0] I ...
• 153
165 views

### Computations with OptimizedExpressions without completely expanding them

I have to manipulate huge expressions that are rational functions of many (∼30) variables with integer coefficients. Storing them just as a ratio of two polynomials would be impractical. But they can ...
• 7,163
60 views

### How to do an arbitrary expression growth in Mathematica?

I want to write a function that can be used to grow an expression from a seed or another existing expression based on part specification. ...
• 9,113
171 views

### Help with printing table data

I am looking for the way of building a Table in a fast way. My true table evaluates huge functions with a system of differential equations . Let us for simplicity consider this: ...
• 57
48 views

### How to generate nested expression?

I've found some related questions, but nothing has really helped me to do what I want to do. Given a list of variables L and a parameter ...
• 1,593
1 vote
105 views

### Is there a good reason why Slot[] is not an atomic expression?

Here's a good reason why I think it should be, Map[ If[AtomQ@#, #->"is an atom", #->"not an atom"]& , {"hello",Range@3, # &} , {-1} ] ...
• 2,040
258 views

### Using With[...] with a list specification as a variable [duplicate]

If you have some defined function, say f[a_, b_ c_, x], one can initialize this by using With[...] as ...
• 2,480
1 vote
86 views

### Summation and product term expressed in Mathematica [duplicate]

I have the following term which I would like to express correctly in Mathematica: $$\sum_{i=1}^{m}\frac{1}{\prod_{j=1,j\neq i}^m(\rho_i-\rho_j)}$$ This means that for $m=3$ for example you should ...
• 181
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### Displaying positions in expression tree

Can one display the position of each character in an expression tree? For instance: g[h[i, h], l] should be displayed using TreeForm where each character is ...
• 1,596
124 views

### How to pass an expression as list elements for a Mathematica command

I'm trying to build a generic function that will calculate sums on different iterators. To simplify let consider: ...
65 views

### Transform String to Expression [duplicate]

I have a variable postVector and another called CHKpostVector. Both are global variables. Only the variable ...
• 159
3k views

### How to define constants in Mathematica like c1,c2,c3,...cn?

Manually defining the constants is tedious if the 'n' is large. how to do this?
• 1,699
103 views

### Generate multivariate monomials with constraints

I'm trying to generate multivariate monomials in variables $p_1, \ldots, p_n$. Each monomial has either $p_i$ as a factor, otherwise $(1-p_i)$. I need to generate all monomials which have exactly $k$ ...
• 131
95 views

### Creat a matrix with boundary condition

I would creat a symmetric matrix, but how can I set the boundary in Subscript? ...
• 1,816
231 views

### Constructing expressions using Sum vs Array[... Plus] vs Plus@@Table[...]

For constructing a sum of terms which are symbolic, I noticed that in addition to ...
• 19.5k
85 views

### Translation of GLSL expression (2) [closed]

What's the most compact WL translation of this GLSL expression: length(max(vec2(x,y),s)) ?
• 598
99 views

### Generate a system of linear differential equations from a coefficient matrix

I want to generate a system of linear equations that is stable. For that I generated random coefficients and divided the 10 by 10 matrix by the largest eigenvalue and set the diagonal to -1: ...
• 2,955
1k views

### Is expression in Mathematica well defined?

According to Mathematica, everything is an expression. So an atom is also an expression. But in other parts of documentation, they say that an expression is of form ...
• 1,049
1 vote
106 views

### How to send Map[Plus[1, #] &, {1, 2, 3}] to Mathematica from C# via IKernelLink?

Here is a piece of my code ...
• 11
1k views

### Replace element of a matrix with condition

consider a matrix $\left( \begin{array}{ccccc} 0 & 0 & 1 \\ 1 & 0 & 0 \\ 1 & 1 & 0 \\ \end{array}\right)$ How do I do a program that does these steps 1-Replace each ...
463 views

### Generating a family of 0-1 matrices satisfying a particular property

I'm looking for an elegant way to generate the set of all possible matrices that satisfy the following properties: Each matrix has 9 rows and c columns, where 1<=c<=9. Each matrix has exactly ...
• 183
179 views

### Graph that shows how symbols are used in an expression

I would like to make a graph to show how symbols build up an expression. For example, the matrix multiplication  \left( \begin{array}{ccc} a & b & c \\ d & e & f \\ \end{array} \...
• 1,631
51 views

### Producing the same output as Tuples[{0, 1}, 4]? [closed]

How can I use the functions decimalToBinary and padWithZeros to produce the same output as ...
324 views

### Handling multi-part equations

How are multi-part equations best handled? For example, take the torsion equation: We could express part of this equation like this: ...
• 4,048
1 vote
95 views

### How to generate expression a + a1 e1 + a2 e2 + a12 e12 (subscripted)?

Sorry to ask this twice. I thought I could get away with just a0 + a1 e1 + a2 e2 + a3 e1 e2, but for my application I can't. I can generate a + a{1} e1 + a{2} e2 + a{12} e12 (subscripted), but that's ...
• 425
212 views

### How to make RawBoxes to be Expression

expr = First@ Level[Values@ WolframLanguageData["Plot", EntityProperty["WolframLanguageSymbol", "DocumentationExampleInputs"]], {3}] Plot[Sin[...
• 26.3k
1 vote
356 views

### How can a generate an expression like a0 + a1 e1 + a2 e2 +a3 e3 + a4 e1 e2 + a5 e1 e3 + a6 e2 e3?

I wish to input n and then generate an expression. It would look like the above when $n = 3$. I would like to use subscripts for ...
• 425
359 views

### a function to extract all subexpressions from an expression

Can somebody help me with a function f such that it extract all sub expressions (i.e. looking down the expression tree) from any expression given to it and also a ...
• 9,113
80 views

### Proper formulation of Do expression [closed]

I'm having trouble with the following code: ...
• 189
1 vote