Search Results

Construct f (a numeric function) which takes multiple arguments with the following property: The single argument case $f(x_1)$ is meaningless, and the two-argument function $f(x_1,x_2)$ is the base c …

Why are there MapThread and MapIndexed but no analogous functions for Scan? What is the recommended way to Scan over a pair of datasets (ScanThread), or over an ordered dataset (ScanIndexed)? Edit …

Consider a list of symbols: mySet = {a, b, b, c, a, b, c, d}; I would like to form the product of duplication numbers. In the example above, I have 2 a's, 3 b's, 2 c's and 1 d. So the result I ne …

Some code generates a polynomial, and has the form: expr = Plus[a[i],b[i],c[i],d[i]] I need to apply f to each term. To do this, I use Map: Map[f, expr] (* f[a[i]] + f[b[i]] + f[c[i]] + f[d[i]] …

I have a really long sequence of Symbols inside a function, say nonCommute[a,b,c,e,e,f,g,b,i,j], and I am implementing a recursive algorithm using RepeatedReplace with the rule: rule = nonCommute[lef …

I would like to write a Rule that mimics built-in Distribute[], but one that distributes Plus over a function f, while skipping a level (which for me, has head=List). Here are examples of what I need …

I have an expression like this F[G[1, b], G[3, y], G[4, y], G[5, u]] that I would like to Transpose to obtain G[F[1, 3, 4, 5], F[b, y, y, u]] Since Transpose doesn't act on expressions (with hea …

I want to mimic the functionality of Collect[expr, {vars}, func], but with the following modification: The function f that is applied to each coefficient is different, and depends on which variable i …

I would like to know if there is a nice functional way to code up a MapList which applies f to each element of expr and returns a list of the results obtained. Here is my implementation: MapList[f_, …

I'm getting completely stumped on writing a function makeIterate that constructs an iterated structure out of a list of functions e.g. {f, g, h} and a list of corresponding arguments {d1, d2, d3} (sam …

I have written code that does carries out the following task: Construct a fully symmetric rank-$P$ "tensor" out of a collection of user-input rank-1 vectors, and a rank-2 symmetric tensor $h$. The n …

I need to generalize the SeriesData object for my own purposes. One of the things I need to do is to reimplement code to multiply product of series. I've made two attempts at this, and both of them a …

I need to sum over all possible permutations, multiplied by the Signature of each permutation of a given list of symbols. But, I don't know how to determine the Signature of each particular permutati …

I came across the following two internal functions SimplifyDump`AbsToSign and SimplifyDump`SignToAbs that have been written procedurally. Here are the source codes: AbsToSign[expr] attempts to co …

I would like to write a searcher like FreeQ that looks for a Symbol (or Head) in an expression, but confines its search outside of subexpressions that have a particular Head. Because expr can get hug …