wolfram-mathematica

The following code creates a diagram of a certain calculation. My problem is that even though the terms in denominator are in a nice order, after applying Plus on it, they get rearranged arbitrarily. Any suggestions how to force the original order to be kept? (source: yaroslavvb.com ) r[i_] := Floor[(i - 1)/n] + 1; c[i_] := Mod[i, n, 1]; adj[a_, b_] := Abs[r[a] - r[b]] + Abs[c[a] - c[b]] == 1; indsetQ[s_] := Not[Or @@ (adj @@@ Subsets[s, {2}])]; indsets[k_] := Select[Subsets[Range[n^2], {k}], indsetQ]; twoColorGraph[g_, seen_, lbl_] := Module[{radius = .22}, vcoords = # -> {c[#], n - r[#]} & /

I want to use gridlines to create an effect of millimeter graphing paper on a 2d graph, to show how multi-variable function depends on 1 variable. The scales of different variables differ a lot, so my naive approach (that I have used before) does not seem to work. Example of what I have at the moment: << ErrorBarPlots` Cmb[x_, y_, ex_, ey_] := {{N[x], N[y]}, ErrorBar[ex, ey]}; SetAttributes[Cmb, Listable]; ELP[x_, y_, ex_, ey_, name_] := ErrorListPlot[ Cmb[x, y, ex, ey], PlotRange -> FromTo[x, y], PlotLabel -> name, Joined -> True, Frame -> True, GridLines -> GetGrid, ImageSize -> {600} ] Both

Every time I have to do this I "invent" a different way. Time to standardize. I suspect there is some default command I overlooked ready to do this, so I am sorry in advance if the question is too trivial. What is the better (memory, performance) way to get: combinations[{1,2,3},2] = {{1,2},{1,3},{2,3}} with arbitrary elements in the input list, of course. cah Subsets[{1, 2, 3}, {2}] is the built-in way. Before Subsets was added as a core function, the Combinatorica function KSubsets was available. Needs["Combinatorica`"] KSubsets[{1, 2, 3}, 2] (* {{1, 2}, {1, 3}, {2, 3}} *) Combinatorica

I'd like a function AnyTrue[expr,{i,{i1,i2,...}}] which checks if expr is True for any of i1,i2... It should be as if AnyTrue was Table followed by Or@@% , with the difference that it only evaluates expr until first True is found. Short-circuiting part is optional, what I'd really like to know is the proper way to emulate Table 's non-standard evaluation sequence. Update 11/14 Here's a solution due to Michael, you can use it to chain "for all" and "there exists" checks SetAttributes[AllTrue, HoldAll]; SetAttributes[AnyTrue, HoldAll]; AllTrue[{var_Symbol, lis_List}, expr_] := LengthWhile[lis,

This question is in a way a continuation of the question I asked here: Simple way to delete a matrix column in Mathematica to which @belisarius and @Daniel provided very helpful answers. What I am generally trying to do is to extract from a matrix A specific lines and columns OR what remains after what those specified are removed. So this can be formally writtewn as, find TakeOperator and Drop Operator such that: TakeOperator[A,{i1,..,ip},{j1,...,jq}]=(A[[ik]][[jl]]) (1<=k<=p, 1<=l<=q) = Table[A[[ik]][[jl]],{k,p},{l,q}] We note Ic={i'1,...,i'p'}= Complement [{1,..., Length[A] },{i1,...,ip}];Jc

I'm in the process of creating a notebook that contains a style to write documents. I would like Mathematica to behave similar to LaTeX in the sense that when I write a "Definition" cell then it will write "Definition [Chapter#].[Definition#]" . To see what I mean do the following. In an empty notebook create a cell and modify the style to "Chapter" . You can do this by selecting the cell and the going to Format->Style->Other , enter "Chapter" . Now go to Format->Edit StyleSheet... . Enter Chapter in the input box. This will generate a cell labeled Chapter. Select that cell, and click on Cell-

Is it possible to see full version of a Message that got truncated? IE, I see something along the lines of 0.105309,0.394682,<<20>>,<<20>>,<<20>>,0.394631 in the Messages window. I'm guessing <<20>> represents omitted parts, how do I get the whole thing? The function called is FindMaximum on a problem with 50 variables. Update: Simon's answer seems to work for general messages, also I found an approach that's specific to capturing the FindMaximum "not a real number" message. To get the point which causes FindMaximum to fail with "not a real number" message you can do the following (redefining