Column vectors should be interpreted as simple lists where
- To: mathgroup at smc.vnet.net
- Subject: [mg121320] Column vectors should be interpreted as simple lists where
- From: "Christopher O. Young" <cy56 at comcast.net>
- Date: Sat, 10 Sep 2011 07:29:13 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
It's a nuisance not to be able to enter data for points in the most readable and intuitive form, i.e., as column vectors, without having to Flatten out each column vector. The best workaround I could come up with was to use the following to convert lists of points to lists of lists. It's good that we don't need to waste space with parentheses, though. We can just type in the column vectors as column arrays using Control-return. But it would be even better if there were something close to the regular square bracket notation, which is the accepted mathematical notation, and also takes less space-consuming than curved parentheses. If WRI could also stop insisting that all input is boldface, users could use the excellent, time-honored, intuitive notation of having bold-face for vectors and matrices and regular type for scalars. Would this be so hard to implement? Maybe slightly different square brackets could be used, accessible via holding down the option key. It would be also be a huge time-saver if there were a way to get bracket pairs via holding down the Control-key, say. I.e., Control-( would type a _pair_ of parentheses, Control-[ would type a pair of square brackets, etc. There's a picture at http://home.comcast.net/~cy56/ColumnVectors.png and a notebook at http://home.comcast.net/~cy56/ColumnVectorsAsPoints.nb . MF[x_] := Map[Flatten, x] Graphics[ { {Directive[Thick, Gray], Line[Table[{ {x}, {Sin[x]} } , {x, 0, 6.3, 0.1}] // MF[#] &]}, {Directive[Dashed, Blue], Line[{{ {2}, {0} } , { {2}, {Sin[2]} } , { {0}, {Sin[2]} }} // MF[#] &]}, {Directive[PointSize[0.02], Blue], Point[ { {2}, {Sin[2]} } ] // MF[#] &} }, Axes -> True ]
