Re: Preventing unwanted threading by Inner
- To: mathgroup at smc.vnet.net
- Subject: [mg123544] Re: Preventing unwanted threading by Inner
- From: Chris Young <cy56 at comcast.net>
- Date: Sat, 10 Dec 2011 07:31:49 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <jbni23$47f$1@smc.vnet.net> <jbq49t$itm$1@smc.vnet.net>
On 2011-12-08 10:42:05 +0000, Ray Koopman said:
> This is a little better than my first suggestion.
>
> Inner[Times, {a1,a2,a3}, HoldForm /@
> {{b11,b12},{b21,b22},{b31,b32}}, Plus]
>
> a1 {b11,b12} + a2 {b21,b22} + a3 {b31,b32}
I see in the Help that HoldForm can help with preventing unwanted
expansion of a lot of formulas:
Display a sum of squares in unevaluated form:
\!\(
\*UnderoverscriptBox[\(\[Sum]\), \(i = 1\), \(10\)]\(\((HoldForm[
\*SuperscriptBox[\(#1\), \(2\)]] &)\)[i]\)\)
\!\(\*
TagBox[
SuperscriptBox["1", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["2", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["3", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["4", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["5", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["6", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["7", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["8", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["9", "2"],
HoldForm]\) + \!\(\*
TagBox[
SuperscriptBox["10", "2"],
HoldForm]\)