Re: Simply but handy question
- To: mathgroup at smc.vnet.net
- Subject: [mg124883] Re: Simply but handy question
- From: Paul Whelan <jediwhelan at googlemail.com>
- Date: Fri, 10 Feb 2012 05:57:49 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <7BB0E96E72E84E41B24A1FF8ED13F5E6156AA9F3DA@IE2RD2XVS581.red002.local>
Hi Alexei,
this is a nice solution ! thanks
On Thu, Feb 9, 2012 at 8:52 AM, Alexei Boulbitch <Alexei.Boulbitch at iee.lu>wrote:
> Dear group members,****
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> I am new to mathematica (well, I'm not actually but I haven't used it****
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> in 5 years +).****
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> Is there an easy way to return a matrix X of 1's and 0's to test****
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> whether the entries in Y****
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> are different from zero.****
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> i.e.,****
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> if Y = {{a,b},{0,c}}****
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> Then X would return****
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> X = {{1,1},{0,1}}****
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> This would be handy for very large or complicated matrices where one****
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> would like to know if specific entries are zero?****
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> Many thanks,****
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> Paul****
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> Hi, Paul,****
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> Try this: ****
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> matrix1 = {{a, b}, {0, c}};****
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> matrix2 = {{a, b, 0}, {c, 0, 15}, {0, 2, d}};****
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> g[a_] := If[a =!= 0, 1, 0];****
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> Map[g, matrix1, {2}] // MatrixForm****
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> Map[g, matrix2, {2}] // MatrixForm****
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> ** **
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> Have fun, Alexei****
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> *Alexei BOULBITCH**, Dr., habil.*****
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> IEE S.A.****
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> ZAE Weiergewan,****
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> 11, rue Edmond Reuter,****
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> L-5326 Contern, LUXEMBOURG****
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> ** **
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> Office phone : +352-2454-2566****
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> Office fax: +352-2454-3566****
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> mobile phone: +49 151 52 40 66 44****
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> e-mail: alexei.boulbitch at iee.lu****
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