Re: simple questions about matrices

*To*: mathgroup at smc.vnet.net*Subject*: [mg26479] Re: [mg26472] simple questions about matrices*From*: Ken Levasseur <Kenneth_Levasseur at uml.edu>*Date*: Thu, 28 Dec 2000 02:52:19 -0500 (EST)*References*: <200012230346.WAA13016@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Cristian: Here is how you perform the matrix operations. Merry Christmas! Ken Levasseur Mathematical Sciences UMass Lowell Three credit on-line Introduction to Mathematica starts at the end of January: http://faculty.uml.edu/klevasseur/courses/m419/m419.html > (a) I have a (m,n) matrix a with integer entries.How can I construct > a separate list with the totals of adding the entries of either the > rows or columns? > In[3]:= m = Table[Random[Integer, {0, 10}], {4}, {5}] Out[3]= {{9, 1, 10, 4, 3}, {4, 7, 6, 9, 7}, {4, 5, 3, 3, 1}, {10, 8, 6, 4, 0}} In[4]:= rowsums = Apply[Plus, m, 1] Out[4]= {27, 33, 16, 28} In[5]:= columnsums = Apply[Plus, Transpose[m], 1] Out[5]= {27, 21, 25, 20, 11} > (b) How can I construct a (m+1,n) matrix where the new row's entries > are the sums of all numbers on each column? > In[6]:= Append[m, columnsums] Out[6]= {{9, 1, 10, 4, 3}, {4, 7, 6, 9, 7}, {4, 5, 3, 3, 1}, {10, 8, 6, 4, 0}, {27, 21, 25, 20, 11}} > (c) In general,how can I attach additional columns (o rows) to an > existing matrix? > Most of the more complicated operations can be done most easily by using the MatrixManipulation package: In[7]:= Needs["LinearAlgebra`MatrixManipulation`"] In[8]:= Information["LinearAlgebra`MatrixManipulation`*", LongForm -> False] AppendColumns MatrixNorm AppendRows PolarDecomposition BlockMatrix SquareMatrixQ CheckLinearity SubMatrix HankelMatrix TakeColumns HilbertMatrix TakeMatrix InverseMatrixNorm TakeRows LinearEquationsToMatrices TridiagonalMatrix LowerDiagonalMatrix UpperDiagonalMatrix LUMatrices VectorNorm MatrixConditionNumber ZeroMatrix Cristian Opazo-Castillo wrote: > Hello all: > > I hope that someone is still working and could help me with this... > > (a) I have a (m,n) matrix a with integer entries. How can I construct > a separate list with the totals of adding the entries of either the > rows or columns? > > (b) How can I construct a (m+1,n) matrix where the new row's entries > are the sums of all numbers on each column? > > (c) In general, how can I attach additional columns (o rows) to an > existing matrix? > > Thanks a lot and Happy Holidays, > > Cristian

**References**:**simple questions about matrices***From:*Cristian Opazo-Castillo <cropazo@vassar.edu>