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Math Forum / Math Software / Maple / October 2008Evaluating Symbolic Terms in a Matrix
Hello, I have the sequence of commands: A := matrix(2, 2, [a1, 0, 0, a2]); B := matrix(2, 1, [exp(a1*t), exp(a2*t)]); Mc := augment(B, A&*B); The result is a matrix with terms that are a function of a1, a2, and t. I am, however, unable to evaluate these terms for various values of the stated parameters. How may I proceed to evaluate terms of the matrix Mc? Thanks. -Joel > Hello, > [quoted text clipped - 11 lines] > > How may I proceed to evaluate terms of the matrix Mc? You could do something like this in Maple 12: > eval(Mc,{a1=1,a2=2}); But in some older versions of Maple you'd need an extra "eval": > eval(eval(Mc), {a1=1,a2=2}); BTW, you're using the old (and deprecated) linalg package. It's probably better to use the newer LinearAlgebra package.  SignatureRobert Israel israel@math.MyUniversitysInitials.ca Department of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada On Oct 13, 12:27 pm, Robert Israel <isr...@math.MyUniversitysInitials.ca> wrote: > > Hello, > [quoted text clipped - 26 lines] > Department of Mathematics http://www.math.ubc.ca/~israel > University of British Columbia Vancouver, BC, Canada That did it! Thanks! -Joel BTW: I am using Maple 9. > Hello, > [quoted text clipped - 15 lines] > > -Joel In Maple 9.5 (using the old 'linalg' package) you can get it to work using 'map': Nc:=map(x->subs({a1=1,a2=2,t=2},x),Mc); [exp(2) exp(2) ] Nc := [ ] [exp(4) 2 exp(4)] R.G. Vickson > > Hello, > [quoted text clipped - 26 lines] > > R.G. Vickson Thank you for the reply. I don't have much experience using Maple for linear algebra. What are the differences between the 'linalg' and 'LinearAlgebra" packages in Maple? More importantly, what are the reasons for defining a system of equations diffently? This is to say, why would I want to define a matrix using <<>|<>....<>> or matrix([[], [], ....[]]) or array([[], [], ....[]]) or any of the other ways it can be done? > > > Hello, > [quoted text clipped - 32 lines] > the differences between the 'linalg' and 'LinearAlgebra" packages in > Maple? LInearAlgebra has more functionality than 'linalg', but either serves well for many of the most common types of computations. I have found, however, that you cannot easily mix them up; a matrix formed using 'linalg' does not seem to be recognized properly by 'LinearAlgebra' and vice versa. To see the main differences, try loading them both, using with(linalg); (be sure to include the ';'), then try with(LinearAlgebra);. R.G. Vickson > More importantly, what are the reasons for defining a system > of equations diffently? This is to say, why would I want to define a > matrix using <<>|<>....<>> or matrix([[], [], ....[]]) or array([[], > [], ....[]]) or any of the other ways it can be done? >> > > Hello, >> [quoted text clipped - 38 lines] > 'linalg' does not seem to be recognized properly by 'LinearAlgebra' > and vice versa. Mixing is rather easy (but nearly never necessary): If A is a "linalg"-matrix, you can transform it to a "LinearAlgebra"-matrix by: B := Matrix(A); (capital M) If A is a "LinearAlgebra"-matrix, you can transform it to a "linalg"-matrix by B := evalm(A); > To see the main differences, try loading them both, > using with(linalg); (be sure to include the ';'), then try [quoted text clipped - 5 lines] >> matrix using <<>|<>....<>> or matrix([[], [], ....[]]) or array([[], >> [], ....[]]) or any of the other ways it can be done? |
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