Items tagged with large-expressions

I have a question that I hope someone can help with. We perform extreme value analysis on expressions. My this I mean that we evaluate expressions for each combination of min or max values of each variable in the expression. For example, the expression a*b+c*d has 4 variables and we would evaluate the expression for all of the 16 combinations of a,b,c, and d to determine the worst-case result. I understand that the worst case results may not occur at the extreme values of the variables, but that is a different question.

 What I would like to know is if there is a way to reduce the number of calculations by splitting the expression into independent parts. In the example above, the expression consists of 2 parts a*b and c*d. These parts could be evaluated separately. Each has 2 variables, and each would therefore requires  4 combinations of variables to determine the extreme values of the results. So in this case, the number of calculations is 4+4=8, which is half of the initial 16  runs as would be done with a full-factorial analysis. Also, because each calculation is done on only part of the original expression, each calculation takes less time.

Is there a way to find the independent parts of an arbitrary expression so that each independent part could be evaluated separately to speed processing?

Thanks

Hello. Using a symbol ":", you can hide the derivation of the expression. However, it lost the label of expression. Can I hide the expression of retaining the label for further use? It would be handy when working with large expressions.

Hi guys,

I'm trying to find the solutions to a nonlinear equation system:

mysol := solve({J*a = m*g*l*st-m*l*(c*cp*st+d*sp*st), cx*ux = cMx*xd+(Mx+m)*c+m*l*(-cp*pd^2*st-cp*st*td^2-2*ct*pd*sp*td+a*cp*ct-b*sp*st), cy*uy = cMy*yd+(My+m)*d+m*l*(2*cp*ct*pd*td-pd^2*sp*st-sp*st*td^2+a*ct*sp+b*cp*st), (-M*l^2*st^2+J)*b = m*l*sqrt(d^2-2*d*ct+ct^2+c^2*ct^2+(c^2*sp^2-2*c*cp*d*sp+cp^2*d^2)*st^2)}, {a, b, c, d})

The solution contains various implicit solutions with RootOf's. When trying to evaluate them by typing

allvalues(mysol);,

the returned set of solutions is about 800.000 characters long, but unfortunately contains various "+ [...15295 terms...] +" elements, and thus not displaying the full solution. The limits on the precision tab in the maple options are all disabled.
Does anybody know how to display the full expression, although it gets very long?

Thank you in advance,

Martin

I need some sugestions how to expand terms raised to some exponent within an expression. How to simplify,How to collect terms with some conmon factor within the same expression relativistic_11.mw

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