Michael Wijaya
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 Jun14 revised How to substitute numeric values in a symbolic Jacobian matrix? Stylistic changes, added method to generate vector of variables symbolically Jun14 answered How to substitute numeric values in a symbolic Jacobian matrix? Jun14 awarded Civic Duty Jun13 comment Interprocedural optimization It is possible to compute PrimePi[n] without enumerating all prime numbers less than $n$. See for example Lehmer's recursive formula. Jun13 revised How do you check if there are any equal arguments(even sublist) in a list? Changed the name of the second function since it is no longer a Boolean function. Jun13 revised How do you check if there are any equal arguments(even sublist) in a list? Include modifiication to keep track of repeated elements as per OP's request Jun13 answered How do you check if there are any equal arguments(even sublist) in a list? Jun13 comment Checking if the roots of a function are real You can try checking that the imaginary part is zero. We can get the list of roots using x /. {ToRules[Reduce[LegendreP[6, x] == 0, x]]}. Then we map Im to each root using Map[Im,%], which gives {0,0,0,0,0,0}. This seems to suggest that the roots are real, but I am not 100% sure. Jun13 comment Splitting a list @BrettChampion At one point I made a list of things I liked about Mathematica, and it included the fact that everything is an expression. Lisp popped up when I researched the roots of this feature. On a related note, that book really did teach me to write recursions! (Always ask null?, etc.) Jun13 answered Splitting a list Jun12 awarded Nice Question Jun10 revised Implementing Central Symmetry Chose a better reference, more accurate definition of orthogonal group Jun10 comment Wagner's trick to monitor FindRoot no longer works in Mathematica version 8 @AlexeyPopkov Thanks! Could you also include a link to the documentation where that "standard" trick is explained? I apologize for making so many requests of you. Jun9 comment How to Clear a symbol with subscript in Mathematica? By the way, there is still one typo in your reply. You wrote Unset[Subscript[[Lambda], 0]], which is missing a backslash. Jun9 comment How to Clear a symbol with subscript in Mathematica? I started with a fresh Mathematica session. In that case, Subscript[\[Lambda], 0] = 1 followed by Unset[Subscript[\[Lambda], 0]] does not generate any warning message. I can even do the assignment Subscript[\[Lambda], 0] = 2 after that. If you just want to clear $\lambda_{0}$, you probably do not need to use the Notation package. Maybe you made the problem worse by calling functions from that package? Jun9 comment How to Clear a symbol with subscript in Mathematica? Have you tried Unset[Subscript[\[Lambda], 0]] instead of Unset[Subscript[Lambda, 0]]? Jun9 accepted Wagner's trick to monitor FindRoot no longer works in Mathematica version 8 Jun9 comment Implementing Central Symmetry Szabolcs' image uploader came in handy. Jun9 answered Implementing Central Symmetry Jun9 comment Wagner's trick to monitor FindRoot no longer works in Mathematica version 8 @AlbertRetey I am not sure I understand how that trick works in this context. Could you post an answer based on that?