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Doing vector manipulations on Mathematica No..it didn't work..you can see this question that I put up about this, mathematica.stackexchange.com/questions/25696/… |
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asked | Doing vector manipulations in Mathematica (Part 2) |
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"wakeup" doesn't work After I copy-paste your code into the terminal it asks for [sudo] password and after putting in my password (the same which unlocks the computer?) it says, "patch: **** Can't open patch file /dev/fd/63 : No such file or directory" What is this? |
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asked | "wakeup" doesn't work |
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Doing vector manipulations on Mathematica Can this ":>" replacement trick be generalized to other cases as well? Like if I want to replace any occurrence of $2\vec{q}.\vec{k}$ by $\vert \vec{q} +\vec{k} \vert ^2 - q^2 - k^2$? (or to even start can I input a function with vector inner products? - algebraically and not with specific numbers and then do the above kind of replacement?) |
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May
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Doing vector manipulations on Mathematica More than that this is part of the definition of what is "Norm" of a vector. Why isn't this already known to Mathematica!? How else does one define Norm!? |
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Doing vector manipulations on Mathematica But conceptually its just one concept that the Norm of a negative of a vector is the same as the Norm of the vector. Can't this be made into just one rule to be specified? |
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Doing vector manipulations on Mathematica (..if it does all that a human would do with vector norms then I can go ahead use your script for various such large manipulations I would want to do - if the Norm factors are not combining well then I would have sieve through hundred of such expressions to pick by hand all the factors correctly!..) |
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Doing vector manipulations on Mathematica Great that there is a site like this! Its just impossible to know so many "tricks" with a software every time one has to do something - which is trivial to do by hand! So your "myform" specification also takes care of thinks like converting Norm[-x-y] to Norm[x+y] or Norm[x-y] to Norm[y-x] and all such possible combinations? |
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May
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Doing vector manipulations on Mathematica Thanks! Thats quite sophisticated! So you are basically putting in an extra rule to convert Norm[-x+y] to Norm[x-y]. But how does Mathematica understand this to convert Nor[-q] to Norm[q]? Does it on its own put a $0$ vector for the blank slot of y? |
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May
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Doing vector manipulations on Mathematica I had to put in Norm[-k2-q] and Norm[-q] intentionally to cause at least some simplification! Otherwise even those would have been messed! |
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May
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Doing vector manipulations on Mathematica @SimonWoods You can see this example - like if you put in, (F2s[q, k1]*F2s[-q, k2] F2s[k2 + q, k2 + k1])*(Norm[-q]^n Norm[-k1 + q]^n*Norm[-k2 - q]^n) // Expand // TraditionalForm then one can see that in various terms Norm[-q] and Norm[q] haven't been combined - hoping that everything else has worked out right! |
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May
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Doing vector manipulations on Mathematica @SimonWoods That does seem to help but it still doesn't seem to "understand" what a vector is. Like if I now evaluate F2s[p1,-k2] then it gives the answer in terms of stuff like Norm[-k2] - it doesn't understand that Norm[-k2] = Norm[k2]. Also once I have defined what what the function F2s is I want to be to able to evaluate the function on any combination of vectors like say F2s[k2+p1,k2+k1] wher k2, k1 and p1 are all vectors - how can this be done? I want it to behave like a function which takes two vectors and gives me its square/cube etc in the form I explained |
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Doing vector manipulations on Mathematica @bills I have added more details into the question. I guess now the question is more clear about what I want. |
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Doing vector manipulations on Mathematica You can see the edits that I made in the question. I guess now I have made my question more clear about what I want. It would be great if you can help! |
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Doing vector manipulations on Mathematica added 908 characters in body |
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Doing vector manipulations on Mathematica @bills Didn't get you. $F_2^{(s)}$ function is as defined in equation A.3 on page 19 of my linked paper. I want to be able to say take the square of it. How do I do it? |
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Doing vector manipulations on Mathematica I guess my question isn't well-framed. I didn't ask for such a thing. I am looking for an algebraic answer - and not for specific vectors you plugged in for $q1$ and $q2$. I can by hand calculate everything for general vectors - I guess there should be a way to do it in Mathematica also! |
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Doing vector manipulations on Mathematica @Jens Like, could tell me how I can get Mathematica to calculate say $(F_2^{(s)}(\vec{k},\vec{k}-\vec{q}))^2$ ? .. for example..or if you could help solve the previous question linked from here.. |
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asked | Doing vector manipulations on Mathematica |
