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Jan
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comment LinearSolve on non-square matrices?
That applies N only to the symbol SparseArray and thus is equivalent to SparseArray@foo. You can easily verify that by noting that the result consists of integers, not of m,achine-precision numbers. Note that the point is not the application of N, but the fact that I have a sparse array with numeric values; Applying N is just a convenient way to get that.
Jan
14
comment Randomly Multiply OR Divide by a Random Number?
Yes, exactly: You multiply with an uniform distribution between 0.1 and 1. Which is not the same as dividing by an uniform distribution between 1 and 10.
Jan
14
comment Randomly Multiply OR Divide by a Random Number?
More importantly, it gives a different distribution. The inverse of an uniformly distributed variable is not uniformly distributed.
Jan
14
asked LinearSolve on non-square matrices?
Nov
27
awarded  Generalist
Oct
29
comment Why is a symbol still found after changing its context?
From further tests, it seems that everything generating a message works; not only Update[""] but also 1/0. Anyway, I now noticed something different: My previous tests had all been by directly entering into the kernel; now I tried in the notebook, and there the context assignment seems to work immediately.
Oct
22
comment Why does Information[]-Function (question mark) prepend additional contexts to $ContextPath?
Internal`InheritedBlock[{$ContextPath},?Sin] restores the $ContextPath afterwards, I guess that should be safe.
Oct
22
comment Why is a symbol still found after changing its context?
Interestingly, Update with any invalid argument also seems to work (so Update["hello world"] works, but neither Update[] nor Update[Unevaluated@x] nor Update with any function related to symbols, expressions or context I've tried).
Oct
20
comment Plot of function-generated lists: Why does this workaround not work?
I'm comparing with the code I posted in my question (the one that gave the wrong curves). That code makes only 78 calls to f (tested on Mathematica 8.0). However I defined the function for counting as f[x_?NumericQ] := {count++; x, x^2}.
Oct
20
comment Plot of function-generated lists: Why does this workaround not work?
But all those do the equivalent of Plot[f[x][[1]], f[x][[2]],{x,0,1}]. That is, the function is evaluated twice (this can easily be verified by incrementing a counter in the function; with my version, there are 78 calls, with any of yours, there are 158). The whole point of that construction is that this extra call is avoided (as the calls of the actual function are expensive).
Oct
20
accepted Plot of function-generated lists: Why does this workaround not work?
Oct
20
comment Plot of function-generated lists: Why does this workaround not work?
Thanks, that makes sense. I now tested the call order, and indeed, after an initial single call to each, there follows a row of calls only to fwrap1, and then another row of calls only to fwrap2. If you turn your comment into an answer, I'll accept it.
Oct
20
asked Plot of function-generated lists: Why does this workaround not work?
Oct
20
comment Why is 13 the smaller height dimension of a Graphics?
Just for the record, I just tested your code on Mathematica 8.0 (Linux), and there the minimum seems to be 12, and the only anomaly is at ImageSize height 12 where the value is 13 instead of 12.
Oct
20
answered Skipping “middle” Optional Arguments
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