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Jan
25
comment Is the divergence between Round and setting an explicit precision intentional or a bug?
the last point might deserve its own question. Id stop short of calling the rounding issue a bug unless the docs state a next to even rule is supposed to be applied.
Jan
23
comment Is there a build-in function converting a quantity to one with mixed units (such as feet and inches)?
+1 for extra credit I want fractional inches :-) ..
Jan
23
comment Mathematica shift-enter problem
i have had this exact issue in the past. Sometimes restarting the kernel a dozen times was required before being able to work normally. Unfortunately i cant tell you much more though, it went away on the last upgrade (to 9.0.1).
Jan
21
comment Is this caused by round-off errors?
see if this gets you a simpler form Integrate[ E^(c x) (1 - x)^a x^b, {x, 0, 1},Assumptions->Element[{a,b},Integers]]
Jan
20
comment Why is (-1.)^2. a complex number
no flags. See the edit though - the results may differ depending on how the compiler optimizes the code.
Jan
20
comment Why is (-1.)^2. a complex number
Using Chop@Re@ in the compiled function fixes things without impacting performance much (I realize that's not really the point of the question though )
Jan
20
comment Why is (-1.)^2. a complex number
FWIW, my 9.0.1.0 linux throws a "proceeding with uncompiled version" error on the real 2.
Jan
20
comment Partition a range of integers into triples
related : mathematica.stackexchange.com/questions/71827/…
Jan
20
comment reading data, one number at a time, from file to be used in a formula
the best approach is usually to Import the whole file, and process from there. If you really want to read a line at a time the relevant commands are OpenRead , ReadList , etc.
Jan
19
comment Embed 3D objects from Mathematica, in a pdf
I see on the jReality site forum there is a discussion of importing from mathematica.
Jan
17
comment How to make the result of Piecewise be a closed interval?
I think you have correctly implemented the formula. try specially treating the last interval If[ i<Length[knots]-2,Piecewise[..<],Piecewise[..<=]].
Jan
17
comment How to speed up the plotting of B-spline curve?
you need to look at the Piecewisw expression, then that will make sense.
Jan
16
comment How to determine if directories with executable permission and not
just Run[" test -x dirname" ] works as well, for those with older versions..
Jan
16
comment How to determine if directories with executable permission and not
following up on my comment, FileNames[__,dir] just returns an empty list if dir is not executable (even though ls will show the directory contents ), so you cant use this.
Jan
16
comment Partitioning with constraints on subsets
+1 Time form me to go study graph theory.
Jan
16
comment Filtering outliers
Looking at the answer, it seems a bit different just because the data in this case lends itself to a nice analytic fit.
Jan
16
comment PlotRange->Automatic the exact function used to calculate outliers
interesting question, but I think as a practical matter, even if you knew exactly the criteria, in order to to replicate Plot's result you would need to replicate Plot's recursive function mapping to use it.
Jan
16
comment How to speed up the plotting of B-spline curve?
your Piecewise function is defined for knot[[1]]<=u<knot[[-1]]. You need to make the last interval inclusive (<=knot[[-1]]). The out of bounds default is {0,0}, it should probably be undefined.
Jan
15
comment NDSolve ensemble of initial points
its not clear where you need help, how to solve the equations, how to plot the results, how to generate random initial points, (all of the above?)
Jan
15
comment PlotRange->Automatic the exact function used to calculate outliers
relevant.. mathematica.stackexchange.com/questions/61714/…