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Apr
10
comment Adapt the code to produce a three column table containing the values of n, etc. (Numerical integration)
@Nasser Actually I just made a pact with the devil and got the ability to figure out the use of the code, at the cost of being unable to use Do in my answer :D
Apr
10
answered Adapt the code to produce a three column table containing the values of n, etc. (Numerical integration)
Apr
9
awarded  Enlightened
Apr
9
comment How can i subtract a surface from another
……我想我猜的没错吧?你的母语是汉语吧?你真的明白accept the answer和click the checkmark sign的意思吗?也就是说,至今为止你得到的答案没有一个让你满意的吗?
Apr
9
comment How can i subtract a surface from another
那啥,同学,我姑且确认一下,你知道上面那条Standard Welcome里的 accept the answer 指的是啥吗?
Apr
8
reviewed Close Calculus with Mathematica, books, interesting examples
Apr
8
revised Combining Mandelbrot and Monte Carlo
added 2 characters in body
Apr
8
comment Compile, “global variables” and recursion
But this still calls MainEvaluate……
Apr
8
revised Combining Mandelbrot and Monte Carlo
added 82 characters in body
Apr
8
revised Combining Mandelbrot and Monte Carlo
Typo fixed.
Apr
8
answered Combining Mandelbrot and Monte Carlo
Apr
5
awarded  Announcer
Apr
5
comment How to speed up auxilary DoolittleDecomposite function?
Well, I'm not that familiar with the internal mechanism, either, but the Compile`GetElement trick does work, at least on my machine.
Apr
4
revised Bug report: Attempting to Save Selection As… in a magnified Notebook fails with errors
added 10 characters in body
Apr
4
comment How to speed up auxilary DoolittleDecomposite function?
For the reason why Compile`GetElement is fast, it's mentioned here that it turns off the bound check.
Apr
4
comment How to speed up auxilary DoolittleDecomposite function?
Maybe it's due to the compiler? I use TDM-GCC 4.8.1, with "CompileOptions"->"-Ofast", and this is my implementation: doolittleDecomposition2 = With[{g = Compile`GetElement}, Compile[{{a, _Real, 2}}, With[{n = Length[a]}, Module[{t = a}, Do[Do[Do[ t[[i, j]] -= g[t, i, k] g[t, k, j];, {k, 1, i - 1}];, {j, i, n}]; Do[Do[t[[j, i]] -= g[t, j, k] g[t, k, i];, {k, 1, i - 1}]; t[[j, i]] /= g[t, i, i];, {j, i + 1, n}];, {i, 1, n}]; t]], RuntimeOptions -> "Speed", CompilationTarget -> "C"]].
Apr
4
comment How to speed up auxilary DoolittleDecomposite function?
You can use Compile`GetElement to speed up doolittleDecomposition by a factor of 2. (See here for an example. )
Apr
3
awarded  Announcer
Apr
3
comment Backslide of Limit
@MichaelE2 Yeah, I know, I just feel obligated to remind all the people who take part in the discussion for the correctness of v8 :)
Apr
3
comment Backslide of Limit
@MichaelE2 I added a step-by-step proof, have a look.