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bio website math.upatras.gr/~spawn
location Brazil
age 37
visits member for 2 years, 2 months
seen Mar 21 at 14:49

Mathematics, PDEs, General Relativity and symbolic programming with Mathematica.


May
9
comment Numerically solve 2nd order differential equation with singularity
I see, the think is that if you can use the transformation $Y(S)=\int F(s)\, ds,\ S= \frac{F(s)}{y}$ where $F$ a solution of the ODE you can reduce its order by one. But this is a reduction for this ODE and don't know if can be applied to your actual problem.
May
9
comment Numerically solve 2nd order differential equation with singularity
Do you know any special solution of this ODE?
May
8
comment Solve for the intersection point of 3 surfaces
If you want to turn them into the form $f_i(x,y,z)=0$ try using Eliminate.
May
8
comment Solve for the intersection point of 3 surfaces
@bills use ParametricPlot3D
May
7
revised Symbolic manipulation of functional form
added 134 characters in body
May
7
revised Symbolic manipulation of functional form
added 4 characters in body
May
7
answered Symbolic manipulation of functional form
May
7
comment Symbolic manipulation of functional form
Take the Jacobian, zero everything as for the constant term just zero everything in the initial expression.
May
3
awarded  Enthusiast
May
1
comment Why does this simple program leak memory?
Have you tried inserting $HistoryLength=0 inside ParallelMap like ParallelMap[$HistoryLength=0;Export...]
May
1
comment Why does this simple program leak memory?
Have you tried removing the set of data used on every export? Something like data[[#]]={}?
Apr
30
comment Extracting sequences from a list?
@b.gatessucks yes the correct structure of the pattern will depend on the actual data, if the tags contain also in the data strings the OP should exclude just the xml tags. My opinion is that the XMLObject and XMLElement objects must be exploited instead of a flattened list.
Apr
30
comment Extracting sequences from a list?
If you don't Flatten the data from the xml Case will be a good alternative.
Apr
30
answered Extracting sequences from a list?
Apr
29
comment List plot 3D not showing correct data
@soandos if you check the manual you will see that you gave him to make the 3D plot of an array of height values.
Apr
29
comment List plot 3D not showing correct data
In your data you give four elements $\{\{a_1,b_1,c_1,d_1\},...\}$ what's the last one for?
Apr
29
comment iterate method to find roots
@Keith use Most. Also check again the list its impossible to have such an expression [0,1,30].
Apr
29
answered iterate method to find roots
Apr
28
comment Plot derivative of integral with changing limits
When it's just a formula ($t^2$) or you give a function ($f(x)$) to name a few.
Apr
28
comment Plot derivative of integral with changing limits
If you check Plot's Attributes you will see that has the HoldAll attribute, hence the expression will remain unevaluated.