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Jun
11
revised NIntegrate of surface area of intersecting spheres yields zero
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Jun
11
revised NIntegrate of surface area of intersecting spheres yields zero
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Jun
11
comment Numerical integration converging too slowly
...your integrand has very nearly the symmetry F[x, y]*G[x, y] == - F[x, 2 Pi-y]*G[x,2Pi -y] from which you can show that integral will be zero
Jun
11
answered NIntegrate of surface area of intersecting spheres yields zero
Jun
11
comment Numerical integration converging too slowly
It doesn't actually help in this case, but you should strive to keep your integrand a reasonable magnitude (it is order 10^60.. ). Factor out the constants so the integrand is just F[x,y]*G[x,y]/r (divide by r gets you order 1. ). That said I think your integral actually is zero or nearly so with approximately equal negative and positive parts.
Jun
10
comment NIntegrate of surface area of intersecting spheres yields zero
The area calculation fails because you are depending on the practically zero probability of NIntegrate's initial sampling happening to exactly hit a surface. Try to formulate it as an integral over the surface of each sphere, with a Boole test if the surface element is in the box.
Jun
10
comment Bessel functions and ListContourPlot
may be more a math.stackexchange.com question..
Jun
10
comment Bessel functions and ListContourPlot
My thinking is your hand plot is wrong, or I don't follow what it is you are plotting. The expression is zero for x=0, so you must get a zero contour line straight up the middle..
Jun
10
revised How to make a cumulative time plot?
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Jun
10
answered How to make a cumulative time plot?
Jun
10
comment How to make a cumulative time plot?
probably you need to convert to AbsoluteTime if you want to use Histogram. Do you want interval binning?
Jun
9
comment How to make a cumulative time plot?
I suspect you'll want to look up DateListPlot and MapIndexed
Jun
8
comment How much time for solving a system of equations?
It may help if you can add constraints to some of the parameters (based on your understanding of the actual problem, eg. I'd guess L>0 for example).. Also I would hand reduce as much as possible, eg, H,delt,db and a few other unknowns can be readily eliminated.
Jun
8
revised Convert mathematica math expression form to python math expression?
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Jun
8
comment Convert mathematica math expression form to python math expression?
I'm not sure what you mean by convert 1.. Do you want the floating 1. to appear as an integer?
Jun
8
revised Convert mathematica math expression form to python math expression?
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Jun
8
comment How much time should one give Mathematica for an integral evaluation?
The numeric and analytic cases are very different. NIntegrate might reasonably take a very long time just because the integrand evaluation takes a long time. As to analytic Integrate, I cant say I've seen it take more than an hour or so and come back with a useful result. If its important maybe let it chug away over night, but no longer than that..
Jun
8
revised Convert mathematica math expression form to python math expression?
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Jun
8
revised Convert mathematica math expression form to python math expression?
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Jun
8
answered Convert mathematica math expression form to python math expression?