RE: numerical integration
- To: mathgroup at smc.vnet.net
- Subject: [mg40590] RE: [mg40536] numerical integration
- From: "David Park" <djmp at earthlink.net>
- Date: Thu, 10 Apr 2003 03:43:44 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
There seems to be an error in the typing of your data. You have a square
bracket instead of a curly bracket. Did you copy and paste it from your
notebook? In any case, I repeat it here.
data = {{0, 4.308115176}, {180, 11.83807029}, {320, 9.819597477}, {380,
9.003587475}, {420, 9.646700866}, {540, 9.003587475}, {660,
8.601966768}, {720, 8.090496405}, {780, 7.49290292}, {900,
7.536283436}, {1020, 7.086922454}, {1080, 6.876137912}, {1140,
6.580371983}, {1200, 6.430040607}, {1320, 6.300111915}, {1380,
6.077755024}, {1500, 6.101258682}, {1680, 5.96360292}, {1800,
5.821356082}};
ListPlot[data, PlotJoined -> True,
PlotRange -> All];
Needs["NumericalMath`NIntegrateInterpolatingFunct`"]
First make an interpolating function for the data. I used a first order
interpolation. You might want some other choice.
f = Interpolation[data, InterpolationOrder -> 1]
InterpolatingFunction[{{0., 1800.}}, "<>"]
NIntegrateInterpolatingFunction[f[x], {x, 0, 1800}]
13701.4
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: C B [mailto:cbhat at purdue.edu]
To: mathgroup at smc.vnet.net
I have data which looks like ..
data = {{0,4.308115176},{180,11.83807029},{320,9.819597477},{380,
9.003587475},{420,9.646700866},{540,9.003587475},{660,
8.601966768},{720,8.090496405},{780,7.49290292},{900,7.536283436},{1020,7.08
6922454},{1080,6.876137912},{1140,
6.580371983},[1200,6.430040607},{1320,6.300111915},{1380,
6.077755024},{1500,6.101258682},{1680,5.96360292},{1800,5.821356082}}
X value is time (sec)
Y value is gas readings
I could plot the XY plot but I need to get area under the curve. For that I
tried
<<NumericalMath`NIntegrateInterpolatingFunct`
Interpolation
NIntegrateInterpolatingFunction
But I am just not being able to figure out the exact sytax. Does anyone have
any experience with this kind of problem?