NIntegrate with variable region
- To: mathgroup at smc.vnet.net
- Subject: [mg6254] NIntegrate with variable region
- From: Zvi Wiener <mswiener at pluto.mscc.huji.ac.il>
- Date: Mon, 3 Mar 1997 01:29:07 -0500
- Organization: Hebrew University of Jerusalem
- Sender: owner-wri-mathgroup at wolfram.com
Dear Mathematica users,
I wish to take an indefinite integral of a piecewise
continuous function. For example:
f[x_]:= Which[ x<0, 0, x<1, 1, x>=1, x];
I have a much more complicated function which depends on parameters,
but this example can demonstrate the problem.
I tried:
lst = {-1,0,1,2};
NIntegrate[ f[x], Prepend[lst,x]]
But the result was:
NIntegrate::vars:
Integration range specification Prepend[lst, x]
is not of the form {x, xmin, ..., xmax}.
NIntegrate[f[x], Prepend[lst, x]]
I have found a solution which I hardly understand, but it works.
NIntegrate[ f[x],##]&@@{Prepend[lst, x]}
Out[71]= 2.5
(Mathematica 3.0 with Windows 95)
Can anybody explain to me why the first way did not work.
I have a situation when the upper limit of integration is a
variable and must be choosen automatically but then I have
to adjust the region of integration since for different values of
the upper limit there is a different number of singularities in the
region.
Zvi Wiener.
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Zvi Wiener Business School
e-mail: mswiener at pluto.mscc.huji.ac.il Hebrew University
office: 972-2-588-3049 Mount Scopus
fax: 972-2-588-1341 Jerusalem 91905
http://pluto.huji.ac.il/~mswiener/zvi.html ISRAEL
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