Hi Nikhil, In that case I would suggest using a more robust integrator, e.g. gsl_integration_cquad (disclaimer: I wrote this integrator myself), and doing the integral substitution yourself.
There are a number of different substitution functions that may be more or less well adapted to your problem. A good place to start is [1] which describes some different substitutions and their properties. Cheers, Pedro [1] http://www.math.ethz.ch/~waldvoge/Projects/nisJoerg.pdf On Tue, 2013-08-13 at 13:24 +0000, Nikhil wrote: > Hi Pedro, > > Thank you very much for your response. I got your point and why my > integration returns 0.0 (since the stretch/shrink factor in the > transformation goes as 1/t^2, higher patches on t will be stretched more) : > (. > > Increasing tolerance did not help in this case. I don't know what other > method could work. I have an integral, which is spread over a large span > along x-axis. > > regards, > Nikhil > >
