Date: Nov 20, 2012 3:53 AM
Author: Bharat
Subject: Warning during integration: Matrix is close to singular or badly scaled

I have multiple doubts in this regard. 

My system components are best represented as matrices (three coupled components in a physical unit which interact with different neighboring units [an array of units]).

But to pass it to an ODE solver I need vectorize the output of the odefun. This also requires me to convert y that is passed to odefun into a matrix. The vector size comes to ~1800.
I was using ode23s with RelTol = 1e-5 and AbsTol = 1e-6

With a computer config of 8-core 2GHz processor and 6GB RAM the equation is taking a long time to solve and the solver starts giving a warning "Matrix is close to singular or badly scaled". The solution is also not in the expected range.

I have the following doubts:

1. Which ode solver to use (i was thinking of using 113 because I dont expect the system to be very stiff along with setting NonNegative on)

2. Will quadv be a better option

3. Is there any other way to reduce computation time