The following Matlab project contains the source code and Matlab examples used for impulse response invariant discretization of distributed order low pass filter.  irid_dolpf function is prepared to compute a discrete-time finite dimensional (z) transfer function to approximate a distributed order integrator ((c^r)/(b-a))*int(1/(s+c)^r,r,a,b), where "s" is the Laplace transform variable.