9/19/2023 0 Comments Matlab r2012b fortran compiler![]() * Do not free A, since the output plhs points to A */įirst setup the mex compiler. * to solve the Volterra equation as A*x = f Ncols = mrows /* not really useful here */ĭouble *A = mxCalloc(mrows*ncols, sizeof(double)) Mrows = mxGetM(prhs) /* get its length */ MexFunction(int nlhs,mxArray *plhs,int nrhs,const mxArray *prhs)ĭouble *f /* the pointer to the vector f */ĭouble h /* timestep in the discretization */į = mxGetPr(prhs) /* assign the pointer to the 1D array */ Void voltmat( double *A, double *f, double h, mwSize m, mwSize n ) * voltmat takes an array of doubles f, a double h, and returns a matrix A */ * always include mex.h, it contains the Matlab types */ * f: column vector of doubles of length m * VOLTMAT_MEX generates a Volterra matrix from the vector f $$t_i = i h, i = 0,1.,N, h = \frac The full C source code type voltmat_mex.c We use the trapezoidal rule to discretize the integral term Solving the Volterra equation numerically Where $b(t)$ is the birth rate at time $t$ needed for keeping the population constant in a population with instantaneous death rate of individuals aged $a$, $f(a)$. The Volterra type II equation is a renewal equation Second example: The sum of the first N integers.Second implementation: MEX file (C source code). ![]() Solving the Volterra equation numerically.
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