lsqnonneg Solves nonnegative least-squares curve fitting problems. xopt = lsqnonneg(C,d) xopt = lsqnonneg(C,d,param) [xopt,resnorm,residual,exitflag,output,lambda] = lsqnonneg( ... ) C : a matrix of doubles, represents the multiplier of the solution x in the expression C*x - d. C is M-by-N, where M is the number of equations, and N is the number of elements of x. d : a vector of doubles, represents the additive constant term in the expression C*x - d. d is M-by-1, where M is the number of equations. xopt : a vector of doubles, the computed solution of the optimization problem. resnorm : a double, objective value returned as the scalar value norm(C*x-d)^2. residual : a vector of doubles, solution residuals returned as the vector C*x-d. exitflag : Integer identifying the reason the algorithm terminated. output : Structure containing information about the optimization. Right now it contains number of iteration. lambda : Structure containing the Lagrange multipliers at the solution x (separated by constraint type).It contains lower, upper and linear equality, inequality constraints. Solves nonnegative least-squares curve fitting problems specified by : \begin{eqnarray} &\mbox{min}_{x} & 1/2||C*x - d||_2^2 \\ & & x \geq 0 \\ \end{eqnarray} We are calling IPOpt for solving the nonnegative least-squares curve fitting problems, IPOpt is a library written in C++. Harpreet Singh