Matlab for General FIR Filter Design

The cfirpm function (formerly cremez) [116,117] in the Matlab Signal Processing Toolbox performs complex $\ensuremath{L_\infty}$ FIR filter design (``Complex FIR Parks-McClellan''). Convergence is theoretically guaranteed for arbitrary magnitude and phase specifications versus frequency. It reduces to Parks-McClellan algorithm (Remez second algorithm) as a special case.

The firgr function (formerly gremez) in the Matlab Filter Design Toolbox performs ``generalized'' $\ensuremath{L_\infty}$ FIR filter design, adding support for minimum-phase FIR filter design, among other features [254].

Finally, the fircband function in the Matlab DSP System Toolbox designs a variety of real FIR filters with various filter-types and constraints supported.

This is of course only a small sampling of what is available. See, e.g., the Matlab documentation on its various toolboxes relevant to filter design (especially the Signal Processing and Filter Design toolboxes) for much more.