How to create random dynamic 2D arrays in SystemVerilog?

问题

I know how to create a random dynamic array in SystemVerilog:

class packet;
    rand int unsigned len;
    rand byte data[];

    constraint size_con {
        len < 2000;
        data.size = len;
    }
endclass: packet

but I can't figure out how to use random 2d dynamic array?

class video_frame;
    rand int unsigned width;
    rand int unsigned height;
    rand int unsigned data[][];

    constraint size_con {
        width >= 8;
        width <= 4096;
        height >= 8;
        height >= 2048;
        // How to constraint data.size to be [height, width]
    }
endclass: video_frame;

回答1:

You need to realize that SystemVerilog has arrays of arrays which are not the same as multi-dimensional arrays. This means you have a dynamic array where each element is another dynamic array. So you need to constrain the size of each element.

   constraint size_con {
        width  inside {[8:4096]};
        height inside {[8:2048]};
        data.size == width;
        foreach (data[ii]) data[ii].size == height;
    }

来源：https://stackoverflow.com/questions/40724326/how-to-create-random-dynamic-2d-arrays-in-systemverilog