Meep模块调用get_GDSII_prisms传入自定义函数触发OverflowError问题求助

Let me break down what's happening here and how to fix it:

The error you're seeing (OverflowError: in method 'get_GDSII_prisms', argument 3 of type 'int') is a bit misleading—it's not that your third parameter (UPPER_BRANCH_LAYER) is invalid, but rather a side effect of a mismatch in the signature of your custom medium function.

Why This Happens #

Older versions of Meep require custom medium functions (passed to get_GDSII_prisms instead of a mp.Medium instance) to accept three separate float arguments: x, y, and z (the coordinates of the point being evaluated). When you pass a function that only accepts a single mp.Vector3 parameter, the Python-C binding layer gets confused about how to map arguments to the underlying C++ function. This confusion leads to incorrect parameter parsing, which manifests as an overflow error tied to the third argument.

Solution 1: Adjust Your Function Signature #

Modify your test function to accept three individual coordinates instead of a single vector:

gdsII_file = 'coupler.gds'
UPPER_BRANCH_LAYER = 31
si_zmax = 10
si_zmin = -10

def test(x, y, z):
    return mp.Medium(index=15)

upper_branch = mp.get_GDSII_prisms(test, gdsII_file, UPPER_BRANCH_LAYER, si_zmin, si_zmax)

You can also use a lambda for brevity:

upper_branch = mp.get_GDSII_prisms(lambda x,y,z: mp.Medium(index=15), gdsII_file, UPPER_BRANCH_LAYER, si_zmin, si_zmax)

Solution 2: Upgrade Meep to the Latest Version #

Newer Meep releases support medium functions that take a single mp.Vector3 parameter (which is what you originally tried). If you want to keep your original function signature, upgrade Meep using pip:

pip install --upgrade meep

After upgrading, your original single-parameter function should work as expected.

Quick Validation Checks #

To rule out other issues:

• Confirm UPPER_BRANCH_LAYER is indeed an integer (your code shows 31, which is valid)
• Ensure your GDSII file path is correct and the file is accessible
• Verify si_zmin and si_zmax are numeric values (int/float are both fine)

内容的提问来源于stack exchange，提问作者solenec08