Creating custom node types for geometry nodes

Question

is it possible to create custom nodes for the geometry node editor (NOT node groups, combining blender built-in nodes), define inputs and outputs and execute some python code in between? I couldn't find any information about completely userdefined nodes nor tutorials anywhere.

Further information about the usecase:

I want to create a node, which executes a more elaborate python code involving some linear algebra and finding eigenvalues of matrices. Therefore I created a python code using scipy, installed the scipy package in blender and I am already able to execute it within blender in the scripting environment and it outputs the correct values in the system console. Now I want to take the input values from a geometry node (position in x and y), calculate the output value of my python function and assign it as a z coordinate to all my verticies.

Answer 1

I've found this method:

import bpy
from bpy.types import Node, NodeSocket

class MyCustomNode(Node):
    '''This is a custom node that multiplies two inputs and outputs the result.'''

    bl_idname = 'CustomNodeType' # Unique identifier for your node type
    bl_label = 'My Custom Node' # Display name for your node

    # Define the input and output sockets for your node
    my_input_1 : NodeSocket
    my_input_2 : NodeSocket
    my_output : NodeSocket

    def init(self, context):
        # This method is called when the node is created
        self.inputs.new('NodeSocketFloat', 'Input 1')
        self.inputs.new('NodeSocketFloat', 'Input 2')
        self.outputs.new('NodeSocketFloat', 'Output')
    
    def update(self):
        # This method is called when the node updates
        self.outputs[0].default_value = self.inputs[0].default_value * self.inputs[1].default_value

# Register your node type with Blender
bpy.utils.register_class(MyCustomNode)

Simply execute the script, then add it to your nodes:

I was searching too, I'm just testing to go further...
Blender v3.4.1 - It's now possible -