Dynamic kernels

Required prerequisites

• Search the issue tracker to check if your feature has already been mentioned or rejected in other issues.

Describe the feature

One may need to either grow, reduce or change the structure of the kernel within an algorithm. The idea of inserting a gate in a specific location comes into play here without having to modify/ copy the kernel once again.

For example:

import cudaq 

@cudaq.kernel
def kernel():
    q = cudaq.qvector (3)
    x(q[0])

@cudaq.kernel
def dynamic_kernel(q1: cudaq.qubit, q2: cudaq.qubit):
    cx(q1, q2)
    
for i in range(n_epochs): 
    
    result = scipy.optimize(obj)
    
    if result < 1: 
        cudaq.insert(dynamic_kernel, kernel, position = 2) #insert dynamic kernel into kernel at position 2
    
    #need to think about what position 2 means in this case

No source files or tests are named. Start by reviewing the kernel entry points represented by @cudaq.kernel and cudaq.insert, then determine how dynamic insertion should work for the grow, reduce, and structural-change cases. Done means the feature's insertion-position semantics and supported kernel changes are defined and implemented with coverage for the shown workflow.