PennyLaneAI / PennyLaneAI/catalyst
Print function ordering
Open
Nobody has claimed this yet.
bug
- Dominant language
- Python
- Stars
- 234
- Forks
- 84
- Avg merge
- 2d 15h
- Merged PRs (30d)
- 66
Description
The print function should not be re-ordered. Example:
import pennylane as qml
from catalyst import debug, grad, measure, qjit
@qml.qnode(qml.device("lightning.qubit", wires=20))
def f(x):
qml.RX(x, wires=[0])
debug.print("hello")
return qml.state()
@qjit(keep_intermediate=True, verbose=True)
def foo(x):
y = f(x)
debug.print("world")
return y
print(foo(1.0))
Produces the following incorrect MLIR
module @foo {
func.func public @jit_foo(%arg0: tensor<f64>) -> tensor<1048576xcomplex<f64>> attributes {llvm.emit_c_interface} {
%0 = call @f(%arg0) : (tensor<f64>) -> tensor<1048576xcomplex<f64>>
"catalyst.print"() {const_val = "world"} : () -> ()
return %0 : tensor<1048576xcomplex<f64>>
}
func.func private @f(%arg0: tensor<f64>) -> tensor<1048576xcomplex<f64>> attributes {diff_method = "parameter-shift", llvm.linkage = #llvm.linkage<internal>, qnode} {
"catalyst.print"() {const_val = "hello"} : () -> ()
quantum.device["/home/erick.ochoalopez/Code/cataliist/frontend/catalyst/utils/../../../runtime/build/lib/librtd_lightning.so", "LightningSimulator", "{'shots': 0, 'mcmc': False}"]
%0 = stablehlo.constant dense<20> : tensor<i64>
Notice that the first statement of the qnode is the print statement as opposed to any other.
The correct MLIR would have the print statement after the RX operation.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the provided Python example and inspect its generated MLIR, focusing on how catalyst.print operations are ordered relative to the RX operation and qnode calls. Done means the generated MLIR preserves source order, with "hello" emitted after RX and "world" after the qnode call.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100