changing multiple parameters in parameterized model in OpenLCA-IPC 2.0

Question

Dear all,

I am referring to a question Parameterized calculation setups in python - ask.openLCA - Question and Answer (Q&A) on Life Cycle Assessment (LCA) - A Life Cycle Assessment (LCA) Community in 2020, which matches my needs, but I think there is a change in syntax between OpenLCA 1.x and 2.x.

I have a parametrized model in my database, want to change the parameters via the ParameterReDef and run the calculation by a phyton script. In the documentation there is an example for the redefinition of one parameter. I have adapted the code to my needs to cover this issue but I am not sure if this is the right way.

myPSystem=client.get_descriptors(schema.ProductSystem, "36db6ce6-5575-410d-9933-ecfb66db35f0")

myPSystem_par=client.get_parameters(schema.ProductSystem,"36db6ce6-5575-410d-9933-ecfb66db35f0")

 

# Ansteuern des IPC Servers

setup = schema.CalculationSetup(

        target=myPSystem,

        impact_method=schema.Ref(id="c45bb4f6-8b50-425f-a4f6-c69668d7ac96"),

        parameters=[schema.ParameterRedef(name=myPSystem_par[1].name, value=4000,context=myPSystem_par[1].context),

                    schema.ParameterRedef(name=myPSystem_par[2].name, value=250,context=myPSystem_par[1].context)],

amount=inputs["fnctionalunit"])

Kind regards,

Dieter

Answer 1

Hi Dieter,

This is the way to do it indeed. Be careful, the context of the second parameter redefinition might be wrong as you are using the index 1 and not 2.

Is something not working?

Regards,

François

Comments

Thanks for your fast confirmation! I really was not sure if it is right or wrong (i was confused by the post of 2020). The first parameter on position 0 is a global one which I don´t need so start number will be 1 and ascending.

Kind regards,
Dieter

---

Hello,
I tried to implement a similar application. However, I cannot get the ParameterRedef method to work.
Here is a snippet of my code:

myPSystem = client.get_descriptors(schema.ProductSystem)  # I had to get rid of the UUID as it raised an error (2 arguments expected, 3 given)
myPSystem_par = client.get_parameters(schema.ProductSystem, "bb62617b-6bc3-46a6-b7a3-100574780b1b")

bsp_liste = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]

for i in range(len(myPSystem_par)):
    print(bsp_liste[i])
    print(f"Parameter Name: {myPSystem_par[i].name}, Value: {myPSystem_par[i].value}, Context: {myPSystem_par[i].context}")
    # myPSystem_par[i].value = float(bsp_liste[i])
    schema.ParameterRedef(name=myPSystem_par[i].name, value=float(bsp_liste[i]), context=myPSystem_par[i].context)
    print(f"Parameter Name: {myPSystem_par[i].name}, Value: {myPSystem_par[i].value}, Context: {myPSystem_par[i].context}")

The code should display the names and values of the parameters within the product system, then change the values and display the new values. Instead, I get the same result twice (so no redefinition is being done). I also tried to change only one value (so no for loop), but it didn’t work either.

Has anyone else encountered a similar issue and could help me out?

Thanks in advance!

Regards,

Armando