Good evening, I am using a modified version of the sample Penny Lane VQLS code in order to solve a system of PDE’s. In this case the state |b> will not be U = H1H2H3. I have been able to represent |b> as the result of a sum unitaries, with scalar coefficients. Similar to decomposing the A operat…

Hi @Dan_Velez and welcome to the Xanadu forum. It seems like you want to create an operation U that is the sum of a set of operations (e.g. something like 0.5*RY*CNOT + 1.3*RY*CY + ...), and you’re wondering how to add the coefficients (0.5, 1.3, etc. above)? Is this correct? I’m not sure how that…

Thank you. You understood the question perfectly. I have been playing with the idea of trying to implement an amplitude to the calling of U to prepare |b>, but I don’t think this works with the template cost function. And I think you are correct that I need to go back to basics to see how the deri…

[loss%20function] This seems to work now

Hi @Dan_Velez , Thank you very much for the update. We are glad to know your model seems to be working now. Let us know if there’s anything else we can help with. Regards.

Thanks. I believe there is a factor of 2 in the second term from the internal sum, which cancels the 2 in 1/(2n), but the basic form here should be correct

Thanks for sharing @Dan_Velez !

slight correction to formula… no d’s (or u’s) in the denominator (PSI norm)

Hi @Dan_Velez , could you please reshare the way you find out those gates and coefficients for the b vector? I found a way to do it for normalized vector in Qiskit but still struggling to find a way in Pennylane. Could you provide the approach or methods you used to find it here?

Hi @Dan_Velez Could you share me the overview am facing the same issue of decomposition of U in VQLS and which optimizer did you used to execute the program as am facing barren plateau issue

VQLS with non-trivial |b>

PennyLane Help

CatalinaAlbornoz November 26, 2021, 1:43am 10

Hi @sajal, was your answer to this thread what you needed to answer this question too? Or is this a different question?

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VQLS with non-trivial |b>

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