What is the difference between PML, UPML, CPML?
I know only PML do you think is it enough to solve all type of FDTD problem?
dont know
Hi,
PML is perfectly matched layer in wich we divide the electric and magnetic field to two components for Example Ex to EX+ and EX-.
UPML uniaxial perfectly matched layer avoid this splitting and use the standard FDTD formaulation. so it easy to understand and to implement.
CPML conformal PML is for curved objects.
thank you helio1972,but I saw some refference book which use PML to solve all type of problem.
Hi,
Can you tell us what that book name is..?
Kanjeero
hi helio
u do usually good works
a3anaka *****
Hi,
A correction.
CPML is Convolutional PML (not Conformal PML) and has to do nothing extra with curved objects. It is Conformal FDTD wich will treat curved objects in a special way.
The advantage with CPML is that it's memory requirement is less compared to UPMl or split field PML (Berenger PML).
All these concepts are explained in Taflove's book 3rd edition, chapter 7). This book can be downloaded from the e book download section
Best Regards
Jithesh
Actually that is not quite true. Berenger published some lecture notes:
Perfectly Matched Layer (PML) for Computational Electromagnetics
where he compared PML, UPML, CPML, NPML and there CPML did not come out on top. What CPML is good at is allowing arbitrary materials (e.g. dispersive materials) to be included into the boundary. It is also a bit easier to code than PML. (although personally I think UPML is the easiest).
CPML only requires less memory if you do not choose to allocate memory for the boundaries separately.
To answer the first posters question: use PML unless either
1) you need to have different materials in the boundary (PML can be adjusted to include things like outgoing wires)
2) you need very good absorption and are willing to study the details of the CPML, there are several parameters you can adjust to improve things like late time reflections
If PML is not sufficient than you have to study the alternatives (UPML, CPML and NPML) in a bit more detail. I prefer Berenger's lecture notes to Taflove's 3rd edition but I do not recall seeing any code in the lecture notes.