Hi Eric, My approach to this would be, using current PDL (2.080), in multiple stages:
* Read the data into a matrix ($m) with columns (freq,m11,a11,etc) as you seem to have already done (although you haven’t shown any code or real-but-minimal sample data which limits how much help people can provide) * Slice out the complex data, e.g. $c = $m->slice(‘1:-1’) so it’s columns (m11,a11,etc) * Reshape that with splitdim: $reshaped = $c->splitdim(0, 2) so columns (mag,angle) * Convert the polar format to rectangular: $angrad = $reshaped->slice(1) * $PDL::Transform::DEG2RAD; $rect = $reshaped->slice(0) * $angrad->cos->append($angrad->sin) so columns (real,imag) (your formula seems to not multiply the real by the magnitude which looks to me wrong) * Convert that to cdouble: $cd = czip($rect->mv(0,-1)->dog) giving row vector of cdouble * Reshape that with splitdim: $m22 = $cd->splitdim(0,4)->splitdim(0,2) giving (2,2,n) where n is number of original rows (this might need transposing given your data is column-major – if you leave it column-major like Fortran, make sure your docs are VERY CLEAR about that since PDL’s idiom is 0th dim is columns) Best regards, Ed From: Eric Wheeler<mailto:p...@lists.ewheeler.net> Sent: 01 July 2022 08:36 To: pdl-general@lists.sourceforge.net<mailto:pdl-general@lists.sourceforge.net> Subject: [Pdl-general] How do you create a set of cdouble matrices from (real, imag) values? Hello all, I'm trying to read RF touchstone (.s2p) files that are in a format like so: Freq(MHz) MagS11 AngS11 MagS21 AngS21 MagS12 AngS12 MagS22 AngS22 100 0.588 50.208 0.770 -35.964 0.770 -35.964 0.588 50.208 ... 200 0.589 51.209 1.771 -34.965 1.771 -34.965 1.589 51.209 There are thousands of these lines in a file, one line for each measured frequency. Each line represents a complex scattering (S-parameter) matrix and the mag/angle format needs to be converted to a `cdouble` to work on the matrix mathematically. A single-line 2x2 complex matrix might look as follows, where S_ji is a complex value: [ S11 S12 ] [ S21 S22 ] Since we are provided values in magnitude-angle format (in this example) they must be converted to cdoubles so we can work on them. There are several formats: RI, DB, and MA. For the MA (mag-angle) format this is the transform where $a is mag and $b is angle: $complex = cos($b*pi()/180) + $a*sin($b*pi()/180) * i I can generate a vector of 2x4 matrices holding mag-angle pairs by reading the file line by line like this: [ [ [ S11mag S11ang S12mag S12ang ] [ S21mag S21ang S22mag S22ang ] ] ... for each line ] I'm new to using PDL and at this point I'm not sure how to convert them to a computable form. Since the mag/angle values need to be manipulated in parallel before creating a cdouble out of them I'm not sure how to go about this. Here are my questions: 1. How can I efficiently apply the real = cos($b*pi()/180) imag = $a*sin($b*pi()/180) transform to each mag/angle pair where $a is mag and $b is angle? 2. How can I then (or simultaneously) convert the 2x4 real-imag matrix from #1 into a 2x2 cdouble matrix to look something like this? [ [ [ S11 S12 ] [ S21 S22 ] ] ... for each line where Sji are cdoubles ] 3. Now that I've described the issue, is there a better way to do this? Once they are in a matrix format then PDL can convert them efficiently to other matrix types (T, A, Z, Y) to create parallel or series circuits with matrix arithmetic at each frequency. We can then optimize the RF filter circuits using component models published by manufacturers from actual measurements. The resulting open-source tool will be comprised of Perl modules from this work and published on CPAN. Thanks for your help! -- Eric Wheeler KJ7LNW _______________________________________________ pdl-general mailing list pdl-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pdl-general
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