Hi Rita,
The error you get is because your retrieval pressure grid extends higher up than your atmospheric grid. Indeed, this error should be caught but I have to see with the others how this can be done most effectively. Regarding the covariance matrix: The covariance matrix contains 6 blocks because for each retrieval quantity, i.e. for O3, freq. shift, and Polyfit, two blocks are added. It's two because the inverses of the blocks are pre-computed and included in the covariance matrix. In Python, you can access the blocks of the covariance matrix over the 'blocks' attribute which contains one element for each retrieval quantity (their inverses are stored in the 'inverse_blocks' attribute). The matrix representation of each block can then be retrieved using its matrix attribute: sx = ws.covmat_sx.value matrix = sx.blocks[0].matrix Hope this helps! Best, Simon ________________________________ From: arts_users.mi-boun...@mailman.rrz.uni-hamburg.de <arts_users.mi-boun...@mailman.rrz.uni-hamburg.de> on behalf of Rita Kajtar <rita.kaj...@gmail.com> Sent: Tuesday, November 26, 2019 8:17:05 PM To: arts_users...@mailman.rrz.uni-hamburg.de Subject: [arts-users] atm.scenario & cov-mat issues Hello! I have a few questions, the first ones related to the issues I encounter when I try to use a subarctic atmospheric scenario with user-defined pressure and retrieval pressure grids (*), and the next questions related to what precisely does the covariance matrix that my ARTS file produces contain and how can one actually extract certain blocks out of it once one knows what it contains; the documentation on covmat_sx does not provide too much information on this (**) (*) ####################################################################################### - I am running an adapted version on TestOEM.arts and while the pressure grid and the pressure retrieval grid I set work well with the tropical atm. background that TestOEM.arts comes with, I get the following error when I try to use a subarctic-winter scenario: Run-time error in method: AtmFieldsCalc There is a problem with the grids for the following interpolation: Raw field to p_grid The minimum of the new grid must be inside the original grid. (We allow a bit of extrapolation, but not so much). Minimum of original grid: -2.3969 (0.091) Minimum allowed value for new grid: -2.7956 (0.0610782) Actual minimum of new grid: -2.81347 (0.0599964) - If I then replace the pressure grid with a 'shorter' one, so that I make sure I fall within the minimum allowed value of the grid, I hit an assertion: - xaStandard Assertion failed: (og_min <= tng), function gridpos, file /Users/mypath/arts/src/interpolation.cc, line 345. Abort trap: 6 (**) ###################################################################################### - Why for a simulation containing three retrieval species. i.e. O3, freq.shift and polyfit (no winds considered this time), the retrieval covariance matrix (Sx) contains six retrieval errors? and what are those representing? The terminal output shows a 17 x 17 sized covariance matrix, which corresponds to the 15 elem O3 array + 1 elem of freq-shift + 1 elem of polyfit. (covmat_sx attached) - I can import the generated covariance matrix in my Python code, but how can I extract the different blocks out of it for further use, i.e plotting? With best regards, Rita Kajtar
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