# Error in phase processing **URL:** \ **Category:** Corrections/Data Quality\ **Tags:** py-art\ **Created:** [October 14, 2023, 11:45am UTC](https://openradar.discourse.group/t/error-in-phase-processing/329 "2023-10-14T11:45:16Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Jagdish\_jena](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@Jagdish\_jena](https://openradar.discourse.group/u/Jagdish_jena)\ **Post date:** [October 14, 2023, 11:45am UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/1 "2023-10-14T11:45:16Z")
I am using a C band radar with radar fields [‘DBZ’, ‘PHIDP’, ‘RHOHV’, ‘VEL’, ‘WIDTH’, ‘ZDR’] for phase processing i was using this code phidp, kdp = pyart.correct.phase\_proc\_lp(radar, 0.0,refl\_field=‘DBZ’,phidp\_field=‘PHIDP’,rhv\_field=‘RHOHV’,ncp\_field=‘RHOHV’ ,LP\_solver = “cvxopt”,debug=True) error : Cell In[4], line 6 1 # the next line force only the first sweep to be processed, this 2 # significantly speeds up the calculation but should be commented out 3 # in production so that the entire volume is processed 4 radar.sweep\_start\_ray\_index[‘data’] = np.array([0]) ----\> 6 phidp, kdp = pyart.correct.phase\_proc\_lp(radar, 0.0,refl\_field=‘DBZ’,phidp\_field=‘PHIDP’,rhv\_field=‘RHOHV’,ncp\_field=‘RHOHV’ ,LP\_solver = “cvxopt”,debug=True) 8 radar.add\_field(‘proc\_dp\_phase\_shift’, phidp) 9 radar.add\_field(‘recalculated\_diff\_phase’, kdp) File ~\anaconda3\Lib\site-packages\pyart\correct\phase\_proc.py:1196, in phase\_proc\_lp(radar, offset, debug, self\_const, low\_z, high\_z, min\_phidp, min\_ncp, min\_rhv, fzl, sys\_phase, overide\_sys\_phase, nowrap, really\_verbose, LP\_solver, refl\_field, ncp\_field, rhv\_field, phidp\_field, kdp\_field, unf\_field, window\_len, proc, coef) 1192 mysoln = LP\_solver\_pyglpk( 1193 A\_Matrix, B\_vectors, nw, really\_verbose=really\_verbose 1194 ) 1195 elif LP\_solver == “cvxopt”: → 1196 mysoln = LP\_solver\_cvxopt(A\_Matrix, B\_vectors, nw) 1197 elif LP\_solver == “cylp”: 1198 mysoln = LP\_solver\_cylp( 1199 A\_Matrix, B\_vectors, nw, really\_verbose=really\_verbose 1200 ) File ~\anaconda3\Lib\site-packages\pyart\correct\phase\_proc.py:720, in LP\_solver\_cvxopt(A\_Matrix, B\_vectors, weights, solver) 718 this\_soln = np.zeros(n\_gates) 719 for i in range(n\_gates): → 720 this\_soln[i] = sol[“x”][i + n\_gates] 722 # apply smoothing filter and record in output array 723 mysoln[raynum, :] = smooth\_and\_trim(this\_soln, window\_len=5, window=“sg\_smooth”) TypeError: ‘NoneType’ object is not subscriptable if anyone has insights on how to solve this I would greatly appreciate your guidance ---
**Author:** ![mgrover1](https://yyz2.discourse-cdn.com/free1/user_avatar/openradar.discourse.group/mgrover1/32/7_2.png) [@mgrover1](https://openradar.discourse.group/u/mgrover1)\ **Post date:** [October 17, 2023, 4:22pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/2 "2023-10-17T16:22:48Z")
Could you run ```bash conda list ``` and post the output so we can have an idea of what versions you have installed? Also, which data file is this? ---
**Author:** ![Jagdish\_jena](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@Jagdish\_jena](https://openradar.discourse.group/u/Jagdish_jena)\ **Post date:** [October 17, 2023, 7:53pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/3 "2023-10-17T19:53:01Z")
![conda list](https://global.discourse-cdn.com/free1/uploads/openradar/original/1X/02c22083b56097b9abeabdd2f71fa5cafbf47c94.jpeg) data file is from Thumba DWR data which is processed by me . i have attched a sample file below. > **[RCTLS\_13MAY2018\_135449\_L2B\_STD.nc](https://drive.google.com/file/d/185r7_AHQzav7W3iVXnXD-xsR0Ytfdi7N/view?usp=sharing)** > > Google Drive file. ---
**Author:** ![mgrover1](https://yyz2.discourse-cdn.com/free1/user_avatar/openradar.discourse.group/mgrover1/32/7_2.png) [@mgrover1](https://openradar.discourse.group/u/mgrover1)\ **Post date:** [October 18, 2023, 1:41pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/4 "2023-10-18T13:41:15Z")
Which version of Py-ART are you running? The screenshot cuts off in the b portion of the packages. I tested this on the latest version Py-ART, and it ran successfully: ```python import pyart # Read in the radar data radar = pyart.io.read("RCTLS_13MAY2018_135449_L2B_STD.nc") # Apply the phase processing phidp, kdp = pyart.correct.phase_proc_lp(radar, 0.0, refl_field="DBZ", phidp_field="PHIDP", rhv_field="RHOHV", ncp_field="RHOHV", LP_solver = "cvxopt", debug=True) Unfolding /Users/mgrover/git_repos/pyart/pyart/correct/phase_proc.py:177: RuntimeWarning: invalid value encountered in divide return abs(signal) / _noise Exec time: 2.717604875564575 Doing 0 GLPK Simplex Optimizer 5.0 Doing 1 6526 rows, 2612 columns, 13038 non-zeros 0: obj = 0.000000000e+00 inf = 1.071e+04 (2606) 6322: obj = 1.739944370e+05 inf = 7.283e-14 (0) 60 * 6500: obj = 1.722717219e+05 inf = 9.104e-15 (0) 2 OPTIMAL LP SOLUTION FOUND GLPK Simplex Optimizer 5.0 5021 rows, 2010 columns, 10028 non-zeros 0: obj = 0.000000000e+00 inf = 1.472e+04 (2004) Perturbing LP to avoid stalling [3618]... 4415: obj = 3.303218515e+03 inf = 1.965e-06 (0) 42 Removing LP perturbation [5042]... * 5042: obj = 1.192051355e+03 inf = 1.315e-13 (0) 6 OPTIMAL LP SOLUTION FOUND Doing 2 GLPK Simplex Optimizer 5.0 3251 rows, 1302 columns, 6488 non-zeros Doing 0: obj = 0.000000000e+00 inf = 9.807e+03 (1296) Perturbing LP to avoid stalling [1663]... 2239: obj = 1.739060931e+03 inf = 2.646e-09 (0) 20 Removing LP perturbation [2684]... * 2684: obj = 3.778228050e+02 inf = 1.972e-13 (0) 4 OPTIMAL LP SOLUTION FOUND 3 GLPK Simplex Optimizer 5.0 2336 rows, 936 columns, 4658 non-zeros Doing 4 0: obj = 0.000000000e+00 inf = 6.854e+03 (930) 1833: obj = 4.101107728e+02 inf = 7.105e-14 (0) 17 * 2050: obj = 2.530848447e+02 inf = 8.384e-13 (0) 2 OPTIMAL LP SOLUTION FOUND GLPK Simplex Optimizer 5.0 1806 rows, 724 columns, 3598 non-zeros 0: obj = 0.000000000e+00 inf = 5.127e+03 (718) 1166: obj = 3.333312791e+02 inf = 0.000e+00 (0) 10 * 1341: obj = 1.760857907e+02 inf = 2.194e-13 (0) 1 OPTIMAL LP SOLUTION FOUND Doing 5 GLPK Simplex Optimizer 5.0 1061 rows, 426 columns, 2108 non-zeros Doing 6 0: obj = 0.000000000e+00 inf = 2.693e+03 (420) 740: obj = 1.975207042e+02 inf = 1.315e-13 (0) 6 * 817: obj = 1.008230690e+02 inf = 4.619e-14 (0) 1 OPTIMAL LP SOLUTION FOUND GLPK Simplex Optimizer 5.0 831 rows, 334 columns, 1648 non-zeros Doing 7 0: obj = 0.000000000e+00 inf = 1.950e+03 (328) 512: obj = 1.378641183e+02 inf = 5.329e-15 (0) 4 * 604: obj = 6.297361663e+01 inf = 5.151e-14 (0) 1 OPTIMAL LP SOLUTION FOUND GLPK Simplex Optimizer 5.0 626 rows, 252 columns, 1238 non-zeros Doing 8 0: obj = 0.000000000e+00 inf = 1.351e+03 (246) 377: obj = 1.071771379e+02 inf = 1.427e-14 (0) 3 * 429: obj = 5.187844123e+01 inf = 5.063e-14 (0) OPTIMAL LP SOLUTION FOUND GLPK Simplex Optimizer 5.0 501 rows, 202 columns, 988 non-zeros Doing 9 0: obj = 0.000000000e+00 inf = 9.900e+02 (196) 309: obj = 8.190416547e+01 inf = 2.320e-14 (0) 2 * 355: obj = 4.393185547e+01 inf = 1.954e-14 (0) 1 OPTIMAL LP SOLUTION FOUND Doing 10 GLPK Simplex Optimizer 5.0 421 rows, 170 columns, 828 non-zeros 0: obj = 0.000000000e+00 inf = 7.649e+02 (164) 234: obj = 7.688575510e+01 inf = 3.553e-15 (0) 1 * 274: obj = 4.094557344e+01 inf = 3.375e-14 (0) 1 OPTIMAL LP SOLUTION FOUND GLPK Simplex Optimizer 5.0 361 rows, 146 columns, 708 non-zeros 0: obj = 0.000000000e+00 inf = 6.059e+02 (140) 203: obj = 7.842866003e+01 inf = 3.553e-15 (0) 1 * 243: obj = 3.780782667e+01 inf = 0.000e+00 (0) 1 OPTIMAL LP SOLUTION FOUND ``` ---
**Author:** ![mgrover1](https://yyz2.discourse-cdn.com/free1/user_avatar/openradar.discourse.group/mgrover1/32/7_2.png) [@mgrover1](https://openradar.discourse.group/u/mgrover1)\ **Post date:** [October 18, 2023, 1:59pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/5 "2023-10-18T13:59:47Z")
@Jagdish_jena - this line is the culprit. What is the reasoning for this line? radar.sweep\_start\_ray\_index[‘data’] = np.array([0]) This will corrupt the radar object, leading to mismatched array lengths. ---
**Author:** ![mgrover1](https://yyz2.discourse-cdn.com/free1/user_avatar/openradar.discourse.group/mgrover1/32/7_2.png) [@mgrover1](https://openradar.discourse.group/u/mgrover1)\ **Post date:** [October 19, 2023, 8:22pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/6 "2023-10-19T20:22:44Z")
@Jagdish_jena - did this solve the issue? ---
**Author:** ![Jagdish\_jena](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@Jagdish\_jena](https://openradar.discourse.group/u/Jagdish_jena)\ **Post date:** [October 20, 2023, 10:37am UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/7 "2023-10-20T10:37:35Z")
Actually the file i have sent you it is working . This file was taken from thumba radar and has clutter and some time and sweep parametre is missing .so i have processed it and convert it into a nc file . That processed file is not working using that code. I am sending you a sample . please check . > **[RCTLS\_13MAY2018\_135449\_L2B\_STD (1).nc](https://drive.google.com/file/d/1aLqZ_N6NKlsfl3SaJmQap1ZXiVSSRV9b/view?usp=sharing)** > > Google Drive file. ---
**Author:** ![Jagdish\_jena](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@Jagdish\_jena](https://openradar.discourse.group/u/Jagdish_jena)\ **Post date:** [October 20, 2023, 6:32pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/8 "2023-10-20T18:32:22Z")
There is another problem i am facing i.e after processing through that code results value are coming very absurd . just check following figures 1. PHIDP (raw data ) ![PHIDP_RAW](https://global.discourse-cdn.com/free1/uploads/openradar/original/1X/4a7f62f2167d9f464d952203694e3b3662186160.jpeg) 2.calculated PHIDP ![processed PHIDP](https://global.discourse-cdn.com/free1/uploads/openradar/original/1X/218e0b4245fa4ca1cb25393bc6764cab69f7cc3d.jpeg) 3.UNFOLDED PHIDP - zero 4.KDP ![calculated KDP](https://global.discourse-cdn.com/free1/uploads/openradar/original/1X/47726a1cc4e48af831c99d17fd093a654011c58a.jpeg) i dont know what is the problem . it is the problem with data or methods . because i have tried everything pyart , wradlib, titan didn’t get any satisfied result. ---
**Author:** ![Jagdish\_jena](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@Jagdish\_jena](https://openradar.discourse.group/u/Jagdish_jena)\ **Post date:** [October 28, 2023, 4:52pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/9 "2023-10-28T16:52:44Z")
@mgrover1 have u checked above figures ? ---
**Author:** ![mgrover1](https://yyz2.discourse-cdn.com/free1/user_avatar/openradar.discourse.group/mgrover1/32/7_2.png) [@mgrover1](https://openradar.discourse.group/u/mgrover1)\ **Post date:** [October 30, 2023, 3:45pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/10 "2023-10-30T15:45:32Z")
I have not had a chance yet - plan to take a look this week. ---
**Author:** ![mgrover1](https://yyz2.discourse-cdn.com/free1/user_avatar/openradar.discourse.group/mgrover1/32/7_2.png) [@mgrover1](https://openradar.discourse.group/u/mgrover1)\ **Post date:** [November 2, 2023, 1:18pm UTC](https://openradar.discourse.group/t/error-in-phase-processing/329/11 "2023-11-02T13:18:36Z")
I suspect this is related to the data quality - I tried with multiple methods and found the same results.