Difference in output of t96 and t01 model between IDL and Python geopacks!

[qudsiramiz]

Hello,
I am testing and comparing the outputs of this geopack for two different models with those of IDL and I am getting very different results.

I have attached the figures which I plotted for this purpose. For each panel in the figure I have plotted the difference between the output from IDL and Python (b_out_idl - b_out_py). Difference from T96 are plotted in the first row whereas the difference between T01 model are plotted in the second row. The value of x_gsm is at the top left position whereas the value of DST used for the code is at top right

For both T96 and T01 model far from the earth, into the tail, the difference between two outputs is minimal, almost always less than 2nT, and thus can be ignored in most cases (Figure 1, for x_gsm = 9.98 R_E).

However, there seem to be significant difference in output when we move close to the Earth or when we are on the dayside. Though the difference is smaller for T01 outputs compared to those of T96, they are still significant, specially far from the Earth on the dayside (Figure 2).

I wonder if anyone else have had similar issues.

The parameters I used for the codes are as follows:

time = 2015-01-01 00:00:00 GMT
par = [5, 0, 1, 1, 0, 0, 0, 0, 0, 0]
x_gsm = np.linspace(-15.1, 15, 61)
y_gsm = np.linspace(-15.1, 15, 61)
z_gsm = np.linspace(-15.1, 15, 61)

I can provide the full python and IDL codes if that will help with the reproduction of these differences.

Figure 1

Figure 2

Figure 3

[tsssss]

Hello, It'll be helpful if you could attach the IDL and Python codes. Also, just want to check if you can replicate the examples in https://github.com/tsssss/geopack/blob/master/README.md. Thanks, Sheng

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On Mon, 18 Oct 2021 at 14:35, Ramiz Qudsi ***@***.***> wrote: Hello, I am testing and comparing the outputs of this geopack for two different models with those of IDL and I am getting very different results. I have attached the figures which I plotted for this purpose. For each panel in the figure I have plotted the difference between the output from IDL and Python (b_out_idl - b_out_py). Difference from T96 are plotted in the first row whereas the difference between T01 model are plotted in the second row. The value of x_gsm is at the top left position whereas the value of DST used for the code is at top right For both T96 and T01 model far from the earth, into the tail, the difference between two outputs is minimal, almost always less than 2nT, and thus can be ignored in most cases (Figure 1, for x_gsm = 9.98 R_E). However, there seem to be significant difference in output when we move close to the Earth or when we are on the dayside. Though the difference is smaller for T01 outputs compared to those of T96, they are still significant, specially far from the Earth on the dayside (Figure 2). I wonder if anyone else have had similar issues. The parameters I used for the codes are as follows: time = 2015-01-01 00:00:00 GMT par = [5, 0, 1, 1, 0, 0, 0, 0, 0, 0] x_gsm = np.linspace(-15.1, 15, 61) y_gsm = np.linspace(-15.1, 15, 61) z_gsm = np.linspace(-15.1, 15, 61) I can provide the full python and IDL codes if that will help with the reproduction of these differences. *Figure 1* [image: Figure_3] <https://user-images.githubusercontent.com/25327981/137784185-4058c4c8-93fc-42ee-8520-dc452245a665.PNG> *Figure 2* [image: Figure_2] <https://user-images.githubusercontent.com/25327981/137787058-989c43f6-9cc4-4dd5-95bc-bcf39a657d75.PNG> *Figure 3* [image: Figure_1] <https://user-images.githubusercontent.com/25327981/137784239-fb801129-daa7-41a8-a991-f3a2824a95c6.PNG> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#9>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADBMLBWEE4HDX5AVDBKBVELUHRSIDANCNFSM5GHJU4CQ> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[qudsiramiz]

Hey Sheng,
Yes I was able to reproduce the example which are in Readme file. They are exactly same.

I have uploaded the codes in my repository and have linked them here:

idl_code
python_code
idl_data_edit
plotting_code

I have tried to make the code consistent so that you can run them on your system with minimal edits. Also, please note that the codes are listed in the order they are run!

[tsssss]

Hello, The T96 coef was recently updated but I haven't uploaded the change to pip. This may explain the T96 difference. Have you tried the latest codes at https://github.com/tsssss/geopack/tree/master/geopack? Below are my tests at 2 selected points (using the updated T96 coef). I think the values from Python are in general agreement with those from IDL. I noticed your par is different in Python [5,-100,1,1,...] from IDL [5,0,1,1,...] Maybe this is why the T01 results are so different? As shown below for my test Point #2, the T01 difference between Python and IDL is <1 nT. But it reads <-20 nT in Figure 2 bx-t01. Let me know if this helps. Thanks, Sheng Point #1. for point in your IDL code at Line 5

>> import geopack.geopack as gp

Load IGRF coefficients ...

>> import datetime >> from dateutil import parser >> t1 = datetime.datetime(2015,1,1,0,0,0) >> t0 = datetime.datetime(1970,1,1) >> ut = (t1-t0).total_seconds() >> ps = gp.recalc(ut) >> xgsm,ygsm,zgsm = [0.95,0.5,5] >> par = [5,0,1,1,0,0,0,0,0,0] >> bx_t96,by_t96,bz_t96 = gp.t96.t96(par, ps, xgsm,ygsm,zgsm) >> bx_t96,by_t96,bz_t96

(16.664905592587036, 0.5368630998346164, -7.766438571515584)

>> bx_t01,by_t01,bz_t01 = gp.t01.t01(par, ps, xgsm,ygsm,zgsm) >> bx_t01,by_t01,bz_t01

(11.747186665975818, 0.9160073121038579, 7.7570418087141615)

>> bx_igrf,by_igrf,bz_igrf = gp.igrf_gsm(xgsm,ygsm,zgsm) >> bx_igrf,by_igrf,bz_igrf

(-198.86095806029613, -58.91994471219549, -329.89745764187376) IDL> *print*, [bx_t96, by_t96, bz_t96] 16.665817 0.53700743 -7.7665478 IDL> *print*, bx_t01, by_t01, bz_t01 11.944837 0.77270680 7.3268356 IDL> *print*, bx_igrf, by_igrf, bz_igrf -198.85908 -58.922195 -329.91322 Point #2, for a point in Figure 2

>> xgsm,ygsm,zgsm = [-10,0,0] >> bx_igrf,by_igrf,bz_igrf = gp.igrf_gsm(xgsm,ygsm,zgsm) >> bx_igrf,by_igrf,bz_igrf

(24.538720457834742, -0.3195681706868667, 26.965386128130422)

>> bx_t01,by_t01,bz_t01 = gp.t01.t01(par, ps, xgsm,ygsm,zgsm) >> bx_t01,by_t01,bz_t01

(37.939421306182794, 0.19814634751828214, -13.693608165120146)

>> bx_t96,by_t96,bz_t96 = gp.t96.t96(par, ps, xgsm,ygsm,zgsm) >> bx_t96,by_t96,bz_t96

(35.226061425661655, 0.24487109090381676, -15.711727726040502) IDL> *print*, [bx_t96, by_t96, bz_t96] 35.195693 0.24487109 -15.529020 IDL> *print*, bx_t01, by_t01, bz_t01 38.210491 0.18678968 -13.792622 IDL> *print*, bx_igrf, by_igrf, bz_igrf 24.537546 -0.31953970 26.966250

…

On Mon, 18 Oct 2021 at 14:58, Ramiz Qudsi ***@***.***> wrote: Hey Sheng, Yes I was able to reproduce the example which are in Readme file. They are exactly same. I have uploaded the codes in my repository and have linked them here: idl_code <https://github.com/qudsiramiz/rcn/blob/main/codes/idl_code_gh.pro> python_code <https://github.com/qudsiramiz/rcn/blob/main/codes/python_code_gh.py> idl_data_edit <https://github.com/qudsiramiz/rcn/blob/main/codes/write_edited_file.py> plotting_code <https://github.com/qudsiramiz/rcn/blob/main/codes/idl_ipy_comparison.py> I have tried to make the code consistent so that you can run them on your system with minimal edits. Also, please note that the codes are listed in the order they are run! — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#9 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADBMLBQ6ALOL4PT6L3DIRBTUHR37TANCNFSM5GHJU4CQ> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[qudsiramiz]

Hey Sheng,
Sorry for the delay in response. But yes it worked after I updated it with the latest version which is here on GitHub. Thank you so much for your help in debugging this!