{"id":281823,"date":"2023-05-01T19:57:03","date_gmt":"2023-05-01T19:57:03","guid":{"rendered":"\/forum\/forums\/topic\/issues-with-array-splicing-and-power-calculation-in-mode\/"},"modified":"2023-05-01T20:07:48","modified_gmt":"2023-05-01T20:07:48","slug":"issues-with-array-splicing-and-power-calculation-in-mode","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/issues-with-array-splicing-and-power-calculation-in-mode\/","title":{"rendered":"issues with array splicing and power calculation in MODE"},"content":{"rendered":"

I have calculated the poynting vector for my simulation and stored its magnitude in an array called S.<\/p>\n

S has dimensions (2081,361) and my simulation domain extends from -26um to 26um in the horizontal and 5um to -4um in the vertical. <\/p>\n

I use the following script to get the normalized power in the region bounded from 5um to 0um and -26 to 26um:<\/p>\n

x1=26e06;<\/p>\n

x2=-26e-06;<\/p>\n

z1=5e-6;<\/p>\n

z2=0e-6;<\/p>\n

selectmode(1);<\/p>\n

setanalysis(“integration shape”,”rectangular”);<\/p>\n

setanalysis(“z1”,z1);setanalysis(“z2”,z2);<\/p>\n

setanalysis(“x1”,x1);setanalysis(“x2”,x2);<\/p>\n

area=getanalysis(“fraction integrated”);<\/p>\n

?area;<\/p>\n

BUT, if I were to splice the array ‘S’ as x = S(:,1:201) where 1 is the row index corresponding to 5um and 201 is the index corresponding 0um in my simulation domain and then I perform a sum(x)\/sum(S) I get an incorrect answer to what is given in the script above.<\/p>\n

However if I splice the array ‘S’ as x = S(:,161:361) and then take the sum(x)\/sum(S), I get the correct value given by the script above. I do not understand why this gives the correct result because this captures the array values which are beneath the region I specified in the script, why in a manual calculation using array splicing I need to specify indices which do not belong to the region 5um to 0um vertical, but instead specify 0 to -4um vertical. A pic of S is shown below.<\/p>\n

 <\/p>\n

\"\"<\/a><\/p>\n

Also, if I use GUI power integration, it gives correct answer as script:<\/p>\n

\"\"<\/p>\n

what am I not understanding about splicing in lumerical, or what am I not understanding about the built in ‘fraction integrated’ function? <\/p>\n

Thanks<\/p>\n","protected":false},"template":"","class_list":["post-281823","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t