ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Thu, 25 Mar 2021 02:03:28 +0100matrix is found singular over CC, nonsingular over CDFhttps://ask.sagemath.org/question/56365/matrix-is-found-singular-over-cc-nonsingular-over-cdf/I am trying to take the inverse of complex valued matrix where every entry is either +/-1,+/-i,or 0. The matrices are quite large and I am getting substantial rounding errors when I construct the matrix using "matrix(CDF,array)" and then take the inverse, but I still get an output.
When I construct the matrix using the same array but using "matrix(CC,array)" and then take the inverse I get this error:
ZeroDivisionError: input matrix must be nonsingular
I am confused because the array when I use "matrix(CC,array)" is exactly the same as the array when I use CDF, however "matrix(CDF,array)" is nonsingular and the function inverse works.
Why is this happening and is there another way I can avoid large rounding errors when taking the inverse?
I hope this is enough detail. I'm not really sure how to provide an example of this error occurring since the smallest example of the array I am
working with is still quite large (52x52) and I haven't been able to get this error to occur with smaller simpler arrays.
This is the encoded matrix over the Gaussian Integers - I had been using QQbar() to run it since it worked to get the inverse.
`b = [286102294921876, 178813934326175001, 69849193096160908206250, 27284841053187847167978515625, 10658141036401502788066894531250000, 179100036621093756, 111937522888183596880, 69960951805114746112500, 43725594878196716328140625, 27343048714101314544736328125, 17080310499295592308075000000000, 10675194062059745192527954101562500, 1716613769531255, 112652778625488296880, 44004991650581359960953125, 17189449863508343696746875000000, 63948846218409016728401336669921875, 895500183105468780, 559687614440917984400, 349804759025573730562500, 218627974390983581640703125, 136715243570506572723681640625, 85401552496477961540375000000000, 53375970310298725962639770507812500, 8583068847656275, 563263893127441484400, 85947249317541718483734375000000, 319744231092045083642006683349609375, 4477500915527343900, 2798438072204589922000, 1749023795127868652812500, 1093139871954917907959375000, 683212419971823692323242187500, 427007762482389807701875000000000, 266879851551493629813198852539062500, 42915344238281375, 2816319465637207422000, 1100124791264533997803125000, 429736246587708592418671875000000, 1598721155460225418210033416748046875, 22387504577636719500, 13992190361022949610000, 8745118975639343264062500, 5465699359774589539796875000, 3416062099859118461616210937500, 2135038812411949038509375000000000, 1334399257757468149065994262695312500, 35762786865235000, 13969838619232179688125, 5456968210637569433595703125, 2131628207280300557632452392578125, 1332267629550187848508377075195312500]`
The issue I'm now having is that I expected the inverse this matrix to look much different - as well as the determinant to be much larger.beanplantzThu, 25 Mar 2021 02:03:28 +0100https://ask.sagemath.org/question/56365/