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+--- Thread: Not returning correct Matrix Calculation (/thread-16823.html)
Not returning correct Matrix Calculation - Amer7 - 04-27-2021 06:47 PM
My calculator is not giving me the correct matrix calculation.
Code:
2568.0000 -2568.00 1 0
2568.0000 2568.00000 0 1
3852.1284 -2568.00 1 0
2568.0000 3852.12840 0 1
3536.9834 -3411.36 1 0
3411.3569 3536.98344 0 1
That is Matrix A
Matrix O
-4851346.102
-6513502.217
-4850456.274
-6513809.817
-4850472.619
-6513149.860
TRN(A)*A should be
58770372.8276 0.0000 9957.1118 8547.3569
0.0000 58770372.8276 -8547.3569 9957.1118
9957.1118 -8547.3569 3.0000 0.0000
8547.3569 9957.1118 0.0000 3.0000
Inverse(TRN(A)*A) should be
7.29974E-07 -1.81352E-22 -0.002422813 -0.002079784
-2.53893E-21 7.29974E-07 0.002079784 -0.002422813
-0.002422813 0.002079784 14.30029098 0
-0.002079784 -0.002422813 -4.54077E-14 14.30029098
But I get different numbers than in Excel, im using Shift + devide key to inverse. Can someone explain, and later in my calculation i get wrong answer because of Inverse mistake.
TRN(A)*O should be
-1.03972E+11
-23394687040
-1.46E+07
-1.95E+07
- I get this OK, But my issue is here
M=( Inverse((TRN(A)*A) * (TRN(A)*O)
-0.6929740
0.2395352
4853740.802
6514666.637
But I get:
0.6929740
-0.2395352
-4853740.802
-6514666.637
Can someone explain why this is happening? - Im not writing a program im manually doing the calculation on Home screen.
And later
A*M+O should be
0.017
-0.011
-0.023
-0.017
0.006
0.027
but I get
0.03314
-0.01158
etc. - WRONG
I have tried to multiply the M matrix with (-1) but again calculation of O seems wrong.What is the best command for finding Inverse matrix ? same happens when i use inv(Matrix that i want to invert)
[attachment=9421]
RE: Not returning correct Matrix Calculation - Albert Chan - 04-27-2021 08:09 PM
Hi, Amer7
Tried this in Numpy, Excel numbers were wrong.
>>> from numpy import *
>>> A = array([
... [2568.0000, -2568.00 , 1, 0],
... [2568.0000, 2568.00000, 0, 1],
... [3852.1284, -2568.00 , 1, 0],
... [2568.0000, 3852.12840, 0, 1],
... [3536.9834, -3411.36 , 1, 0],
... [3411.3569, 3536.98344, 0, 1]])
>>> B = dot(transpose(A), A)
Code:
>>> print B
[[ 5.87703727e+07 -1.08281943e+01 9.95711180e+03 8.54735690e+03]
[ -1.08281943e+01 5.87703941e+07 -8.54736000e+03 9.95711184e+03]
[ 9.95711180e+03 -8.54736000e+03 3.00000000e+00 0.00000000e+00]
[ 8.54735690e+03 9.95711184e+03 0.00000000e+00 3.00000000e+00]]
>>> print linalg.inv(B)
[[ 7.29974488e-07 3.48034952e-13 -2.42281154e-03 -2.07978531e-03]
[ 3.48034952e-13 7.29972621e-07 2.07977844e-03 -2.42280733e-03]
[ -2.42281154e-03 2.07977844e-03 1.43002735e+01 1.61304069e-05]
[ -2.07978531e-03 -2.42280733e-03 1.61304069e-05 1.43002770e+01]]RE: Not returning correct Matrix Calculation - Amer7 - 04-27-2021 08:20 PM
Thank you Albert for numerous replies, I get the same numbers as you on my calculator. I guess something is wrong in Excel ( all formulas seemed ok). - I really doubt these are calculations from the teacher. The excel all matches up, with control calculations. Even my friends that use TI get the same numbers
RE: Not returning correct Matrix Calculation - Albert Chan - 04-27-2021 10:56 PM
(04-27-2021 08:20 PM)Amer7 Wrote: I guess something is wrong in Excel ( all formulas seemed ok).
It is possible the problem is not Excel.
From your attached screenshot, there were a picture suggesting A51 = A62, A61 = -A52.
Your provided A (row 5 and row 6) does not match this symmetrical pattern.
Not terribly off, but enough to mess up the numbers.
RE: Not returning correct Matrix Calculation - Amer7 - 04-28-2021 05:25 AM
(04-27-2021 10:56 PM)Albert Chan Wrote:(04-27-2021 08:20 PM)Amer7 Wrote: I guess something is wrong in Excel ( all formulas seemed ok).
It is possible the problem is not Excel.
From your attached screenshot, there were a picture suggesting A51 = A62, A61 = -A52.
Your provided A (row 5 and row 6) does not match this symmetrical pattern.
Not terribly off, but enough to mess up the numbers.
I have found the Issue, Im not sure why this happens. When number in column F have in front of them - ( minus, aka they are negative) Inverse matrix is not going to be the same as in Excel.
So when I input O matrix as all positive numbers I get inverse matrix correct.
And in last matrix calculation ( excel uses formula example (trn(A)*N) + O and when I adjust this to (trn(A)*N) - O I get everything correct.
I'm not sure why this difference is happening between calculator and Excel.
-Downloaded a virtual TI Nspire to check, they also get the same Matrix as we on our HP Prime.
-So its something querk of Excel.