Gauss elimination / linear algebra. Please help.
 

Hey guys and girls, I'm new to the forum and hoping you can help.

I have a set of 6x6 "matrices" in excel that expand out to give 6
equations each with six unknowns (it is a formula for a composite
lamina that has the 6 known moments and forces in a column on the left
hand side equal to a known 6x6 matrix multiplied by the column of six
unknown strains..hence why each equation gets 6 unknowns). There are no
non-linearites or any other complexities - just the unknowns. It could
be solved linearly or if there is some way of calculating the inverse
of my 6x6 matrix then that would work too.

This would be an easy solution in a program such as MatLab or Mathcad
but i'm completely stuck in excel. Is there some fuction that will let
me solve this... I'm thinking a gauss elimination or something similar
to 2x2 simultanious equations but for 6!

thanks a lot!
Neil


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Gauss elimination / linear algebra. Please help.
 

might "solver" work by specifying the forces that i know and having it
change the 6 unknown strains until the answers match? thanks again!
Neil


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Gauss elimination / linear algebra. Please help.
 

Google: Groups|Advanced Group Search
Subject: linear equations
Author:Alan Beban
Group:microsoft.public.excel.worksheet.functions

Alan Beban

n1ftyneil wrote:
Hey guys and girls, I'm new to the forum and hoping you can help.

I have a set of 6x6 "matrices" in excel that expand out to give 6
equations each with six unknowns (it is a formula for a composite
lamina that has the 6 known moments and forces in a column on the left
hand side equal to a known 6x6 matrix multiplied by the column of six
unknown strains..hence why each equation gets 6 unknowns). There are no
non-linearites or any other complexities - just the unknowns. It could
be solved linearly or if there is some way of calculating the inverse
of my 6x6 matrix then that would work too.

This would be an easy solution in a program such as MatLab or Mathcad
but i'm completely stuck in excel. Is there some fuction that will let
me solve this... I'm thinking a gauss elimination or something similar
to 2x2 simultanious equations but for 6!

thanks a lot!
Neil

Gauss elimination / linear algebra. Please help.
 

Excel offers several built in matrix functions, including MINVERSE().
It seems they're pretty well documented in the built-in Excel help.


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MrShorty
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Gauss elimination / linear algebra. Please help.
 

The solution below is to solve 6x6 matrices. Put your equations in cells d17
to f23, the results of the equations in cells h17 to h23. Enter the formula
in j17 and select the cells to j23. Once the cells are selected do
"control+shift+enter" the results will appear in cells j17 to j23. Of course
any ajacent cells can be used.


=MMULT(MINVERSE(D17:F23),(H17:H23))

See also
"www.dslimited.biz/excel_tutorials/simultaneouslinearequations.html"


"n1ftyneil" wrote:


Hey guys and girls, I'm new to the forum and hoping you can help.

I have a set of 6x6 "matrices" in excel that expand out to give 6
equations each with six unknowns (it is a formula for a composite
lamina that has the 6 known moments and forces in a column on the left
hand side equal to a known 6x6 matrix multiplied by the column of six
unknown strains..hence why each equation gets 6 unknowns). There are no
non-linearites or any other complexities - just the unknowns. It could
be solved linearly or if there is some way of calculating the inverse
of my 6x6 matrix then that would work too.

This would be an easy solution in a program such as MatLab or Mathcad
but i'm completely stuck in excel. Is there some fuction that will let
me solve this... I'm thinking a gauss elimination or something similar
to 2x2 simultanious equations but for 6!

thanks a lot!
Neil


--
n1ftyneil
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