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# RE: Calculation Software

• To: <seaint(--nospam--at)seaint.org>
• Subject: RE: Calculation Software
• From: "Bill Allen" <T.W.Allen(--nospam--at)cox.net>
• Date: Tue, 20 Jul 2004 12:57:39 -0700

```Regarding naming cells (or a range of cells for that matter), you can't use
names like "P1" because that will return the value of cell P1. I shouldn't
say you "can't", but you "shouldn't". Of course you "can", but you won't
like the results.

What's fun is using an array. You can do matrix functions with Excel the
same way. For example, take the four seismic coefficients derived from UBC
section 1630.2.1 and put them in cells b2, b3, b4 and b5. Just to test, put
0.1, 0.2, 0.3 and 0.4 in those cells. Now, highlight the cells and go to the
name box and type "keq" (range names are not case sensitive). Now, go to
cell b6 and drag down so that you have a total of 4 cells highlighted and
type "=keq/1.4" without the quotes. Now, before you hit "enter", hold down
the control key, hold down the shift key, stick your tongue out and THEN hit
enter. You should (if you held your tongue out right) have the ASD seismic
coefficients in cells b6 through b9.

Now, say you have a range consisting of a stiffness matrix named "k" and a
range consisting of a force matrix named "Q". To get the resulting
displacements, all you have to do is type in "=mmult(minverse(k),Q)"
(without the quotes, hold down the control key, hold down the shift key and
THEN hit enter.

Voila!

When you look at the contents of the cell, the control, shift, enter
sequence puts the {} brackets around the expression to let Excel know that
this is a matrix operation. Excel calls it arrays, if you want to look it up
in the help file.

Another thing that's nice about naming ranges (even if the range is an
individual cell) is that the work is much more transportable. If you write a
piece of work that you want to insert into another spreadsheet, I always
have problems with relative and absolute referencing because I never put the
work in the new spreadsheet in the exact same location as the original file.
Using range names fixes that. The only problem is that, eventually, names
get used up. One of the problems I have is naming the cantilever length of a
beam as "a" and then using the cross sectional area of the beam section "A".
With range names, these are the same value, so I have to change one of them.
I usually change area from "A" to "Area", but I could just as easily change
the cantilever length to "RtCant" or "LtCant" or just "Cant". I just HATE
the word "Cant", as in "Can't" :o).

To me, range naming is a HUGE tool for quality control in making sure I have
the correct expression.

T. William (Bill) Allen, S.E. (CA #2607)
ALLEN DESIGNS
Consulting Structural Engineers
http://www.AllenDesigns.com
V (949) 248-8588	 .	 F (949) 209-2509

-----Original Message-----
From: Jeremy South [mailto:jslist(--nospam--at)jenkins-engineering.com]
Sent: Tuesday, July 20, 2004 12:23 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Calculation Software

That is awesome! While I'm decent with Excel, I didn't know you could rename
the cells and use the names as reference in formulas. My boss was unaware of
it as well, and he's been doing Excel programming for years. Needless to
say, he was thrilled.

Jeremy South, EI, LSI
Tupelo, MS

----- Original Message -----
From: "Christopher Wright" <chrisw(--nospam--at)skypoint.com>
Sent: Tuesday, July 20, 2004 09:22
Subject: RE: Calculation Software

> >This gives me a cell with the
> >formula written in text form, and it is easier to write the formula using
> >names vs cell locations.
> Neat, eh?
>
> Christopher Wright P.E.    |"They couldn't hit an elephant at
> chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
> ___________________________| John Sedgwick, Spotsylvania 1864)
> http://www.skypoint.com/~chrisw
>
>
>
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