Hello to everyone...
I am trying to learn how mathcad uses arrays. I am looking at mathcad v.15's quicksheet example.
Here is an excerpt that I don't understand at all.
I am trying to create something similar myself......something simple, such as a variable with two colums and one row, but I am unable to reproduce that following the example mathcad provides. I have looked over all the help and quicksheets, but mathcad gleans over too much and doesn't come right out and specify how it is creating this kind of array --- with the braces "{a,b}" elements in the above "M" array....or matrix.
Can someone shed some light on this please? I am stuck and out of ideas on my own.
Thank you!
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Hi Werner...
Thanks for letting me know.
I was not aware it did not show in my original post.....<sigh>
Since I don't see any concievable way to 'attach' a file here......I resorted to taking a screen-shot. It seems the only way to do it ----- [?]
If I create a 1x2 matrix say: B = |a b|, you're saying that "a" and "b" are both matrices as well? And mathcad indicates that with the braces?
Only if a and b are matrices themselves. Then you would create a nested matrix and you can decide in the display options if MC should expand the nested arrays or not.
RICHARD GRAUSLYS wrote:
Bit stymied here,
just want to reach individual elements in the nested matrices...
i.e matrix is [200,200,25], and I can reach the 1x25 vector with the usual M[i,j] 2D addressing convention
Would be very simple with 3d array addressing... e.g. M[i,j,k], but Prime's convention, though clumsy, should work
the manual's suggested short cut keystroke doesn't seem to work (ie tried these: "Control" + "5"; "Control" + "shift" +"5"), Prime 3.1 ignores the typed shortcut in all the syntax permutations I've tried. Anyone find a clear example of the proper syntax?
Select the M[i,j] then index that as you would normally do.
Here's how to do it in Mathcad 15 (I haven't got Prime).
Stuart
looks like the same syntax, no joy is all typing permutations tried.
Nothing like software to make one feel stoopid.
The problem you experience in your screenshot stems from the fact, that a vector in Mathcad always has to be a column vector. With just one index you can only address single elements of a column vector!
Your k is a row vector and so you need to provide both indices to access a single element, even though the first index must always be 0.
Compare with
Regards,
Werner
RICHARD GRAUSLYS wrote:
Would be very simple with 3d array addressing... e.g. M[i,j,k], but Prime's convention, though clumsy, should work
You'll probably receive a warning from one or two of the long-standing members about mentioning Multi-Dimensional Arrays (MDAs) when I'm around - not to mention my cardiologist and my psychiatrist (for the sake of the latter's health, not mine), and the local police or special forces firearms response teams. 
I've only been requesting MDAs (and proper indexing) for about 16 years, and am now at the point where I think I might take The Voices' advice about cleaning the weapons 
.
How any modern software claiming to be "mathematical" can fail to provide proper support for MDAs is beyond my ability to comprehend - it's not like it's difficult, and there is a shed-load of libraries PTC could choose from if they didn't want to write their own.
Stuart
?
VladimirN. wrote:
Where's your shield, Stuart ?
Мой щит? Lost it on the MDA battlefield somewhere, Vladimir. It disappeared somewhere into the 4th dimension and I couldn't get it back - no index. 
(It's because I used my work account to reply to Richard, rather than my personal account)
Stuart
VladimirN. wrote:
Scottish knights must always be alert, especially during working hours.
Be Alert! We need more Lerts!
Stuart
(I'm half-Welsh (Я наполовину валлийский??), which means long-range weapons are more my style, anyway! )
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