Regarding Dimensions of Array

Hi ..well i am just wondering wht is the limit to Dimension of Array in Java. my ultimate goal is to handle large matrices.
Looking forward for your response..thanking u ..!!

Hmmm... that question could be interpreted in at least two ways.
1. How many dimensions can an array type have? I believe the answer is around 255.
2. How many levels of arrays can be stored in any array? This is limited only by available memory.
Remember that "multidimensional arrays" are really just arrays of arrays, and that arrays are objects. Thus, you could have an array of objects whose elements are actually arrays:
Object[] deep = new Object[10];
deep[0] = new Object[10];
((Object[]) deep[0])[0] = new Object[10];
((Object[]) ((Object[]) deep[0])[0])[0] = new Object[10];
// etc.Actually, an element of an array can be a reference to the array itself:
Object[] recursive = new Object[1];
recursive[0] = recursive;so in a sense that is a "bottomless" array!
If you're willing to code the array accesses with lots of casts, you can handle any number of dimensions, and even arrays of "ragged" dimension.

Similar Messages

Two dimension string array in teststand

Hello,
I want to pass a two dimension string array from a labWindows dll into Teststand. My labwindows dll:
#define NR_columns 12
#define NR_rows 1200
#define NR_hight 1024
int__declspec(dllexport) __stdcall sort( char pspec[NR_columns][NR_rows][NR_hight])
The call of the dll in teststand looks like the attached picture in the doc file.
and I got the error message which shows the attached second picture in the doc file
what is the problem?
regards
samuel
Attachments:
Error1.doc ‏94 KB

Hello Samuel,
I'm not experienced in LabWindows but I think the reason for this Error is the dimension of FileGlobals.loadspec in TestStand. The Error Dialog displays for this String Array [0..11][0..1200]. That's an array of 12 and 1201 elements but function is expecting 12 and 1200 elements.
I hope this helps.
Kind regards
C. Dietz
Test Engineering
digades GmbH
www.digades.com

Multi-dimensioned global arrays

I'm using a couple of global multi-dimensioned string arrays (they're used in multiple functions throughout the program) and I don't know the boundaries of either dimension until run-time.
It works fine to use the "new" on a single-dimensioned array, but I'm getting a compiler error when I try:
std::string* dta = new std::string[x][y];
Any ideas what the problem is?

It works fine to use the "new" on a single-dimensioned array, but I'm getting a compiler error when I try:
std::string* dta = new std::string[x][y];
How do I declare a 2d array in C++ using new?
http://stackoverflow.com/questions/936687/how-do-i-declare-a-2d-array-in-c-using-new
- Wayne

Regarding Dimension Table and Fact table

Hello,
I am having basic doubts regarding the star schema.
Let me explain first regarding star schema.
Fact table containes Key fiigures and Dim IDs,Ok,
These DIm ids will be connected to my dimension tables.The Dimension table contains Characterstics and these Dim ids ,Ok.
Then My basic doubt
1.How does DIm id will be linked to SID tables
2.If I have not maintained any master data or text or Heirachies then SID tables will it be generated or not?
3.If it is generated I think there is use of This SID now..as we have not maintained Master data.
4.I am haing 18 characterstic which are no way related to each other in that scnerio how does Dimensions have to identified.?or we need to inclued whole chracterstics in one dimensions or we need to create seprate dimesnions for each of them..?(max is 13 dimensions)
5.If Dimension table contains dim ids and characterstics then where does the values for characterstics will be stored...?
( for ex..sales rep is characterstics for this we will be giving values some names where does these values will be stored..)

hi Vasu,
e.g we have infocube with
- dimension 'location' -> characteristic 'sales rep', 'country'
- dimension 'partner'.
fact table
dim-id('sales person') dim-id('partner') revenue
1001                   9001              500
1002                   9002              300
1003                   9004              200
dimenstion table 'location'
dim-id sid-id(sales rep) sid-id(country)
1001    3001              5001
1002    3004              5004
1003    3005              5001
'sales rep' sid table
sid   sales rep
3001 abc
3004 pqr
3005 xyz
'country' sid table
5001      country1
5004      country2
so from the link dim-id and sid, we get
"sales rep report"
sales-rep   revenue
abc        500
pqr        300
xyz        200
"country report"
country    revenue
country1   700
country2   300
hope it's clear.

Regarding Dimensions

Hi Experts,
Please tell me how to decide which charecteristic has to be inserted in which dimension.. Is there any criteria for that?
Immediate replies will help me a lot...
Advance Thanks & regards,
Chintu

First finalize the star schema model identifying fact table and its key figures (Ex: Revenue, Quantities etc) then decide the dimensions based on which the data is going to be sliced and diced (Dimension Ex: Customer, Product, Employee, Time etc). Then find out what are the various dimensional characteristics available in the source system. Based on that information now you may have to choose what are the various attributes you would like to keep inside the infocube for these dimensional characteristics and which are the attributes you would like to keep outside the cube as master data attributes of the characteristics in the dimensions. For example Material number, plant and store location can be inside the cube as characteristics and product hierarchy, text and other material related attributes can be outside the cube as master data attributes. Note use of master data attributes facilitates data loads and very dynamic as it can be resused with various cubes but it can slow down queries as it increases more table joins to read during query execution.
So as a developer you will have to choose the data model based on the user requirements, volume of data and number of dimension characteristics and their attributes and decide on where to keep what attributes either inside the cube or outside the cube.
Hope this helps please assign points if it does.
Thanks
A Ramasubbban

Dimension an array with BigInteger?

Hi,
I'm wondering if it is possible to dimension an HUGE array with BigInteger..
my idea is if it is possible to the equivalent of e.g.
boolean b[] = new boolean[new BigInteger("12345678987654322346567")];Thanks!

No. The number in [] must be of type int (or promoted to int):
See: http://java.sun.com/docs/books/jls/second_edition/html/expressions.doc.html#46168
"The type of each dimension expression within a DimExpr must be an integral type, or a compile-time error occurs. Each expression undergoes unary numeric promotion (�5.6.1). The promoted type must be int, or a compile-time error occurs; this means, specifically, that the type of a dimension expression must not be long."

Regarding dimension creation

Hi,
When I am creating a dimension it gives the default attributes like
ID-- surrogate Identifier
Name-- Business Identifier
Description Business Identifier
I have to create a dimension.
My dimension does not have these attributes.(ID,Name,Description).
Do I need to take all three default attributes or can I delete it.
I have to create 2 levels.
Is it necessary to take surrogate,Business Identifiers for each level.
Is it compulsary to add Surrogate Identifier for each level.
How can we decide the surrogate, Business Identifiers.
My dimension has 3 columns as a Primaykey.
It is urgent.
Please give me the suggestions.
Thanks,
Venkat

Hi Venkat
You do not need to define surrogate attributes. The slowly changing support in OWB needs surrogates, BUT you can model dimensions specifying just the business attributes (the level identifying attributes) and load the dimension table using a table operator in a map. Now I might be mixed up with all of my OWB versions but the wizard should allow you to delete/rename these attributes.
Cheers
David

Regarding passing table array to sap scripts - urgent

Hi Experts,
I am calling an SAP Script form from a custom program. The code snippet is as follows:
MOVE : 'ZFRM_EX_COM_INV' TO w_form.
PERFORM open_form USING w_form.
PERFORM write_form USING 'MAIN'     'HEADER'.
PERFORM write_form USING 'MAIN'     'LINE_ITEM'.
LOOP AT it_cond INTO wa_cond.
<b>PERFORM write_form USING 'TOTAL' 'TOTAL_COND'.</b>
               <i> " TOTAL is the page window and TOTAL_COND is the element.</i>
ENDLOOP.
PERFORM close_form.
*&      Form write_form
      text
     -->VAR1       text
FORM write_form USING var1 var2.
IF var2 IS INITIAL.
    CALL FUNCTION 'WRITE_FORM'
      EXPORTING
        window                   = var1
      EXCEPTIONS
        element                  = 1
        function                 = 2
        type                     = 3
        unopened                 = 4
        unstarted                = 5
        window                   = 6
        bad_pageformat_for_print = 7
        OTHERS                   = 8.
ELSE.
    CALL FUNCTION 'WRITE_FORM'
      EXPORTING
        element                  = var2
        window                   = var1
      EXCEPTIONS
        element                  = 1
        function                 = 2
        type                     = 3
        unopened                 = 4
        unstarted                = 5
        window                   = 6
        bad_pageformat_for_print = 7
        OTHERS                   = 8.
ENDIF.
ENDFORM.                               " WRITE_FORM
In the text that is in bold in teh code snippet, I am tring to pass the values one-by-one and print in the output.
But only the last line item from that table is begining printed. The other lines are overwritten by the last line.
How should I display all the lines in the internal table it_cond.
Please help me...
regards,
arul jothi a.

U are using a variable window to print the 'total_cond' text element..
so whenever u call the write form   for a variable window .. it will get over written by the current contents.. I t wont append the contents to the form...
Instead u use this text element in the MAIN window then onli u will get all the data..
i hope this is the problem..
reward if it helps u...
sai ramesh

Smart View message regarding "dimension meber..found in comment region"

I created a report through Hyperion Smart View and it works well. However, I got a several messages like "Dimension member ...found in comment region at grid row 160 column 6 is being deleted" for entitiy members. The report will be refreshed but those entity members in messages will show blank. Can anyone help? Thanks.

this usually means there's a member incorrectly typed in one of the columns of that row, and smartview gets confused, thinking that row is for comments, and that the referenced column (6) therefore shouldn't be a member
Jon Keskitalo

Reading in a multi dimension binary array

Greetings,
I am attempting to read in a binary file which contains data in a 1440x320x7x2 array. The method I am currently attempting to use is DataInputStream. But, it seems this method can only return a single dimensional array. Any tips?
TIA

It depends how it was written. If it was written by calling writeObject() on the whole 4D array, then calling readObject() will give you that whole array back.
If it was written by writing out individual elements with writeData, then you'll have to use readData and build up the array piecemeal.
If it was something inbetween, like calling writObject 1440 times on the 3D arrays, then you'll have to do the inverse of that.
See the pattern?

Auto-indexing is slow for arrays with 1 dimensions

Hi,
I was looking at the performance of operations on all individual elements in 3D arrays, especially the difference between auto-indexing (left image) and manual-indexing (right image, calling "Index array" and "Replace array subset" in the innermost loop). I'm a bit puzzled by the results and post it here for discussion and hopefully somebody's benefit in the future.
Left: auto-indexing; right: manual-indexing
In the tests I added a different random number to all individual elements in a 3D array. I found that auto-indexing is 1.2 to 1.5 times slower than manual-indexing. I also found that the performance of auto-indexing is much more dependent on the size the dimensions: an array with 1000x200x40 elements is 20% slower than an array with 1000x40x200 elements. For manual-indexing there is hardly any difference. The detailed results can be found at the end of this post.
I was under the impression that auto-indexing was the preferred method for this kind of operation: it achieves exactly the same result and it is much clearer in the block diagram. I also expected that auto-indexing would have been optimized in LabView, but the the tests show this is clearly not the case.
What is auto-indexing doing?
With two tests I looked at how auto-index works.
First, I looked if auto-indexing reorganizes the data in an inefficient way. To do this I made a method "fake-auto-indexing" which calls "Array subset" and "Reshape array" (or "Index array" for a 1D-array) when it enters _every_ loop and calls "Replace array subset" when exiting _every_ loop (as opposed to manual-indexing, where I do this only in the inner loop). I replicated this in a test (calling it fake-auto-indexing) and found that the performance is very similar to auto-indexing, especially looking at the trend for the different array lengths.
Fake-auto-indexing
Second, I looked if Locality of reference (how the 3D array is stored in memory and how efficiently you can iterate over that) may be an issue. Auto-indexing loops over pages-rows-columns (i.e. pages in the outer for-loop, rows in the middle for-loop, columns in the inner for-loop). This can't be changed for auto-indexing, but I did change it for manual and fake-indexing. The performance of manual-indexing is now similar to auto-indexing, except for two cases that I can't explain. Fake-auto-indexing performs way worse in all cases.
It seems that the performance problem with auto-indexing is due to inefficient data organization.
Other tests
I did the same tests for 1D and 2D arrays. For 1D arrays the three methods perform identical. For 2D arrays auto-indexing is 15% slower than manual-indexing, while fake-auto-indexing is 8% slower than manual-indexing. I find it interesting that auto-indexing is the slowest of the three methods.
Finally, I tested the performance of operating on entire columns (instead of every single element) of a 3D array. In all cases it is a lot faster than iterating over individual elements. Auto-indexing is more than 1.8 to 3.4 times slower than manual-indexing, while fake-auto-indexing is about 1.5 to 2.7 times slower. Because of the number of iterations that has to be done, the effect of the size of the column is important: an array with 1000x200x40 elements is in all cases much slower than an array with 1000x40x200 elements.
Discussion & conclusions
In all the cases I tested, auto-indexing is significantly slower than manual-indexing. Because auto-indexing is the standard way of indexing arrays in LabView I expected the method to be highly optimized. Judging by the tests I did, that is not the case. I find this puzzling.
Does anybody know any best practices when it comes to working with >1D arrays? It seems there is a lack of documentation about the performance, surprising given the significant differences I found.
It is of course possible that I made mistakes. I tried to keep the code as straightforward as possible to minimize that risk. Still, I hope somebody can double-check the work I did.
Results
I ran the tests on a computer with a i5-4570 @ 3.20 GHz processor (4 cores, but only 1 is used), 8 GB RAM running Windows 7 64-bit and LabView 2013 32-bit. The tests were averaged 10 times. The results are in milliseconds.
3D-arrays, iterate pages-rows-columns
pages x rows x cols : auto    manual fake
   40 x 200 x 1000 : 268.9   202.0   268.8
   40 x 1000 x 200 : 276.9   204.1   263.8
200 x   40 x 1000 : 264.6   202.8   260.6
200 x 1000 x   40 : 306.9   205.0   300.0
1000 x   40 x 200 : 253.7   203.1   259.3
1000 x 200 x   40 : 307.2   206.2   288.5
100 x 100 x 100 : 36.2    25.7    33.9
3D-arrays, iterate columns-rows-pages
pages x rows x cols : manual fake
   40 x 200 x 1000 : 277.6   457
   40 x 1000 x 200 : 291.6   461.5
200 x   40 x 1000 : 277.4   431.9
200 x 1000 x   40 : 452.5   572.1
1000 x   40 x 200 : 298.1   460.4
1000 x 200 x   40 : 460.5   583.8
100 x 100 x 100 : 31.7    51.9
2D-arrays, iterate rows-columns
rows x cols : auto     manual   fake
200 x 20000 : 123.5    106.1    113.2
20000 x   200 : 119.5    106.1    115.0
10000 x 10000 : 3080.25 2659.65 2835.1
1D-arrays, iterate over columns
cols   : auto manual fake
500000 : 11.5 11.8    11.6
3D-arrays, iterate pages-rows, operate on columns
pages x rows x cols : auto    manual fake
   40 x 200 x 1000 : 83.9   23.3     62.9
   40 x 1000 x 200 : 89.6   31.9     69.0
200 x   40 x 1000 : 74.3   27.6     62.2
200 x 1000 x   40 : 135.6   76.2    107.1
1000 x   40 x 200 : 75.3   31.2     68.6
1000 x 200 x   40 : 133.6   71.7    108.7
100 x 100 x 100 : 13.0    5.4      9.9
VI's
I attached the VI's I used for testing. "ND_add_random_number.vi" (where N is 1, 2 or 3) is where all the action happens, taking a selector with a method and an array with the N dimensions as input. It returns the result and time in milliseconds. Using "ND_add_random_number_automated_test.vi" I run this for a few different situations (auto/manual/fake-indexing, interchanging the dimensions). The VI's starting with "3D_locality_" are used for the locality tests. The VI's starting with "3D_norows_" are used for the iterations over pages and columns only.
Attachments:
3D_arrays_2.zip ‏222 KB

Robert,
the copy-thing is not specific for auto-indexing. It is common for all tunnels. A tunnel is first of all a unique data space.
This sounds hard, but there is an optimization in the compiler trying to reduce the number of copies the VI will create. This optimization is called "in-placeness".
The in-placeness algorithm checks, if the wire passing data to the is connected to anything else ("branch"). If there is no other connection then the tunnel, chance is high that the tunnel won't create an additional copy.
Speaking of loops, tunnels always copies. The in-placeness algorithm cannot opt that out.
You can do a small test to elaborate on this: Simply wire "0" (or anything less than the array sizy of the input array) to the 'N' terminal.......
Norbert
PS: Auto-indexing is perfect for a "by element" operation of analysis without modification of the element in the array. If you want to modify values, use shift registers and Replace Array Subset.
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

HELP: Run-time array dimension in LabVIEW formula node

I need to dimension an array at run time within a formula node as follows:
int32 i,N;
N = sizeOfDim(inputArray,0);
float64 outputArray[N];
for (i = 0; i outputArray[i] = myfunction(inputArray[i]);
However, LabVIEW complains "Formula Node: index list expected". On the
other hand, if I say
float64 outputArray[1000];
LabVIEW is perfectly happy. But that's not what I need to do! Is there
an alternative
way of accomplishing my goal?
BTW, I've tried calculating N outside the formula node and then
presenting it as
an input with the same results. I've got a bad feeling that run time
array dimensioning
just isn't allowed.
TIA,
Hugh

Can't you just use the Initialize Array function outside the formula node and pass that instead?

Maximum number of dimensions for an array

What is the maximum number of dimensions an array can accept:
a. 266
b. 255
c. 256
d. 250
which option is correct and why?

sabre150 wrote:
I don't know and I most definitely don't care since anything more than 2 is, in my opinion, just silly.It's also quite untractable from a memory standpoint. Say you have an 10 by 10 by 10 array. That's 10^3 elements. Now say you have 250 dimensions, that's 10^250 elements which is a huge number in the order of the number of atoms in the universe or so.
Say you instead have just 1 element in each dimension. Then you got a total of 1^250 elements, which is 1 element. That's okay but you don't need the array because 1 element is a variable. This means an array has at least 2 elements in each dimension. That's 2^250 elements which is like 10^75 which is also a huge number. You wouldn't get that kind of memory even if you added up all computers that ever existed.
So array dimensions in the order of 250 aren't just silly, there isn't enougth memory for them.

Can I write a subVI that accepts a generic-dimension array?

I'd like to write a subVI with an input that is an array. The thing is, sometimes the array will be 1D, sometimes 2D, sometimes more.
If I try to pass an array reference, the reference "knows" what dimension the array is.
If I pass the array directly then I'm hardwired to accept whatever kind of array I put in my subVI as the input.
Is there a way to pass an array reference that is NOT specifically dimensioned?
A related question: Is there a way to get the array's dimension from a property node? As far as I can tell the only way is the get the value property and then use Array Size. It seems like the array's dimension should be a property.

Hello again Bmarsh
> I'd like to write a subVI with an input that is an array. The thing
> is, sometimes the array will be 1D, sometimes 2D, sometimes more.
>
> If I try to pass an array reference, the reference "knows" what
> dimension the array is.
>
> If I pass the array directly then I'm hardwired to accept whatever
> kind of array I put in my subVI as the input.
>
> Is there a way to pass an array reference that is NOT specifically
> dimensioned?
When you create the array control refnum on the subVI, make sure it is not
strictly typed to an actual array. Create it from the palette (Control
Refnum)
and select Array class or otherwise unselect "Include Data Type" in the
right-click menu of the control refnum. Then the reference is generic to an
N dimensi
onal array.
>
> A related question: Is there a way to get the array's dimension from a
> property node? As far as I can tell the only way is the get the value
> property and then use Array Size. It seems like the array's dimension
> should be a property.
You can have it indirectly reading the "Index Values" property, which is an
array of indices (one per dimension) of the element displayed in the
top-left corner of the array indicator. the length of this 1D array is the
number of dimension of the referenced array.
Jean-Pierre Drolet
LabVIEW, C'est LabVIEW

How to clear an array?

I want to clear an one dimension and also 2-dimension numeric arrays. Is there a single command that does it?
Thanks
Rafi

HI,
Here is an example of using the ArrayDimensions
Locals.arrOneDim.Type.ArrayDimensions.SetBoundsByStrings("[0]","[0]" )Locals.arrTwoDim.Type.ArrayDimensions.SetBoundsByStrings("[0][0]","[0][0]" )
There is a SetBounds which you can use a long array so its of the format
Locals.arrTwoDim.Type.ArrayDimensions.SetBounds({0,0},{0,0})
Regards
Ray Farmer
Message Edited by Ray Farmer on 11-11-2008 09:55 PM
Regards
Ray Farmer

Regarding Dimensions of Array

Similar Messages

Maybe you are looking for