SQL Server 2008, numeric library, c++, LAPACK, memory question
I am trying to send a table of numbers in SQL Server 2008
like:
1att 2att 3att 4att 5att 6att 7att ... attn
--------------------------------------------
565 526 472 527 483 529 476 470 502
497 491 483 488 488 483 496 515 491
467 516 480 477 494 497 478 519 471
488 466 547 498 477 466 475 480 516
543 491 449 485 495 468 452 479 516
473 475 431 474 460 342 471 386 549
489 477 462 428 489 491 481 483 475
485 474 472 452 525 508 459 561 529
473 457 476 498 485 465 540 475 525
455 477 415 434 475 499 476 482 551
463 476 476 471 488 526 394 439 475
479 473 491 519 483 474 476 474 478
455 518 465 445 496 500 518 470 536
557 498 492 449 478 491 492 476 460
484 509 538 473 548 497 551 477 498
471 430 482 437 516 483 487 453 456
505 47开发者_如何学Python6 489 495 472 476 487 516 466
466 495 488 475 550 565 510 473 515
470 490 480 475 479 544 468 486 496
484 495 524 435 469 612 493 467 477
....
.... (several more rows)
....
511 471 529 553 539 501 477 474 494
via visual studio 2008 (in a c++ project) to a mathematical library LAPACK
.
Is it possible to pass the table in SQL Server to LAPACK
(via c++ in visual studio 2008) like a memory pointer, or store all the table in RAM, and LAPACK read memory or pointer to memory, but without writing to a file and reading it
Could you please suggest how to pass a table like this (maybe the location of table in memory, or something similar) to LAPACK?
(so I am able to do some computing with LAPACK of the table stored in SQL Server via visual studio 2008 c++ project)----EDIT---
@MarkD, As you said in your anwer could you please give an example of computing SVD with the idea in the example, using std::vector class ?
LAPACK requires the data sent to it, to be in a FORTRAN style (Column-order) array. You won't be able to pass the data directly from SQL to LAPACK but will need to read the data into a column-ordered contiguous memory array, and pass a pointer to the first element of the array to the LAPACK routine of interest.
There are many LAPACK wrappers for C/C++ out there that make this much easier.
Edit: just saw you are looking specifically for how to pass such an array. As I mentioned, there are many wrappers out there for doing this (just do a search for C/C++ LAPACK). An easy way to create your array is to use the std::vector class. You would then read the data in, column-by-column, adding the elements to your vector- So if you wanted to column-order the array you show in your exmaple, your vector would end up looking something like:
//Column 1 Column 2 Column 3 ... last element
[565 497 467 488 ... 526 491 516 466 ... 472 483 480 547 ... ... 494]
You would then pass the LAPACK routine of interest the memory location of the first element, eg:
&myVector[0]
This is possible using std::vector, as the standard ensures that a vector uses contiguous memory storage. The LAPACK routines all also require the size/dimensions of the matrix/vectors you are passing to it (so you'll need to calculate/specify these values for the function call).
If you can post the specific LAPACK routine you want to use, I can give a more thorough example.
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