From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,e9cc8b90e75b064d X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-05-23 07:15:04 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!arclight.uoregon.edu!wn13feed!worldnet.att.net!204.127.198.203!attbi_feed3!attbi.com!rwcrnsc53.POSTED!not-for-mail From: "P S Norby" Newsgroups: comp.lang.ada References: Subject: Re: Slice from a matrix? X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Message-ID: NNTP-Posting-Host: 12.237.80.125 X-Complaints-To: abuse@attbi.com X-Trace: rwcrnsc53 1053699303 12.237.80.125 (Fri, 23 May 2003 14:15:03 GMT) NNTP-Posting-Date: Fri, 23 May 2003 14:15:03 GMT Organization: AT&T Broadband Date: Fri, 23 May 2003 14:15:03 GMT Xref: archiver1.google.com comp.lang.ada:37691 Date: 2003-05-23T14:15:03+00:00 List-Id: "David C. Hoos" wrote in message news:Cmnza.38775$l66.3829@fe10.atl2.webusenet.com... > > "Harald Schmidt" wrote in message > news:BAF3B30D.3023%harald.schmidt@anobject.net... > > Hi, > > > > I got a generic matrix / vector package like this: > > > > Generic > > rows : positive; > > cols : positive; > > item_type is digits <>; > > Package matrix is > > type vector_type is array (positive range <>) of item_type; > > type matrix_type is array (positive range <>, > > positive range <>) of item_type; > > subtype col_vector is vector_type(1..cols); > > subtype row_vector is vector_type(1..rows); > > subtype matrix is matrix_type(1..rows, 1..cols); > > ... > > End matrix; > > > > Then I have three Put procedures, one for matrix, one for row_vector, and > > one for col_vector. > > > > My question is how to get a slice from a matrix which I can convert to a > > col_vector which does the printing? > > > > Things like... > > > > PUT (col_vector(M (1, 1..3))); > > > > doesn't work. > > > > I don't want to copy code for the printing routines. > Since slices in ada can only be taken from one-dimensional arrays, you > would need to declare your matrix as an array of vectors. > Individual elements are then accessed by matrix (m}{n}. > The trouble then is that you can either have rows of columns, in which case you can take a slice of a column, but not a slice of a row... or you can have columns of rows, in which case you can take a slice of a row, but not a slice of a column. The col_vector and row_vector are not subtypes of matrix_type. > Incidentally, shouldn't a vector which is indexed by row be a column vector, > and a vector which is indexed by column be a row vector? Yes. Might want to make them type-safe. My simple solution would be to have a "Put_Item (item : in item_type);" routine (add other parameters as desired), then declare something like procedure Put_Column (Mat : in Matrix_type; in_col : in cols; from_row, to_row: in rows); and similalry to print rows or matrix. Your "PUT (col_vector(M (1, 1..3)));" becomes Put_Column (M, 1, 1, 3); or Put_Column (Mat => M, in_col => 1, From_row =>1, to_row => 3); if you prefer named notation. These "put" routines could be in your generic or elsewhere.