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SubMat.h

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/*
    File:           SubMat.h

    Function:       Defines a scatter-gather matrix, i.e., a submatrix of another matrix.
                    
    Author(s):      Andrew Willmott

    Copyright:      (c) 1995-2000, Andrew Willmott
 */

#ifndef __SubMat__
#define __SubMat__

#include "vl/VL.h"
#include "vl/SubVec.h"

// --- SubMat Class -----------------------------------------------------------

class TMat;
class TVec;

class TSubMat
{
public:
    
    // Constructors
    
                        TSubMat(Int m, Int n, Int span, TMReal data[]);
                        TSubMat(const TSubMat &m);          
    
    // Accessor functions
    
    Int                 Rows() const { return rows; };
    Int                 Cols() const { return cols; };

    inline TMVec        operator [] (Int i) const;        

    inline TMReal       &Elt(Int i, Int j);
    inline TMReal       Elt(Int i, Int j) const;

    // Assignment operators
    
    TSubMat             &operator = (const TSubMat &m); // Assignment of a matrix
    TSubMat             &operator = (const TMat &m);    

    Int                 rows;
    Int                 cols;
    Int                 span;
    TMReal              *data; 
};


// --- Submatrix functions ----------------------------------------------------
    
TSubMat     sub(const TMat &m, Int top, Int left, Int height, Int width);
TSubMat     sub(const TMat &m, Int rows, Int cols);
TMSubVec    row(const TMat &m, Int i);
TMSubVec    col(const TMat &m, Int i);
TMSubVec    diag(const TMat &m, Int diagNum = 0);
//  -i = diag. starting on row i, +i = diag. starting on col i

TSubMat     sub(const TSubMat &m, Int top, Int left, Int height, Int width);
TSubMat     sub(const TSubMat &m, Int rows, Int cols);
TMSubVec    row(const TSubMat &m, Int i);
TMSubVec    col(const TSubMat &m, Int i);
TMSubVec    diag(const TSubMat &m, Int diagNum = 0);

// --- SubMat Inlines ---------------------------------------------------------


#include "vl/Vec.h"

inline TMVec TSubMat::operator [] (Int i) const
{
    CheckRange(i, 0, Rows(), "(SubMat::(i)) index out of range");
    return(TMVec(cols, data + i * span));
}

inline TMReal &TSubMat::Elt(Int i, Int j)
{
    CheckRange(i, 0, Rows(), "(SubMat::(i,j)) i index out of range");
    CheckRange(j, 0, Cols(), "(SubMat::(i,j)) j index out of range");
    return(data[i * span + j]);
}

inline TMReal TSubMat::Elt(Int i, Int j) const
{
    CheckRange(i, 0, Rows(), "(SubMat::(i,j)) i index out of range");
    CheckRange(j, 0, Cols(), "(SubMat::(i,j)) j index out of range");
    return(data[i * span + j]);
}

#endif

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