From 53ec4c3e9088d3acaa6a0358c792358796ecde5b Mon Sep 17 00:00:00 2001
From: Jesper Andersson <jesper@fmrib.ox.ac.uk>
Date: Mon, 10 Sep 2007 14:54:53 +0000
Subject: [PATCH] Added transpose ( .t() ) to SpMat class
---
SpMat.h | 65 ++++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 46 insertions(+), 19 deletions(-)
diff --git a/SpMat.h b/SpMat.h
index 57823ea..32a37a7 100644
--- a/SpMat.h
+++ b/SpMat.h
@@ -11,14 +11,6 @@
// for example inserting elements in a random order may be
// a bit slow.
//
-// You will notice that some "obvious" functionality like e.g.
-// transpose is missing. Instead I have supplied functionality
-// like A.trans_mult(x) which is equivalent to A.t()*x in NEWMAT
-// lingo. The reason for this is partly to supply an api that is
-// consistent with that expected by IML++. But more so because I
-// believe that when a matrix is unwieldily enough to warrant
-// the use of a sparse matrix class, then one should not attempt
-// to represent both the matrix and its transpose.
//
// Jesper Andersson, FMRIB Image Analysis Group
//
@@ -134,6 +126,8 @@ public:
SpMat<T>& operator&=(const SpMat<T>& bh); // Vert concat below
const SpMat<T> TransMultSelf() const {return(TransMult(*this));} // Returns transpose(*this)*(*this)
+
+ const SpMat<T> t() const; // Returns transpose(*this). Avoid, if at all possible.
friend class Accumulator<T>;
@@ -146,18 +140,18 @@ public:
unsigned int miter = 200,
boost::shared_ptr<Preconditioner<T> > C = boost::shared_ptr<Preconditioner<T> >()) const;
-NEWMAT::ReturnMatrix SolveForx(const NEWMAT::ColumnVector& b,
- MatrixType type,
- double tol,
- unsigned int miter,
- const NEWMAT::ColumnVector& x_init) const;
+ NEWMAT::ReturnMatrix SolveForx(const NEWMAT::ColumnVector& b,
+ MatrixType type,
+ double tol,
+ unsigned int miter,
+ const NEWMAT::ColumnVector& x_init) const;
-NEWMAT::ReturnMatrix SolveForx(const NEWMAT::ColumnVector& b,
- MatrixType type,
- double tol,
- unsigned int miter,
- boost::shared_ptr<Preconditioner<T> > C,
- const NEWMAT::ColumnVector& x_init) const;
+ NEWMAT::ReturnMatrix SolveForx(const NEWMAT::ColumnVector& b,
+ MatrixType type,
+ double tol,
+ unsigned int miter,
+ boost::shared_ptr<Preconditioner<T> > C,
+ const NEWMAT::ColumnVector& x_init) const;
private:
unsigned int _m;
@@ -461,6 +455,39 @@ NEWMAT::ReturnMatrix SpMat<T>::SolveForx(const NEWMAT::ColumnVector&
x.Release();
return(x);
}
+
+/////////////////////////////////////////////////////////////////////
+//
+// Returns a sparse matrix that is the transpose of *this
+//
+/////////////////////////////////////////////////////////////////////
+
+template<class T>
+const SpMat<T> SpMat<T>::t() const
+{
+ SpMat<T> t_mat(_n,_m);
+ Accumulator<T> t_col(_n);
+ for (unsigned int new_col=0; new_col<_m; new_col++) { // For all columns of transposed matrix
+ t_col.Reset();
+ for (unsigned int old_col=0; old_col<_n; old_col++) { // Search old colums for row-index corresponding to new_col
+ int pos = 0;
+ if (found(_ri[old_col],new_col,pos)) {
+ t_col(old_col) = _val[old_col][pos];
+ }
+ }
+ t_mat._ri[new_col].resize(t_col.NO());
+ t_mat._val[new_col].resize(t_col.NO());
+ std::vector<unsigned int>& t_mat_ri = t_mat._ri[new_col];
+ std::vector<T>& t_mat_val = t_mat._val[new_col];
+ for (unsigned int i=0; i<t_col.NO(); i++) {
+ t_mat_ri[i] = t_col.ri(i);
+ t_mat_val[i] = t_col.val(i);
+ }
+ t_mat._nz += t_col.NO();
+ }
+ return(t_mat);
+}
+
/////////////////////////////////////////////////////////////////////
//
// Returns value at position i,j (one offset)
--
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