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bug #1271: add SparseMatrix::coeffs() methods returning a 1D view of the non zero coefficients.

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This commit is contained in:
Gael Guennebaud 2016-08-29 12:06:37 +02:00
parent a93e354d92
commit 7e029d1d6e
3 changed files with 38 additions and 0 deletions
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19
Eigen/src/SparseCore/SparseCompressedBase.h
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@ -106,6 +106,25 @@ class SparseCompressedBase
/** \returns whether \c *this is in compressed form. */
inline bool isCompressed() const { return innerNonZeroPtr()==0; }
/** \returns a read-only view of the stored coefficients as a 1D array expression.
*
* \warning this method is for \b compressed \b storage \b only, and it will trigger an assertion otherwise.
*
* \sa valuePtr(), isCompressed() */
const Map<const Array<Scalar,Dynamic,1> > coeffs() const { eigen_assert(isCompressed()); return Array<Scalar,Dynamic,1>::Map(valuePtr(),nonZeros()); }
/** \returns a read-write view of the stored coefficients as a 1D array expression
*
* \warning this method is for \b compressed \b storage \b only, and it will trigger an assertion otherwise.
*
* Here is an example:
* \include SparseMatrix_coeffs.cpp
* and the output is:
* \include SparseMatrix_coeffs.out
*
* \sa valuePtr(), isCompressed() */
Map<Array<Scalar,Dynamic,1> > coeffs() { eigen_assert(isCompressed()); return Array<Scalar,Dynamic,1>::Map(valuePtr(),nonZeros()); }
protected:
/** Default constructor. Do nothing. */
SparseCompressedBase() {}

9
doc/snippets/SparseMatrix_coeffs.cpp Normal file
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@ -0,0 +1,9 @@
SparseMatrix<double> A(3,3);
A.insert(1,2) = 0;
A.insert(0,1) = 1;
A.insert(2,0) = 2;
A.makeCompressed();
cout << "The matrix A is:" << endl << MatrixXd(A) << endl;
cout << "it has " << A.nonZeros() << " stored non zero coefficients that are: " << A.coeffs().transpose() << endl;
A.coeffs() += 10;
cout << "After adding 10 to every stored non zero coefficient, the matrix A is:" << endl << MatrixXd(A) << endl;

10
test/sparse_basic.cpp
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@ -207,6 +207,16 @@ template<typename SparseMatrixType> void sparse_basic(const SparseMatrixType& re
VERIFY_IS_APPROX((m1 = m1.transpose()), (refM1 = refM1.transpose().eval()));
VERIFY_IS_APPROX((m1 = -m1.transpose()), (refM1 = -refM1.transpose().eval()));
VERIFY_IS_APPROX((m1 += -m1), (refM1 += -refM1));
if(m1.isCompressed())
{
VERIFY_IS_APPROX(m1.coeffs().sum(), m1.sum());
m1.coeffs() += s1;
for(Index j = 0; j<m1.outerSize(); ++j)
for(typename SparseMatrixType::InnerIterator it(m1,j); it; ++it)
refM1(it.row(), it.col()) += s1;
VERIFY_IS_APPROX(m1, refM1);
}
}
// test transpose