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make matrix multiplication do immediate evaluation; add lazyMul() for the old behaviour

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some reorganization, especially in MatrixStorage
start playing with loop unrolling, always_inline, and __restrict__
This commit is contained in:
Benoit Jacob
2007-09-29 08:28:36 +00:00
parent 51e29ae4bd
commit ee63e15e2c
10 changed files with 113 additions and 50 deletions
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18
doc/tutorial.cpp
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@@ -29,23 +29,5 @@ int main(int, char **)
cout << "Row 0 of m2, written as a column vector, is:" << endl << m2.row(0) << endl;
cout << "Column 1 of m2 is:" << endl << m2.col(1) << endl;
cout << "The matrix m2 with row 0 and column 1 removed is:" << endl << m2.minor(0,1) << endl;
cout << endl << "Now let us study a tricky issue." << endl;
cout << "Recall that the matrix product m*m is:" << endl << m*m << endl;
cout << "We want to store that into m, i.e. do \"m = m * m;\"" << endl;
cout << "Here we must be very careful. For if we do \"m = m * m;\"," << endl
<< "the matrix m becomes" << endl;
EiMatrix<double,2,2> m_save = m;
m = m * m; // the bogus operation
cout << m << "," << endl;
cout << "which is not what was wanted!" << endl
<< "Explanation: because of the way expression templates work, the matrix m gets" << endl
<< "overwritten _while_ the matrix product m * m is being computed." << endl
<< "This is the counterpart of eliminating temporary objects!" << endl
<< "Anyway, if you want to store m * m into m, you can do this:" << endl
<< " m = (m * m).eval();" << endl;
m = m_save;
m = (m * m).eval();
cout << "And m is now:" << endl << m << endl << "as was expected." << endl;
return 0;
}