[Coin-discuss] CoinPackedMatrix: problems appending matrices

[Joerg Herbers]

I have had problems (bottom-)appending column-ordered matrices to row-ordered matrices (using CoinPackedMatrix::bottomAppendPackedMatrix) and (right-)appending row-ordered matrices to column-ordered matrices (using CoinPackedMatrix::rightAppendPackedMatrix). In both cases, CoinPackedMatrix::majorAppendOrthoOrdered is called, yielding matrices which don't look correct in terms of major dimensions. Adding the two lines

   majorDim_ += matrix.minorDim_;
   size_ += matrix.size_;

to the end of majorAppendOrthoOrdered() corrects this problem in my implementation.

Additionally, there seems to be an indexing problem in a for loop in the same function (line 1330 of CoinPackedMatrix.cpp) which led to a crash in my application. The code segment reads as

     for (i = 0; i < matrix.minorDim_ - 1; ++i) {
       start_[i+1] = start_[i] + CoinLengthWithExtra(orthoLength[i], extra_gap);
     }

meaning that the start_ array is only adapted up to a value of i+1==matrix.minorDim-1. However, the implementation of CoinPackedMatrix obviously assumes that start_[matrix.minorDim_] is filled with the size of the index vector. If I change the conditional part of the for loop to "i < matrix.minorDim_", everything works fine.

Could you check if I'm right? Or did I miss something?

Thanks in advance,
Jörg




Dr. Jörg Herbers
Geschäftsbereich Systeme Airport
INFORM GmbH, Pascalstraße 23, 52076 Aachen, Germany
Telefon: (+49) 2408 9456-24, Fax: (+49) 2408 9456-25
E-Mail: joerg.herbers at inform-ac.com, Web: http://www.inform-ac.com