Hi Gábor, On Wed, 11 Jul 2018, SZEDER Gábor wrote: > > diff --git a/linear-assignment.c b/linear-assignment.c > > new file mode 100644 > > index 000000000..0b0344b5f > > --- /dev/null > > +++ b/linear-assignment.c > > @@ -0,0 +1,203 @@ > > +/* > > + * Based on: Jonker, R., & Volgenant, A. (1987). A shortest augmenting path > > + * algorithm for dense and sparse linear assignment problems. Computing, > > + * 38(4), 325-340. > > + */ > > +#include "cache.h" > > +#include "linear-assignment.h" > > + > > +#define COST(column, row) cost[(column) + column_count * (row)] > > + > > +/* > > + * The parameter `cost` is the cost matrix: the cost to assign column j to row > > + * i is `cost[j + column_count * i]. > > + */ > > +void compute_assignment(int column_count, int row_count, int *cost, > > + int *column2row, int *row2column) > > +{ > > [...] > > > +update: > > + /* updating of the column pieces */ > > + for (k = 0; k < last; k++) { > > + int j1 = col[k]; > > + v[j1] += d[j1] - min; > > + } > > + > > + /* augmentation */ > > + do { > > + if (j < 0) > > + BUG("negative j: %d", j); > > + i = pred[j]; > > + column2row[j] = i; > > + k = j; > > + j = row2column[i]; > > + row2column[i] = k; > > Coccinelle suggests using SWAP(j, row2column[i]) instead of the last > three lines above. > It's more idiomatic, and it avoids (ab)using the 'k' variable > (elsewhere used as loop variable) as a temporary variable. Good point. I audited the rest of the code in this file, and there are no more swap operations. Thanks, Dscho