GammaLib

The set_value method has been declared as const, and all members except of the nodes are now declared mutable.

Here some reading about the search algorithm: http://en.wikipedia.org/wiki/Binary_search

I’m not sure that the actual bisection code can be made much faster. I did some minor update, removing basically an unnecessary if statement, as shown below.

Before:

                int low  = 0;
                int high = nodes - 1;
                while ((high - low) > 1) {
                    int mid = (low+high) / 2;
                    if (m_node[mid] > value) {
                        high = mid;
                    }
                    else if (m_node[mid] <= value) {
                        low = mid;
                    }
                }
                m_inx_left = low;

After:

                int low  = 0;
                int high = nodes - 1;
                while ((high - low) > 1) {
                    int mid = (low+high) / 2;
                    if (m_node[mid] > value) {
                        high = mid;
                    }
                    else {
                        low = mid;
                    }
                }
                m_inx_left = low;

I also added caching of the last value, which should also speed up things.

I’m still need to work on the unit tests.

Unit tests have been added.