CODEWITHSUNDEEP
c++matlabdllstd
kiriloff
kiriloff

Reputation: 26333

Complementary vector using std::vector

I am writting in C++ an existing Matlab library. There is in Matlab a tilde operator, and ~vec is the binary vector with 1s where vec is zero and 0s elsewhere.

More precisely, I have these lines of code in Matlab

        allDepthIdx = [1:nVec]'; 
        goodIdx = allDepthIdx(~offVec);
        goodValues = vec(~offVec);

I am looking for an efficient way to find the indices goodIdx = allDepthIdx(~offVec);. I there a way, using std::vector, to find the list of indices which are in 1..nVec and not in offVec ?

Upvotes: 0

Views: 347

Answers (1)

kiriloff
kiriloff

Reputation: 26333

I came up with this solution, feel free to comment, or to propose yours !

        // First, I sort offVec
        std::sort(offVec.begin(), offVec.end());
        int k(0), idx(-1);

        std::vector<real32_T> goodDepthIdx;
        std::vector<real32_T> goodVal;

        // For j in 1..nVec, I check if j is in offVec
        for (int j = 0; j < nVec; j++)
        {
            k = 0;
            idx = offVec.at(k);

            // I go through offVec as long as element is strictly less than j
            while (idx < j)
            {
                idx = offVec.at(k++);
            }

            if (idx != j) // idx not in offElemsVec
            {
                goodDepthIdx.push_back(j); // Build vector with indices 
                                           // in 1..nVec not in offVec
                goodVal.push_back(vec.at(j)); // Build vector with values
                                           // at these indices
            }
        }

Upvotes: 0

Related Questions