Atomic Vector Sparsity Patterns Example

atomic_four_vector_jac_sparsity.cpp

@(@\newcommand{\W}[1]{ \; #1 \; } \newcommand{\R}[1]{ {\rm #1} } \newcommand{\B}[1]{ {\bf #1} } \newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} } \newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} } \newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} } \newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }@)@This is cppad-20221105 documentation. Here is a link to its current documentation . Atomic Vector Sparsity Patterns Example
f(u, v)
For this example, @(@ f : \B{R}^{3m} \rightarrow \B{R}^m @)@ is defined by @(@ f(u, v, w) = - u * v * w @)@. where u , v , and w are in @(@ \B{R}^m @)@.

Source


# include <cppad/cppad.hpp>
# include <cppad/example/atomic_four/vector/vector.hpp>
bool jac_sparsity(void)
{   bool ok = true;
    using CppAD::NearEqual;
    using CppAD::AD;
    //
    // vec_op
    // atomic vector_op object
    CppAD::atomic_vector<double> vec_op("atomic_vector");
    //
    // m
    // size of u, v, and w
    size_t m = 6;
    //
    // n
    size_t n = 3 * m;
    //
    // mul_op, neg_op
    typedef CppAD::atomic_vector<double>::op_enum_t op_enum_t;
    op_enum_t mul_op = CppAD::atomic_vector<double>::mul_enum;
    op_enum_t neg_op = CppAD::atomic_vector<double>::neg_enum;
    // -----------------------------------------------------------------------
    // Record f(u, v, w) = - u * v * w
    // -----------------------------------------------------------------------
    // Independent variable vector
    CPPAD_TESTVECTOR( CppAD::AD<double> ) auvw(n);
    for(size_t j = 0; j < n; ++j)
        auvw[j] = AD<double>(1 + j);
    CppAD::Independent(auvw);
    //
    // au, av, aw
    CPPAD_TESTVECTOR( CppAD::AD<double> ) au(m), av(m), aw(m);
    for(size_t i = 0; i < m; ++i)
    {   au[i] = auvw[0 * m + i];
        av[i] = auvw[1 * m + i];
        aw[i] = auvw[2 * m + i];
    }
    //
    // ax = (au, av)
    CPPAD_TESTVECTOR( CppAD::AD<double> ) ax(2 * m);
    for(size_t i = 0; i < m; ++i)
    {   ax[i]     = au[i];
        ax[m + i] = av[i];
    }
    //
    // ay = u * v
    CPPAD_TESTVECTOR( CppAD::AD<double> ) ay(m);
    vec_op(mul_op, ax, ay);
    //
    // ax = (ay, aw)
    for(size_t i = 0; i < m; ++i)
    {   ax[i]     = ay[i];
        ax[m + i] = aw[i];
    }
    //
    // az = ay * w
    CPPAD_TESTVECTOR( CppAD::AD<double> ) az(m);
    vec_op(mul_op, ax, az);
    //
    // ay = - az
    vec_op(neg_op, az, ay);
    //
    // f
    CppAD::ADFun<double> f(auvw, ay);
    //
    // size_vector, sparsity_pattern
    typedef CPPAD_TESTVECTOR(size_t) size_vector;
    typedef CppAD::sparse_rc<size_vector> sparsity_pattern;
    // -----------------------------------------------------------------------
    // Jacobian sparsity
    // -----------------------------------------------------------------------
    for(size_t direction = 0; direction < 2; ++direction)
    {   sparsity_pattern pattern_out;
        bool transpose     = false;
        bool dependency    = false;
        bool internal_bool = false;
        if( direction == 0 )
        {   // Forward direction
            //
            // pattern_in
            // sparsity pattern for identity matrix
            sparsity_pattern pattern_in(n, n, n);
            for(size_t k = 0; k < n; ++k)
                pattern_in.set(k, k, k);
            //
            // pattern_out
            f.for_jac_sparsity(
                pattern_in, transpose, dependency, internal_bool, pattern_out
            );
        }
        else
        {   // Reverse direction
            //
            // pattern_in
            // sparsity pattern for identity matrix
            sparsity_pattern pattern_in(m, m, m);
            for(size_t k = 0; k < m; ++k)
                pattern_in.set(k, k, k);
            //
            // pattern_out
            f.rev_jac_sparsity(
                pattern_in, transpose, dependency, internal_bool, pattern_out
            );
        }
        //
        // ok
        ok &= pattern_out.nnz() == 3 * m;
        ok &= pattern_out.nr()  == m;
        ok &= pattern_out.nc()  == n;
        //
        // row, col, row_major
        const size_vector& row = pattern_out.row();
        const size_vector& col = pattern_out.col();
        size_vector row_major  = pattern_out.row_major();
        //
        // ok
        size_t ell = 0;
        for(size_t i = 0; i < m; ++i)
        {   // first non-zero in row i
            size_t k = row_major[ell++];
            ok      &= row[k] == i;
            ok      &= col[k] == i;
            // second non-zero in row i
            k        = row_major[ell++];
            ok      &= row[k] == i;
            ok      &= col[k] == m + i;
            // third non-zero in row i
            k        = row_major[ell++];
            ok      &= row[k] == i;
            ok      &= col[k] == 2 * m + i;
        }
    }
    //
    return ok;
}

Input File: example/atomic_four/vector/jac_sparsity.cpp