expression_parser.h

/*
 * Parser/evaluator for the analytic expressions given by the user:
 *  - vector M(x, y, z, regions): initial magnetization
 *  - vector B(t): space-independent applied field, or
 *  - scalar A(t): amplitude of space-dependent applied field, and
 *  - vector f(x, y, z): space-dependent part of the applied field.
 */
 
#ifndef expression_parser_h
#define expression_parser_h
 
#include <duktape.h>
#include <string>
 
#include <eigen3/Eigen/Dense>
 
class ExpressionParser
    {
public:
    ExpressionParser();
    ExpressionParser(const ExpressionParser &) = delete;
    ExpressionParser &operator=(const ExpressionParser &) = delete;
    ~ExpressionParser();
 
    void set_function(const std::string &js_function) const;
 
    void set_expressions(const std::string &parameters, const std::string &expr_x,
                         const std::string &expr_y, const std::string &expr_z);
 
    int parameter_count() const { return duk_get_length(ctx, -1); }
 
    double get_scalar(double arg) const;
 
    Eigen::Vector3d get_vector(double arg) const;
 
    Eigen::Vector3d get_vector(const Eigen::Ref<Eigen::Vector3d> arg) const;
 
    Eigen::Vector3d get_vector(const Eigen::Ref<Eigen::Vector3d> position,
            const std::vector<std::string> &regions) const;
 
private:
    void die_if_error(duk_int_t err) const;
 
    double get_vector_component(int idx) const;
 
    Eigen::Vector3d compute_vector(int argument_count) const;
 
    duk_context *ctx;
    };
 
#endif /* expression_parser_h */