unit_si.cc

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/*!
 *
 * Copyright (C) 2015 Technical University of Liberec.  All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 3 as published by the
 * Free Software Foundation. (http://www.gnu.org/licenses/gpl-3.0.en.html)
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * 
 * @file    unit_si.cc
 * @brief   
 */

#include <sstream>

#include "fields/unit_si.hh"
#include "system/asserts.hh"


using namespace std;


UnitSI::UnitSI() {
    exponents_.resize(UnitSI::n_base_units);
    std::fill(exponents_.begin(), exponents_.end(), 0);
    undef_ = true;
}

UnitSI & UnitSI::N() {
    static UnitSI unit = UnitSI().m().kg().s(-2);
    return unit;
}

UnitSI & UnitSI::J() {
    static UnitSI unit = UnitSI().m(2).kg().s(-2);
    return unit;
}

UnitSI & UnitSI::W() {
    static UnitSI unit = UnitSI().m(2).kg().s(-3);
    return unit;
}

UnitSI & UnitSI::Pa() {
    static UnitSI unit = UnitSI().m(-1).kg().s(-2);
    return unit;
}

UnitSI & UnitSI::dimensionless() {
    static UnitSI unit = UnitSI().m(0);
    return unit;
}

UnitSI & UnitSI::one() {
    return dimensionless();
}

UnitSI & UnitSI::m(int exp) {
    exponents_[UnitSI::order_m] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::kg(int exp) {
    exponents_[UnitSI::order_kg] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::s(int exp) {
    exponents_[UnitSI::order_s] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::A(int exp) {
    exponents_[UnitSI::order_A] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::K(int exp) {
    exponents_[UnitSI::order_K] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::mol(int exp)  {
    exponents_[UnitSI::order_mol] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::cd(int exp) {
    exponents_[UnitSI::order_cd] = exp;
    undef_ = false;
    return *this;
}

UnitSI & UnitSI::md(int exp) {
    exponents_[UnitSI::order_md] = exp;
    undef_ = false;
    return *this;
}






std::string UnitSI::format_latex() const {
    OutputFormat form;
    form.exp_open="^{";
    form.exp_close="}";
    form.delimiter="";
    return format(form);
}



std::string UnitSI::format_text() const {
    OutputFormat form;
    form.exp_open="(";
    form.exp_close=")";
    form.delimiter=".";
    return format(form);
}


// Symbols for base SI units.
const std::string &UnitSI::unit_symbol(unsigned int idx) {
    static std::vector<std::string> unit_symbols={"m","md","kg","s","A","K","mol","cd" };
    return unit_symbols[idx];
}



std::string UnitSI::format(OutputFormat form) const {
    ASSERT(is_def()).error("UnitSI object must be defined!");

    std::stringstream output;

    // format of meter (can be m^{n} or m^{n-d})
    if (exponents_[ UnitSI::order_m ] || exponents_[ UnitSI::order_md ]) {
        output << unit_symbol( UnitSI::order_m );
        if (exponents_[ UnitSI::order_m ]!=1 || exponents_[ UnitSI::order_md ]) {
            output << form.exp_open;
            if (exponents_[ UnitSI::order_m ]) {
                output << exponents_[ UnitSI::order_m ];
                if (exponents_[ UnitSI::order_md ]>0) output << "+";
            }
            if (exponents_[ UnitSI::order_md ]) {
                if (exponents_[ UnitSI::order_md ]==-1) output << "-";
                else if (exponents_[ UnitSI::order_md ]!=1) output << exponents_[ UnitSI::order_md ];
                output << "d"; // Use 'd' for dimension in exponent, converting m^x md^y to m^(x+yd)
            }
            output << form.exp_close;
        }
    }

    // format of other units
    for (unsigned int i=2; i<UnitSI::n_base_units; i++)
        if (exponents_[i]) {
            if (output.str().size() > 0) output << form.delimiter;
            output << unit_symbol(i);
            if (exponents_[i] != 1) output <<  form.exp_open << exponents_[i] << form.exp_close;
        }

    if (output.str().size()==0) { //dimensionless quantity, contains only "$["
        output << "-";
    }

    return output.str();
}


std::string UnitSI::json() const {
    stringstream ss;
    ss << "{ ";
    for(unsigned int i=0; i < n_base_units; i++ ) {
        if (i!=0) ss << ", ";
        ss << string("\"")
           << unit_symbol(i)
           << "\" : "
           << exponents_[i];
    }
    ss << " }";
    return ss.str();
}

void UnitSI::undef(bool val) {
    undef_ = val;
}

bool UnitSI::is_def() const {
    return !undef_;
}


UnitSI operator *(const UnitSI &a, const UnitSI &b) {
    UnitSI tmp;

    if (a.is_def() && b.is_def()) {
        tmp.undef_ = false;
        for (unsigned int i=0; i<7; i++) {
            tmp.exponents_[i] = a.exponents_[i] + b.exponents_[i];
        }
    }

    return tmp;
}

UnitSI operator /(const UnitSI &a, const UnitSI &b) {
    UnitSI tmp;

    if (a.is_def() && b.is_def()) {
        tmp.undef_ = false;
        for (unsigned int i=0; i<7; i++) {
            tmp.exponents_[i] = a.exponents_[i] - b.exponents_[i];
        }
    }

    return tmp;
}