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fix Compose's domain and some other minor issues in week 11 source #1

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fix Compose's domain and some other minor issues in week 11 source #1

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fc2a26b
fix access modifiers of evalAt and make TODOs in week 10 source
haki-1 May 12, 2020
b397b0d
Merge pull request #1 from fmi-lab/master
haki-1 May 20, 2020
3eea226
fix Compose's domain and some other minor issues in week 11 source
haki-1 May 20, 2020
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77 changes: 67 additions & 10 deletions 10.source.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -37,8 +37,30 @@ struct Positives : Set
Positives* clone() const override { return new Positives(); }
};

// @TODO Define the sets of positive, nonnegative numbers and sets of intervals
// of the form (a, b)
struct NonNegatives : Set
{
bool check(float x) const override { return x >= 0; }

NonNegatives* clone() const override { return new NonNegatives(); }
};

struct Interval : Set
{
const float a, b;

Interval(const float a, const float b) : a(a), b(b) {}

bool check(float x) const override { return a < x && b > x; }

Interval* clone() const override { return new Interval(*this); }
};

struct TanDomain : Set
{
bool check(float x) const override { return ceilf(x / (M_PI / 2)) != floorf(x / (M_PI / 2)) || (int)(x / (M_PI / 2)) % 2 == 0; }
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Това не е ли малко дълго като за един ред 😆.
Освен това е доста криптично написано с тези условия - наложи се да го разпиша формално, за да разбера какво прави 😆
Наистина, опитай по-простичко да го изразиш - трябва просто да провериш дали x е от вида ½π + kπ, т.е. дали уравнението ½π + kπ = x има цяло решение за k.
Как да провериш дали k излиза цяло… ще се сетиш сам. Hint: използвай fmod от cmath.

И като работиш с плаваща запетая, е хубаво да допускаш някаква епсилон грешка. Иначе, формално, това е коректно :)


TanDomain* clone() const override { return new TanDomain(); }
};

class RealFunc
{
Expand Down Expand Up @@ -75,13 +97,15 @@ struct Exponent : RealFunc
{
Exponent() : RealFunc{AllReals{}, "exp"} {}

protected:
virtual float evalAt(float x) override { return std::pow(E, x); }
};

struct Log : RealFunc
{
Log() : RealFunc{Positives{}, "log"} {}

protected:
float evalAt(float x) override { return std::log(x); }
};

Expand All @@ -90,6 +114,7 @@ struct BoyanFunction : RealFunc
int n;
int* myBigArr = new int[100]; // Illustration of the need of virtual d-tors

protected:
float evalAt(float x) override
{
n++;
Expand All @@ -110,6 +135,7 @@ struct Compose : RealFunc
{
}

protected:
float evalAt(float x) override
{
return f->safeEval(g->safeEval(x));
Expand All @@ -120,19 +146,27 @@ struct Sin : RealFunc
{
Sin() : RealFunc{AllReals{}, "sin"} {}

protected:
float evalAt(float x) override { return std::sin(x); }
};

// @TODO Define `struct Tan` and carefully construct its domain Set.
struct Tan : RealFunc
{
Tan() : RealFunc{TanDomain{}, "tan"} {}

protected:
float evalAt(float x) override { return std::tan(x); }
};

// @TODO Define `struct Pow` which raises `x` to a power, specified as a
// constructor argument.
struct Pow : RealFunc
{
const float exp;

// @TODO Define `struct Sum` which represents the sum of all functions in a
// given array.
Pow(const float exp) : RealFunc{Positives{}, "pow"}, exp(exp) {}

// @TODO Define global operators `*`, `+`, and `>>` which respectively act as
// multiplication, addition and composition of functions.
protected:
float evalAt(float x) override { return std::pow(x, exp); }
};

struct Sum : public RealFunc
{
Expand All @@ -143,11 +177,29 @@ struct Sum : public RealFunc
{
}

protected:
float evalAt(float x) override { return f->safeEval(x) + g->safeEval(x); }
};

struct Product : public RealFunc
{
RealFunc *f, *g;
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Хубаво е да са поне const, a най-добре и private - да не вземе някой да бърника :)


Product(RealFunc* f, RealFunc* g)
: RealFunc{Intersect{f->domain, g->domain}, "Product"}, f(f), g(g)
{
}

protected:
float evalAt(float x) override { return f->safeEval(x) * g->safeEval(x); }
};

Product operator*(RealFunc& a, RealFunc& b) { return {&a, &b}; }

Sum operator+(RealFunc& a, RealFunc& b) { return {&a, &b}; }

Compose operator>>(RealFunc& a, RealFunc& b) { return {&a, &b}; }

int main()
{
Log log;
Expand All @@ -160,4 +212,9 @@ int main()

RealFunc* base = &comp;
std::cout << base->safeEval(3) << std::endl;
}

// problem with Compose's defined domain - example
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Добре де, проблем има, а идея за решение 🤔?

Compose comp2{&log, &sin};
base = &comp2;
std::cout << base->safeEval(3 * M_PI / 2) << std::endl;
}
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