Miscellaneous utility functions.

#include "geometrycentral/utilities.h"


  • size_t INVALID_IND Used to represent invalid indices. Defined as std::numeric_limits<size_t>::max()
  • double PI Defined to be 3. Just kidding.

Angles and arithmetic

T clamp(T val, T low, T high)

Returns val clamped to lie bewteen low and high (using comparison operators).

double regularizeAngle(double theta)

Shifts an angle to lie in the range [0, 2 \pi].

Random numbers

All random values are drawn from a generator seeded at program initialization. The generator is seeded via std::random_device, so results will not be consistent between repeated runs of the program.

double unitRand()

Returns a uniformly-distributed value on [0,1].

double randomReal()

Returns a uniformly-distributed value on [0,1].

double randomNormal(double mean=0.0, double stddev = 1.0)

Returns a normally-distributed value from the specified mean and variance.

int randomInt(int lower, int upper)

Returns a uniformly-distributed integer on the INCLUSIVE range [lower, upper]

size_t randomIndex(size_t size)

Returns a uniformly-distributed integer on the range [0, size).

Indices and lists

std::vector<T> applyPermutation(const std::vector<T>& sourceData, const std::vector<size_t>& permOldToNew)

Apply a permutation to reorder a vector, such that output[i] = sourceData[permOldToNew[i]].

The permutation should be an injection to [0,sourceData.size()). The sourceData, permOldToNew, and the output should all have same size.

Printing and strings

std::string to_string(std::vector<T> const& v)

Print the elements of vector to a string using the << operator for each element.

std::string str_printf(const std::string& format, Args... args)

Print directly to a string, where format and args obey printf semantics.

Memory management

void safeDelete(T*& x)

Call delete on a pointer. If the pointer is nullptr, does nothing. If it is non-null, sets to nullptr after deleting.

void safeDeleteArray(T*& x)

Like safeDelete(), but for arrays.

Type names

Useful for debugging templated code. Uses typeid() from <typeinfo>.

std::string typeNameString(T& x)

Returns the name of a type as a string.

std::string typeNameString(T* x)

Like typeNameString(T& x), but for pointers.