A simple C math vector library

Libvector is a simple library that allows you to work with math vectors in

Author: Vincenzo Corso <vincenzocorso99@gmail.com>

License: MIT (see LICENSE for details)

Installation

$ make setup
$ make
$ sudo make install

Include libvector.h header file at the top of the file ....

#include <libvector.h>

... and compile using -llibvector -lm

Usage

It's very simple and intuitive. These are some examples of usage.

Creating/Initialising new vectors

This library use a new type called vector_t. To create a new vector you can use create_vector or create_zero_vector specifying vector dimension. For example this code will create a vector in

vector_t vector = create_zero_vector(3); // 3 is vector dimension (R^3)
// create_zero_vector creates a null vector. To change components value use:
vector->components[0] = 4.4563; // Components goes from 0 to 2
vector->components[1] = 1;
vector->components[2] = -9.331113;
destroy_vector(&vector) // Don't forget to destroy the vector at the end

There is also a fastest way to initialise a vector:

vector_t vector = create_vector(5, (double []){1.0031, 2134.01, 333.333, 0.001, 3.4}); // This will create a vector in R^5.
destroy_vector(&vector); // Really. Don't forget this!

You can fill the components with the same value:

vector_t vector = create_zero_vector(3);
fill_vector(vector, 5.6); // Now vector is (5.6, 5.6, 5.6)
destroy_vector(&vector);

To increase/decrease vector dimension use vector_push and vector_pop:

vector_t vector = create_vector(4, (double []){1.1, 4.0, 3.2, 0.0});
// The following line add a new component in position 1
vector_push(vector, 5.6, 1); // Now vector is (1.1, 5.6, 4.0, 3.2, 0.0)
// The following line delete a component in position 3
vector_pop(vector, 3); // Now vector is (1.1, 5.6, 4.0, 0.0) 
destroy_vector(&vector);

Printing vectors

You can print a vector using both print_vector and printf_vector. For example:

vector_t vector = create_vector(4, (double []){0, 1, 0, 1});
// You can use print_vector to use default print format "%.2f "
print_vector(vector); // Print '0.00 1.00 0.00 1.00'
// .. Or you can use printf_vector to use a custom format
printf_vector(vector, "%.0f "); // Print '0 1 0 1'
destroy_vector(&vector);

Vector operations

Sum

vector_t vector1 = create_vector(4, (double []){1, 2, 3, 1});
vector_t vector2 = create_vector(4, (double []){3, 4, 1, 2});
vector_t sum = sum_vector(vector1, vector2);
printf_vector(sum, "%.0f "); // Print '4 6 4 3'

destroy_vectors(3, &vector1, &vector2, &sum); // Destroy many vectors at once

Dot product

vector_t vector1 = create_vector(4, (double []){1, 4, 1, 4});
vector_t vector2 = create_vector(4, (double []){3, 3, 1, 1});
double result = dot_product(vector1, vector2);
printf("Dot product: %.2f\n", result); // Calculate 1*3 + 4*3 + 1*1 + 4*1. Print 20.00

destroy_vectors(2, &vector1, &vector2);

Cross product

vector_t vector1 = create_vector(3, (double []){1, 4, 1});
vector_t vector2 = create_vector(3, (double []){3, 3, 1});
vector_t result = cross_product(vector1, vector2);
printf_vector(result, "%.0f "); // Print '1 -2 -9'

destroy_vector(3, &vector1, &vector2, &result);

Scalar multiplication

vector_t vector = create_vector(3, (double []){1, 4, 1});
vector_scalar_multiplication(vector, 2.1); // Overwrite the vector
print_vector(vector); // Print '2.1 8.4 2.1'

destroy_vector(&vector);

Scalar sum

vector_t vector = create_vector(3, (double []){4, 7, 2);
vector_add_scalar(vector, 1.1);
print_vector(vector); // Print '5.1 8.1 3.1'

destroy_vector(&vector);

Absolute value

vector_t vector = create_vector(3, (double []){-84.5, -67.1, 24.0});
vector_abs(vector);
print_vector(vector); // Print '84.5 67.1 24.0'

destroy_vector(&vector);

Vector normalitation and magnitude

vector_t vector = create_vector(3, (double []){1, 4, 1});
vector_normalize(vector); // Overwrite the vector
print_vector(vector); // Print '0.24 0.94 0.24'
double magnitude = vector_magnitude(vector);
printf("Magnitude: %.2f\n", magnitude); // Print 1.00

destroy_vector(&vector);

Vector properties

You can use these useful functions to show vector properties

vector_t vector1 = create_vector(3, (double []){5, 3, 2});
vector_t vector2 = create_vector(3, (double []){10, 6, 4});

int min_index = min_vector_component(vector1);
int max_index = max_vector_component(vector1);
printf("min_index: %d | max_index: %d\n", min_index, max_index); // Print '2 0'

int result1 = is_zero_vector(vector2); // Check if all components are equal to zero
int result2 = is_parallel_to(vector2, vector1); // Check if vector2 is parallel to vector1
int result3 = is_perpendicular_to(vector2, vector1); // Check if vector2 is perpendicular to vector1
printf("result1: %d | result2: %d | result3: %d\n", result1, result2, result3); // Print '0 1 0'

double angle = vector_angle(vector1, vector2); // Calculate the angle in radians between vector1 and vector2
printf("angle: %.2f\n", angle); // Printf '0.00' because the two vectors are parallel

destroy_vector(2, &vector1, &vector2);

Other stuff

If you want to access to vector dimension or single vector component:

vector_t vector1 = create_vector(4, (double []){4, 4, 1, 2});
printf("%u %.0f\n", vector1->dimension, vector1->component[3]); // Print '4 2'
destroy_vector(&vector1);

If you want to duplicate an existing vector use copy_vector:

vector_t vector1 = create_vector(4, (double []){2, 4, 5, 1});
vector_t vector2 = copy_vector(vector1);
print_vector(vector2); // Print '2.00 4.00 5.00 1.00'
destroy_vectors(2, &vector1, &vector2);

Memory leaks

Pay attention to not change vector rvalue before destroying it.

vector_t vector1 = create_zero_vector(5);
vector1 = create_vector(2, (double []){1, 2});
destroy_vector(&vector1); // Old vector1 is still in memory (Memory leaks)