Cartesian 3D Vector Lib

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A simple vector library written in plain C for educational purpose.

Introduction

This library is written in hope to simplify the coding process for non-professional vector computation.

This library should not be used for industrial or scientific use due to the limited precision and performance; Complex number is not supported either.

Usage

  1. You may copy the files in ./include to your project directory and compile it seperately;

  2. You may generate a single head file vector.h for your project:

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    $ make single

    This generate a single head file in the project root directory ./. Copy the ./vector.h to your project and include it.

Example

This is a brief demonstration on the commonly used functions’ usage. The output of each statement follows in comments.

Several practical examples are available in ./example.

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#include "include/vector.h"

int main(int argc, char const *argv[])
{
// Initialize vectors

vector A = vecSet(1.0, 2.0, 0.0);
vector B = vecSet(0.0, 1.0, 3.0);


// vecPrint() pretty print the vector
// in the form of <x,y,z> |modulus|

printf("Vector A,B\n");
vecPrint(A); // < 1.00, 2.00, 0.00> | 2.24|
vecnPrint(B, 4); // < 0.0000, 1.0000, 3.0000> | 3.1623|

// Arithmetic operations
// The comming statements demonstarte
// 1. Vector Addtion
// 2. Vector Subtraction
// 3. Vector Cross Product
// 4. Vector Dot Product
// 5. Vector Scalar Product

printf("\nADD, SUB, CRX, DOT, SCL\n");
vecPrint(vecAdd(A, B)); // < 1.00, 3.00, 3.00> | 4.36|
vecPrint(vecSub(A, B)); // < 1.00, 1.00,-3.00> | 3.32|
vecPrint(vecCrx(A, B)); // < 6.00,-3.00, 1.00> | 6.78|
printf("% .2f\n",vecDot(A, B)); // 2.00
vecPrint(vecScl(A, 4.0)); // < 8.00, 0.00, 0.00> | 8.00|

// Find unit vector

printf("\nUnit A,B\n");
vecPrint(vecUnit(A)); // < 0.45, 0.89, 0.00> | 2.24|
vecPrint(vecUnit(B)); // < 0.00, 0.32, 0.95> | 3.16|

// Take negative

printf("\nNEG A,B\n");
vecPrint(vecNeg(A)); // <-1.00,-2.00,-0.00> | 2.24|
vecPrint(vecNeg(B)); // <-0.00,-1.00,-3.00> | 3.16|

// Take modulus

printf("\nMOD A,B\n");
printf("|% .2f|\n",vecMod(A)); // 2.24
printf("|% .2f|\n",vecMod(B)); // 3.16

return 0;
}

Type

vector

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typedef struct Vector{
double x;
double y;
double z;
double mag;
}vector;

The vector type contains components in three dimensions and the overall magnitude. All these data are in double type. Each time an operation is performed to a vector, the magnitude would update automatically.

You may get a component directly:

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vector V = vecSet(1.1, 2.2, 3.3);
printf("%f", V.x); // This prints out the x component of vector V

Functions

Arithmetic

Addition

vecAdd(A, B) returns the sum: A + B.

Subtraction

vecSub(A, B) returns the difference: A - B.

Negative

vecNeg(V) returns the negative: - V.

Modulus

vecMod(V) returns the modulus: | V |.

Unit Vector

vecUnit(V) returns the unit vector: ^ V.

Scalar Product

vecScl(V, s) returns the vector s * V.

Dot Product

vecDot(A, B) returns the dot product: A · B.

Cross Product

vecCrx(A, B) returns the Cross product: A × B.

Utilities

Initialization

There’re two ways to initialize a vector:

  1. vecSet(x, y, z) returns a vector specify the coordinates (x,y,z).
  2. vecInit() returns a vector with coordinates all of 0.0. However, you should use vecSet(0.0, 0.0, 0.0) instead for better readability.

Pretty Print

  1. vecPrint(V) prints the vector in the form of <x, y, z> | modulus |, 2 decimal places by default
  2. vecnPrint(V, p) using the specified precision p. If p is 0, print in exponential form.