Thread: how to represent velocity vector ?

Hi,

I need to understand the proper way to represent vector in C. Can any one give a hint for it.?
V = ui+vj+wk.

Thanks in advance
shiv

The i, j, and k parts are unit vectors that depict the direction of each component of the vector.

Basically, represent a vector in C using a 1 dimensional array. In your case, an array of 3 elements. It's up to you to maintain how to index the components of the vector.

Originally Posted by MutantJohn

The i, j, and k parts are unit vectors that depict the direction of each component of the vector.

Basically, represent a vector in C using a 1 dimensional array. In your case, an array of 3 elements. It's up to you to maintain how to index the components of the vector.

Thanks for the reply

My case is 3D.. is this correct for 3D vector, V[i][j][k].?

I don't understand the meaning of presenting and "my case is 3d" ?

And try to save i, j and k for your loops. Just a convention. Use x, y and z instead.

Originally Posted by Carnotter

I don't understand the meaning of presenting and "my case is 3d" ?

And try to save i, j and k for your loops. Just a convention. Use x, y and z instead.

Thank you for the reply.

It means velocity is flowing in all three directions... Thank you

Code:

for(x=0;x<10;i++)
{
    for(y=0;y<10;j++)
    {
        for(z=0;z<10;z++)
        {
            printf("%d", v[x][y][z]);
        }
    }
    
}

Is this simple code correct for representing a 3D vector?. If it is correct then I will develop the similar code to compute the velocity..

shiv

You don't need a 3D array.

All vectors are 1 dimensional. Matrices are 2 dimensional.

a i + b j + c k is represented in vector form as (a, b, c) so all you need is :

Code:

#include <stdio.h>


enum { x = 0, y = 1, z = 2 };


int main(void)
{
    float v[3] = { 0 };


    v[x] = 1.23;
    v[y] = 2.56;
    v[z] = 34.0;


    printf("v = { %f, %f, %f }\n", v[x], v[y], v[z]);


    return 0;
}

All your doing in this case is using a 1D array to store your vector and we use an enumeration for intuitive indexing of the array.

Originally Posted by MutantJohn

You don't need a 3D array.

All vectors are 1 dimensional. Matrices are 2 dimensional.

a i + b j + c k is represented in vector form as (a, b, c) so all you need is :

Code:

#include <stdio.h>


enum { x = 0, y = 1, z = 2 };


int main(void)
{
    float v[3] = { 0 };


    v[x] = 1.23;
    v[y] = 2.56;
    v[z] = 34.0;


    printf("v = { %f, %f, %f }\n", v[x], v[y], v[z]);


    return 0;
}

All your doing in this case is using a 1D array to store your vector and we use an enumeration for intuitive indexing of the array.

Thank you so much. you have solved my problem.. Now I can develop my program easily.