i have a float data[9];

i need to normalize this

but i tryed to do

data = normalize(data)

which it did not like , because its an array ,

how would i code this please

Ehm, language?

If data[9] is simply a 9 dimensional vector you can do it manually:

float z = 0;

for(int i = 0; i < 9; i++)
    z += pow(data, 2);

z = sqrt(z);

for(int i = 0; i < 9; i++)
    data /= z; //Or use a temporary vector if "data" is in a constant buffer

If data[9] is a 3x3 matrix divide each value by the determinant.

Do you have to normalize it in the shaders? It would be faster do normalize it in the CPU and send to the shaders.