a=1/Sqr(b) is an high time consuming operation.
This function is intensively used in vector operation, such normalization:
eg: D=sqr(dx*dx+dy*dy) , dx=dx/d , dy=dy/d
In C and other languages there's a technique to do this opertation in a fast way called
fast inverse square root
Look here and here.
Don't know if it could worth to translate these codes to VB6 and if the new (VB6) InvSqrt function could be faster than
1/Sqr(b).
Could someone Help about this?
(Sorry for my english)
This function is intensively used in vector operation, such normalization:
eg: D=sqr(dx*dx+dy*dy) , dx=dx/d , dy=dy/d
In C and other languages there's a technique to do this opertation in a fast way called
fast inverse square root
Look here and here.
Code:
float InvSqrt(float x)
{
float xhalf = 0.5f*x;
int i = *(int*)&x; // get bits for floating value
i = 0x5f375a86- (i>>1); // gives initial guess y0
x = *(float*)&i; // convert bits back to float
x = x*(1.5f-xhalf*x*x); // Newton step, repeating increases accuracy
return x;
}Code:
public static float invSqrt(float x) {
float xhalf = 0.5f*x;
int i = Float.floatToIntBits(x);
i = 0x5f3759df - (i>>1);
x = Float.intBitsToFloat(i);
x = x*(1.5f - xhalf*x*x);
return x;
}1/Sqr(b).
Could someone Help about this?
(Sorry for my english)