genVectorLength
in genMath.lib
Vector Functions Function List by Category Alphabetical Function List
int genVectorLength(
float *Vector, // pointer to array holding
vector A
int dimen,
// dimension of vector
float *Length) // pointer to
store result
This
function computes the length of a vector of dimension n. The function
'assumes'
that one end of the vector is at the origin. If you need to compute the
length of a
more general vector, pass the coordinate differences to the function (such as x1
- x2,
y1-y2):
Length = sqrt{ sum{ a[i]^2 } }
The explicit routines VectorLength2d and VectorLength3d
are faster due to code
optimizations in explicit algorithms.
The
return code is errno, defined in the C standard library (math.h). This is
an integer value
for math errors.
Sample Application:
/////////// splgnLen.c for genVectorLength Library Function ////////// // // // // For this sample, a 3-d vector is used. The vector is // // stored in array a, and the length is returned into // // c. // // // ////////////////////////////////////////////////////////////////////// //////////////////////////// INCLUDES //////////////////////////////// #include "stdio.h" #include "genMath.h" ////////////////////////////// MAIN ////////////////////////////////// void main() { //local declarations //integers int retcode; // return code for call to genVectorLength //floats float a[3]; // vector float c; // Length of vector //character strings char ch; // input string to exit //intialize the A and B vectors a[0] = (float)1.234; a[1] = (float)-.678; a[2] = (float)10.3; //compute the length retcode = genVectorLength(a,3,&c); //display the result printf("%s%f%s", "Vector Length = ", c,"\n\n"); //display closing message and wait for <enter> before exiting printf("Press <Enter> to end"); scanf("%c", &ch); } // End Main /////////////////////////////// End splgnLen.c ///////////////////////
The reader may compute the length of A and compare to the output of the sample program.
Output from the test program splgnLen.c:
Vector Length = 10.395789