/* == veclib3d.c == */

void vl_idmat3(
double mtx[3][3]);

/* Scale a 3d vector */

void vl_scale3(
double fact,
double *v1,
double *v2);

void vl_reverse3(
double *v1,
double *v2);

void vl_copy3(
double *vin,
double *vout);

/* Find the inner product of two input vectors */

double vl_dot3(
double *v1,       /* Left input vector  */
double *v2);

/* Return length of a 3d vector */

double vl_length3(
double *v1);

/* Compute the difference of two vectors */
/* v3 = v2 - v1                          */

void vl_diff3(
double *v1,        /*  --  input vector  */
double *v2,        /*  --  input vector */
double *v3);

/* Compute the sum of two vectors */

void vl_sum3(
double *v1,        /* Left input vector  */
double *v2,        /* Right input vector */
double *v3);

/* Construct a unit length vector in the required direction */

void vl_unitvec3(
double *v1,        /* Input vector  */
double *v2);

/* Compute the outer product of two input vectors */

void vl_cross3(
double *v1,         /* Left input vector  */
double *v2,         /* Right input vector */
double *v3);

/* 3 x 3 matrix multiplier */

void vl_matmul3(
double x[3][3],       /* Left input matrix  */
double y[3][3],       /* Right input matrix */
double z[3][3]);

 /* n x n matrix transpose  */

void vl_xpose3(
double  x[3][3],       /* Left input matrix  */
double  z[3][3]);

/* Print the contents of a transform matrix */

void vl_matprn3(
char *label,
double mat[3][3]);

/* Print the contents of a vector */

void vl_vecprn3(
char *label,
double vec[3]);

/* Create a matrix to rotate a vector around the y axis */

void vl_xzrot3(
double matrix[3][3],     /* Matrix to be filled in    */
double theta);

/* Create a matrix to rotate a vector around the x axis */

void vl_yzrot3(
double matrix[3][3],    /* Matrix to be filled in    */
double theta);

/* Create a matrix to rotate a vector around the z axis */

void vl_xyrot3(
double matrix[3][3],    /* Matrix to be filled in    */
double theta);

/* Perform a linear transform in four dimensional space */
/* By applying a 3 x 3 matrix to a 3 x 1 column vector  */

void vl_xform3d(
double y[3][3],       /* Xform matrix  */
double x[3],          /* Input vector  */
double z[3]);

/* Perform a linear transform in four dimensional space */
/* By applying a 3 x 3 matrix to a 3 x 1 column vector  */

void vl_xfnadd3(
double y[3][3],       /* Xform matrix  */
double x[3],          /* Input vector  */
double z[3]);

void vl_reflect3(
double *in,
double *norm,
double *out);