VVINIT(3NCARG) | NCAR GRAPHICS | VVINIT(3NCARG) |
VVINIT - Performs initialization tasks required before VVECTR may be called to plot a vector field, including copying array size information into internal common block variables, establishing coordinate system mappings and boundaries, determining the maximum and minimum vector magnitudes and scalar array values, and, if required, setting up the color threshold value array.
CALL VVINIT (U,LU,V,LV,P,LP,M,N,WRK,LW)
#include <ncarg/ncargC.h>
void c_vvinit(float *u, int lu, float *v, int lv,
float *p, int lp, int m, int n,
float *wrk, int lw)
The C-binding argument descriptions are the same as the FORTRAN argument descriptions with the following exceptions:
Call VVINIT before the first invocation of VVECTR and again anytime you modify the contents of the input data arrays. You may precede a VVINIT call with any number of calls to the Vectors parameter setting routines (VVSETC, VVSETI, or VVSETR). After the VVINIT call, you may still change certain parameters before calling VVECTR. (Consult the vectors_params man page for further information on this point.)
Set up the two vector component arrays prior to calling VVINIT. To permit multiple purpose use of the array space, the VVINIT argument list includes both the actual size and an assumed size for the first dimension of each input array. Due to FORTRAN array ordering conventions, only the assumed size needs to be specified for the second dimension. (Note: when using the C bindings, mentally exchange all references to first and second dimensions in this discussion.) The arguments LU, LV, and LP contain the actual size of the first dimensions of arrays U, V, and P respectively. Since the grid locations for each of the data arrays are assumed to coincide, a single argument, M, represents the assumed size of the first dimension for all the arrays. Similarly, the argument, N, is the assumed size of the second dimension. The only requirement for the actual second dimension size is that it be greater than or equal to N for each array.
The array specified by the WRK argument and its associated size specifier, LW, are used only when the parameter VMD (Vector Minimum Distance) is given a value greater than 0.0. In this case, Vectors uses the array to keep track of the location of each vector in NDC space so that the distances between vectors can be compared. Based on these comparisons, Vectors eliminates some vectors such that the remaining vectors are separated by at least the specified distance. If VMD is less than or equal to 0.0, you may assign an arbitrary dummy value to WRK, but you should set LW to the integer value 0.
C-Binding usage is the same as FORTRAN usage discussed above if the references to "first dimension" and "second dimension" are exchanged.
Use the ncargex command to see the following relevant examples: bnchmk, fcover, ffex00, ffex01, ffex02, ffex05, stex02, stex03, vvex01, vvex02.
To use VVINIT or c_vvinit, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.
See the vectors man page for a description of all Vectors error messages and/or informational messages.
Online: vectors, vectors_params, vvectr, vvgetc, vvgeti, vvgetr, vvrset, vvsetc, vvseti, vvsetr, vvudmv, vvumxy, ncarg_cbind.
Hardcopy: NCAR Graphics Fundamentals, UNIX Version
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University Corporation for Atmospheric Research
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April 1993 | UNIX |