1STINIT(3NCARG)                   NCAR GRAPHICS                  STINIT(3NCARG)
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NAME

6       STINIT - Performs initialization tasks required before STREAM may be
7       called to create a streamline field flow plot.  Information about the
8       input data arrays is copied into internal common block variables and
9       the coordinate system mappings and boundaries are established.
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SYNOPSIS

12       CALL STINIT (U,LU,V,LV,P,LP,M,N,WRK,LW)
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C-BINDING SYNOPSIS

15       #include <ncarg/ncargC.h>
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17       void c_stinit(float *u, int lu, float *v, int lv,
18                     float *p, int lp, int m, int n,
19                     float *wrk, int lw)
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DESCRIPTION

22       U           (REAL 2-dimensional array, dimensioned LU x n: n >= N,
23                   input): By default, assumed to contain the first
24                   dimensional Cartesian components of the vector field.
25                   However, if PLR is non-zero, it is treated as containing
26                   the vector magnitudes.
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28       LU          (INTEGER, input): Actual value of the first dimension of
29                   array U.
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31       V           (REAL 2-dimensional array, dimensioned LV x n: n >= N,
32                   input): By default, assumed to contain the second
33                   dimensional Cartesian components of the vector field.
34                   However, if PLR is non-zero, it is treated as containing
35                   the vector angles.
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37       LV          (INTEGER, input): Actual value of the first dimension of
38                   array V.
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40       P           (REAL, input, DUMMY): This argument is currently ignored
41                   and may be assigned a dummy value.
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43       LP          (INTEGER, input, DUMMY): The first dimension of array P.
44                   Not currently used, this argument should be assigned the
45                   integer value 0.
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47       M           (INTEGER, input): Number of contiguous elements along the
48                   first dimensional axis containing data to be processed in
49                   each of the arrays, U and V.
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51       N           (INTEGER, input): Number of contiguous elements along the
52                   second dimensional axis containing data to be processed in
53                   each of the arrays, U and V.
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55       WRK         (REAL, array dimensioned n: n >= LW, input/output): Work
56                   array used to store normalized values of the U and V vector
57                   components while the streamlines are calculated. It also
58                   holds bit flags indicating whether a grid location is
59                   eligible for starting a streamline or placing a directional
60                   arrowhead.
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62       LW          (INTEGER, input): Assumed size of the array WRK.  Currently
63                   it must greater or equal to 2*M*N.
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C-BINDING DESCRIPTION

66       The C-binding argument descriptions are the same as the FORTRAN
67       argument descriptions, with the following exceptions:
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70       lu          The second dimension of u in the calling program.
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72       lv          The second dimension of v in the calling program.
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74       lp          The second dimension of p in the calling program.
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76       m           Number of contiguous elements along the second dimension
77                   containing data to be processed in each of the arrays, u
78                   and v.
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80       n           Number of contiguous elements along the first dimension
81                   containing data to be processed in each of the arrays, u
82                   and v.
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USAGE

85       Call STINIT before the first invocation of STREAM, and again anytime
86       you modify the contents of the input data arrays. You may precede an
87       STINIT call with any number of calls to the parameter setting routines,
88       STSETR and STSETI. Although it is possible to call STSETI or STSETR
89       between calls to STINIT and STREAM, changing the setting of many of
90       Streamline's parameters at this point will result in incorrect
91       behavior. When in doubt, set parameters before the STINIT call; see the
92       streamlines_params man page for more information.
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94       Set up the two vector component arrays prior to calling STINIT.  To
95       permit multiple purpose use of the array space, the STINIT argument
96       list includes both the actual size and an assumed size for the first
97       dimension of each input array. Due to FORTRAN array ordering
98       conventions, only the assumed size needs to be specified for the second
99       dimension.  (Note: when using the C bindings, mentally exchange all
100       references to first and second dimensions in this discussion.) The
101       arguments LU and LV contain the actual size of the first dimensions of
102       U and V, respectively. Since the grid locations for each of the data
103       arrays are assumed to coincide, a single argument, M, represents the
104       assumed size of the first dimension for both arrays. Similarly, the
105       argument, N, is the assumed size of the second dimension. The only
106       requirement for the actual second dimension size is that it be greater
107       than or equal to N for each array.
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109       The P and LP arguments are intended for future enhancement of the
110       Streamlines utility. They are not currently used or examined in any
111       way. For maximum assurance of compatibility with future changes to the
112       code, give the LP argument the INTEGER value 0.
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114       WRK is an array used to store normalized values of the U and V vector
115       components while the streamlines are calculated. It also holds bit
116       flags indicating whether a grid location is eligible for starting a
117       streamline or placing a directional arrowhead. Its assumed size is
118       specified by the argument LW. LW must have a value greater or equal to
119       2*M*N.
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EXAMPLES

122       Use the ncargex command to see the following relevant examples: ffex00,
123       ffex01, ffex03, ffex04, fstream, stex01, stex02, stex03.
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ACCESS

126       To use STINIT or c_stinit, load the NCAR Graphics libraries ncarg,
127       ncarg_gks, and ncarg_c, preferably in that order.
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MESSAGES

130       See the streamlines man page for a description of all Streamlines error
131       messages and/or informational messages.
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SEE ALSO

134       Online: stgetc, stgeti, stgetr, stream, streamlines,
135       streamlines_params, strset, stsetc, stseti, stsetr, stuixy, stumsl,
136       stumta, stumxy, ncarg_cbind.
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138       Hardcopy: NCAR Graphics Fundamentals, UNIX Version
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141       Copyright (C) 1987-2009
142       University Corporation for Atmospheric Research
143       The use of this Software is governed by a License Agreement.
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147UNIX                              April 1993                    STINIT(3NCARG)
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