Detailed description of the procedures
NATGRIDS - primary gridding function
NATGRIDS is the Fortran single-precision subroutine that
does an interpolation from 2D random data to an output
grid. NATGRIDS is called after all of the desired values for
control parameters have
been set using the subroutines
NNSETI,
NNSETR,
NNSETC.
--------------------------------------------------------------
Argument | Type | Mode | Dimension
--------------------------------------------------------------
CALL NATGRIDS (NPNTS, | Integer | Input |
X, | Real | Input | NPNTS
Y, | Real | Input | NPNTS
Z, | Real | Input | NPNTS
NUMXOUT, | Integer | Input |
NUMYOUT, | Integer | Input |
XI, | Real | Input | NUMXOUT
YI, | Real | Input | NUMYOUT
ZI, | Real | Output | NUMXOUT x NUMYOUT
IER) | Integer | Output |
--------------------------------------------------------------
- NPNTS
- The number of input data points. (NPNTS > 3)
- X
- An array containing the X coordinates of the input data points.
- Y
- An array containing the Y coordinates of the input data points.
- Z
- An array containing the functional values
of the input data points. That is, Z(L) is the value of the
input function at coordinate (X(L),Y(L)), for L=1,NPNTS.
- NUMXOUT
- The number of X values in the output grid.
- NUMYOUT
- The number of Y values in the output grid.
- XI
- An array of dimension NUMXOUT containing the X coordinates
of the output data grid. The values in XI must be increasing,
but need not be equally spaced.
- YI
- An array of dimension NUMYOUT containing the Y coordinates
of the output data grid. The values in YI must be increasing,
but need not be equally spaced.
- ZI
- A two-dimensional array of dimension NUMXOUT x NUMYOUT
containing the interpolated functional values. ZI(I,J) is
the interpolated
value at grid point (XI(I),YI(J)).
- IER
- An error return value. If IER is returned as 0, then no
errors were detected. If IER is non-zero, then refer to the
error list in
the error table for details.
NNSETI - set INTEGER parameter values
NNSETI is used to set values for any of the
control parameters
that take integer values. The values set by NNSETI remain in effect
until changed by subsequent calls to NNSETI.
-----------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------
CALL NNSETI (PNAM, | Character | Input |
IVAL) | Integer | Input |
-----------------------------------------------------
- PNAM
- The name of the
control parameter
to be set.
- IVAL
- The value to be assigned to the parameter.
NNGETI - retrieve values for INTEGER parameters
NNGETI is a called to obtain current values for any of the INTEGER
valued
control parameters.
-----------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------
CALL NNGETI (PNAM, | Character | Input |
IVAL) | Integer | Output |
-----------------------------------------------------
- PNAM
- The name of the control parameter whose value is to be retrieved.
- IVAL
- The current value assigned to the control parameter.
NNSETR - set REAL parameter values
NNSETR is used to set values for any of the
control parameters
that take REAL values. The values set by NNSETR remain in effect
until changed by subsequent calls to NNSETR.
-----------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------
CALL NNSETR (PNAM, | Character | Input |
RVAL) | Real | Input |
-----------------------------------------------------
- PNAM
- The name of the control parameter to be set.
- RVAL
- The value to be assigned to the parameter.
NNGETR - retrieve values for REAL parameters
NNGETR is a called to obtain current values for any of the REAL valued
control parameters.
-----------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------
CALL NNGETR (PNAM, | Character | Input |
RVAL) | Real | Output |
-----------------------------------------------------
- PNAM
- The name of the control parameter whose value is to be retrieved.
- RVAL
- The current value assigned to the control parameter.
NNSETC - set CHARACTER valued parameters
-----------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------
CALL NNSETC (PNAM, | Character | Input |
CVAL) | Character | Input |
-----------------------------------------------------
NNSETC is used to set values for any of the
control parameters
that take CHARACTER values. The values set by NNSETC remain in effect
until changed by subsequent calls to NNSETC.
- PNAM
- The name of the control parameter to be set.
- CVAL
- The value to be assigned to the parameter.
NNGETC - retrieve values for CHARACTER parameters
NNGETC is a called to obtain current values for any of the CHARACTER valued
control parameters.
-----------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------
CALL NNGETC (PNAM, | Character | Input |
CVAL) | Character | Output |
-----------------------------------------------------
- PNAM
- The name of the
control parameter
whose value is to be retrieved.
- CVAL
- The current value assigned to the control parameter.
Be sure to provide enough space in the character variable to
receive the value.
NNGETASPECTS is called to retrieve an
aspect, in single precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
-----------------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------------
CALL NNGETASPECTS (I, | Integer | Input |
J, | Integer | Input |
ASPECT, | Real | Output |
IER) | Integer | Output |
-----------------------------------------------------------
- I
- A subscript indexing the first dimensioned variable in the
output grid of the most recent call to NATGRIDS.
- J
- A subscript indexing the second dimensioned variable in
the output grid in the most recent call to
NATGRIDS.
- ASPECT
- The aspect at the grid point Z(I,J), where Z is the output
grid in the most recent call to NATGRIDS.
- IER
- An error return value. If IER is returned as 0, then no
errors were detected. If IER is non-zero, then refer to the
error list in the
error table for details.
NNGETSLOPES is called to retrieve a
slope, in single precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
----------------------------------------------------------
Argument | Type | Mode | Dimension
----------------------------------------------------------
CALL NNGETSLOPES (I, | Integer | Input |
J, | Integer | Input |
SLOPE, | Real | Output |
IER) | Integer | Output |
----------------------------------------------------------
- I
- A subscript indexing the first dimensioned variable in the
output grid of the most recent call to NATGRIDS.
- J
- A subscript indexing the second dimensioned variable in the
output grid in the most recent call to NATGRIDS.
- SLOPE
- The slope at the grid point Z(I,J), where Z is the output grid
in the most recent call to NATGRIDS.
- IER
- An error return value. If IER is returned as 0, then no
errors were detected. If IER is non-zero, then refer to the
error list in the
error table for details.
NNPNTINITS - initiate single-point mode
This subroutine calculates all natural neighbor relationships in an
input data array and sets some internal parameters so that
NNPNTS
can be called to interpolate at individual points.
----------------------------------------------------------
Argument | Type | Mode | Dimension
----------------------------------------------------------
CALL NNPNTINITS (NPNTS, | Integer | Input |
X, | Real | Input | NPNTS
Y, | Real | Input | NPNTS
Z) | Real | Input | NPNTS
----------------------------------------------------------
- NPNTS
- The number of input data points. (NPNTS > 3)
- X
- An array of dimension NPNTS containing the X coordinates
of the input data points.
- Y
- An array of dimension NPNTS containing the Y coordinates
of the input data points.
- Z
- An array of dimension NPNTS containing the functional
values of the input data points. That is, Z(L) is the
value of the input function at
coordinate (X(L),Y(L)), for L=1,NPNTS.
NNPNTS - interpolate at a single point
This subroutine is called to interpolate at a specified point.
Before calling this subroutine,
NNPNTINITS must be called.
-------------------------------------------------------
Argument | Type | Mode | Dimension
-------------------------------------------------------
CALL NNPNTS (X, | Real | Input |
Y, | Real | Input |
Z) | Real | Output |
-------------------------------------------------------
- X
- The X coordinate of the point where interpolation is desired.
- Y
- The Y coordinate of the point where interpolation is desired.
- Z
- The interpolated functional value at the point (X,Y).
NNPNTEND - terminate single-point mode
This subroutine is called to terminate interpolation at single points.
It is called after having made previous calls to
NNPNTINITS and
NNPNTS.
--------------------------------------------
Argument | Type | Mode | Dimension
--------------------------------------------
CALL NNPNTEND () | N/A | N/A | N/A
--------------------------------------------
NATGRIDD - primary gridding function
NATGRIDD is the Fortran double-precision subroutine that
does an interpolation from 2D random data to an output
grid. NATGRIDD is called after all of the desired values for
control parameters have
been set using the subroutines
NNSETI,
NNSETRD,
NNSETC.
------------------------------------------------------------------------
Argument | Type | Mode | Dimension
------------------------------------------------------------------------
CALL NATGRIDD (NPNTS, | Integer | Input |
X, | Double precision | Input | NPNTS
Y, | Double precision | Input | NPNTS
Z, | Double precision | Input | NPNTS
NUMXOUT, | Integer | Input |
NUMYOUT, | Integer | Input |
XI, | Double precision | Input | NUMXOUT
YI, | Double precision | Input | NUMYOUT
ZI, | Double precision | Output | NUMXOUT x NUMYOUT
IER) | Integer | Output |
------------------------------------------------------------------------
- NPNTS
- The number of input data points. (NPNTS > 3)
- X
- An array of dimension NPNTS containing the X coordinates of the
input data points.
- Y
- An array of dimension NPNTS containing the Y coordinates of the
input data points.
- Z
- An array of dimension NPNTS containing the functional values of the
input data points. That is, Z(L) is the value of the input function at
coordinate (X(L),Y(L)), for L=1,NPNTS.
- NUMXOUT
- The number of X values in the output grid.
- NUMYOUT
- The number of Y values in the output grid.
- XI
- An array of dimension NUMXOUT containing the X coordinates of the
output data grid. The values in XI must be increasing, but need not be
equally spaced.
- YI
- An array of dimension NUMYOUT containing the Y coordinates of the
output data grid. The values in YI must be increasing, but need not be
equally spaced.
- ZI
- A two-dimensional array of dimension NUMXOUT x NUMYOUT
containing the interpolated functional values. ZI(I,J) is the
interpolated value at grid point (XI(I),YI(J)).
- IER
- An error return value. If IER is returned as 0, then no errors were
detected. If IER is non-zero, then refer to the error list in
the error table
for details.
NNSETRD - set DOUBLE PRECISION parameter values
NNSETRD is used to set values for any of the
control parameters
that take DOUBLE PRECISION values. The values set by NNSETRD remain in effect
until changed by subsequent calls to NNSETRD.
-------------------------------------------------------------
Argument | Type | Mode | Dimension
-------------------------------------------------------------
CALL NNSETRD (PNAM, | Character | Input |
RVAL) | Double precision | Input |
-------------------------------------------------------------
- PNAM
- The name of the
control parameter
to be set.
- RVAL
- The value to be assigned to the parameter.
NNGETRD - retrieve values for DOUBLE PRECISION
parameters
NNGETRD is a called to obtain current values for any of the
DOUBLE PRECISION valued
control parameters.
-------------------------------------------------------------
Argument | Type | Mode | Dimension
-------------------------------------------------------------
CALL NNGETRD (PNAM, | Character | Input |
RVAL) | Double precision | Output |
-------------------------------------------------------------
- PNAM
- The name of the
control parameter
whose value is to be retrieved.
- RVAL
- The current value assigned to the control parameter.
NNGETASPECTD is called to retrieve an
aspect, in double precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
------------------------------------------------------------------
Argument | Type | Mode | Dimension
------------------------------------------------------------------
CALL NNGETASPECTD (I, | Integer | Input |
J, | Integer | Input |
ASPECT, | Double precision | Output |
IER) | Integer | Output |
------------------------------------------------------------------
- I
- A subscript indexing the first dimensioned variable in the output grid
of the most recent call to NATGRIDD.
- J
- A subscript indexing the second dimensioned variable in the output
grid in the most recent call to NATGRIDD.
- ASPECT
- The aspect at the grid point Z(I,J), where Z is the output grid in the
most recent call to NATGRIDD.
- IER
- An error return value. If IER is returned as 0, then no errors were
detected. If IER is non-zero, then refer to the error list in
the error table
for details.
NNGETSLOPED is called to retrieve a
slope, in double precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
-----------------------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------------------
CALL NNGETSLOPED (I, | Integer | Input |
J, | Integer | Input |
SLOPE, | Double precision | Output |
IER) | Integer | Output |
-----------------------------------------------------------------
- I
- A subscript indexing the first dimensioned variable in the output grid
of the most recent call to NATGRIDD.
- J
- A subscript indexing the second dimensioned variable in the output
grid in the most recent call to NATGRIDD.
- SLOPE
- The slope at the
grid point Z(I,J), where Z is the output grid in the
most recent call to NATGRIDD.
- IER
- An error return value. If IER is returned as 0, then no errors were
detected. If IER is non-zero, then refer to the error list in
the error table
for details.
NNPNTINITD - initiate single-point mode
This subroutine calculates all natural neighbor relationships in an input data
array and sets some internal parameters so that
NNPNTD can be called to
interpolate at individual points.
-----------------------------------------------------------------
Argument | Type | Mode | Dimension
-----------------------------------------------------------------
CALL NNPNTINITD (NPNTS, | Integer | Input |
X, | Double precision | Input | NPNTS
Y, | Double precision | Input | NPNTS
Z) | Double precision | Input | NPNTS
-----------------------------------------------------------------
- NPNTS
- The number of input data points. (NPNTS > 3)
- X
- An array of dimension NPNTS containing the X coordinates of the
input data points.
- Y
- An array of dimension NPNTS containing the Y coordinates of the
input data points.
- Z
- An array of dimension NPNTS containing the functional values of the
input data points. That is, Z(L) is the value of the input function at
coordinate (X(L),Y(L)), for L=1,NPNTS.
NNPNTD - interpolate at a single point
This subroutine is called to interpolate at a specified point.
Before calling this subroutine,
NNPNTINITD must be called.
--------------------------------------------------------
Argument | Type | Mode | Dimension
--------------------------------------------------------
CALL NNPNTD (X, | Double precision | Input |
Y, | Double precision | Input |
Z) | Double precision | Output |
--------------------------------------------------------
- X
- The X coordinate of the point where interpolation is desired.
- Y
- The Y coordinate of the point where interpolation is desired.
- Z
- The interpolated functional value at the point (X,Y).
NNPNTENDD - terminate single-point mode
This subroutine is called to terminate interpolation at single points.
It is called after having made previous calls to
NNPNTINITD and
NNPNTD.
---------------------------------------------
Argument | Type | Mode | Dimension
---------------------------------------------
CALL NNPNTENDD () | N/A | N/A | N/A
---------------------------------------------
c_natgrids - Primary gridding function
c_natgrids is the C single-precision function that
does an interpolation from 2D random data to an output
grid. c_natgrids is called after all of the desired values for
control parameters have
been set using the procedures
c_nnseti,
c_nnsetr,
c_nnsetc.
Function prototype:
float *c_natgrids(int, float [], float [], float [],
int, int, float [], float [], int *);
Return value:
c_natgrids returns a pointer to a linear array of data
that is the interpolated grid stored in row-major order.
That is, if out is declared as
float *out;
and we set:
out = c_natgrids(npnts, x, y, z, numxout, numyout, xo, yo, &ier);
then out[i*numyout+j] is the interpolated function value at
coordinate point (xo[i],yo[j]) for 0 <= i < numxout and 0 <= j < numyout.
The space for
out is allocated internal to c_natgrids and is
numxout*numyout floats in size.
Argument description:
-------------------------------------------------
Argument | Type | Size
-------------------------------------------------
float *c_natgrids (npnts, | int |
x, | float [] | npnts
y, | float [] | npnts
z, | float [] | npnts
numxout, | int |
numyout, | int |
xi, | float [] | numxout
yi, | float [] | numyout
ier | int * |
);
-------------------------------------------------
- npnts
- The number of input data points. (npnts > 3)
- x
- An array of size npnts containing the X coordinates of the input data
points.
- y
- An array of size npnts containing the Y coordinates of the input data
points.
- z
- An array of size npnts containing the functional values of the input
data points. That is, z[n] is the value of the input function at
coordinate (x[n],y[n]), for 0 <= n < npnts.
- numxout
- The number of X values in the output grid.
- numyout
- The number of Y values in the output grid.
- xi
- An array of size numxout containing the X coordinates of the output
data grid. The values in xi must be increasing, but need not be equally
spaced.
- yi
- An array of size numyout containing the Y coordinates of the output
data grid. The values in yi must be increasing, but need not be equally
spaced.
- ier
- An error return value. If *ier is returned as 0, then no errors were
detected. If *ier is non-zero, then refer to the error list in
the error table
for details.
c_nnseti - Set int valued parameters
c_nnseti is used to set values for any of the
control parameters
that take int values. The values set by c_nnseti remain in effect
until changed by subsequent calls to c_nnseti.
Function prototype:
void c_nnseti(char *, int);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nnseti (pnam, | char * |
ival); | int |
-------------------------------------------
- pnam
- The name of the
control parameter
to be assigned an int value.
- ival
- The value to be assigned to the control parameter whose name is
pointed to by pnam.
c_nngeti is a called to obtain current values for any of the int valued
control parameters.
Function prototype:
void c_nngeti(char *, int);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nngeti (pnam, | char * |
ival); | int * |
-------------------------------------------
- pnam
- The name of the
control parameter
whose value is to be retrieved.
- ival
- *ival will be the value currently assigned to the control parameter
whose name is pointed to by pnam.
c_nnsetr - Set float valued parameters
c_nnsetr is used to set values for any of the
control parameters
that take float values. The values set by c_nnsetr remain in effect
until changed by subsequent calls to c_nnsetr.
Function prototype:
void c_nnsetr(char *, float);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nnsetr (pnam, | char * |
fval); | float |
-------------------------------------------
- pnam
- The name of the
control parameter
to be assigned a float value.
- fval
- The value to be assigned to the control parameter whose name is
pointed to by pnam.
c_nngetr - Retrieve a float valued parameter
c_nngetr is a called to obtain current values for any of the float valued
control parameters.
Function prototype:
void c_nngetr(char *, float *);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nngetr (pnam, | char * |
fval); | float * |
-------------------------------------------
- pnam
- The name of the
control parameter
whose value is to be retrieved.
- fval
- *fval will be the value currently assigned to the control parameter
whose name is pointed to by pnam.
c_nnsetc - Set char valued parameters
c_nnsetc is used to set values for any of the
control parameters
that take string values. The values set by c_nnsetc remain in effect
until changed by subsequent calls to c_nnsetc.
Function prototype:
void c_nnsetc(char *, char *);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nnsetc (pnam, | char * |
cval); | char * |
-------------------------------------------
- pnam
- The name of the
control parameter
to be assigned a char value.
- cval
- The value to be assigned to the control parameter whose name is
pointed to by pnam.
c_nngetc is a called to obtain current values for any of the string valued
control parameters.
Function prototype:
void c_nngetc(char *, char *);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nngetc (pnam, | char * |
cval); | char * |
-------------------------------------------
- pnam
- The name of the
control parameter
whose value is to be retrieved.
- cval
- cval will point to a string containing the returned value.
The user is required to reserve enough space to store the string.
c_nngetaspects is called to retrieve an
aspect, in single precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
Function prototype:
void c_nngetaspects(int, int, float *, int *);
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nngetaspects (row, | int |
column, | int |
aspect, | float * |
ier); | int * |
-----------------------------------------------
- row
- A subscript indexing the first dimensioned variable in the
2D grid array returned from the most recent call to
c_natgrids.
- column
- A subscript indexing the second dimensioned variable in the
2D grid array returned from the most recent call to
c_natgrids.
- aspect
- *aspect is the aspect
at the grid point z[i,j], where z is the output grid
in the most recent call to
c_natgrids.
- ier
- *ier is an error return value. If *ier is 0, then no errors
were detected. If *ier is non-zero, then refer to the error
list in
the error table
for details.
c_nngetslopes is called to retrieve a
slope, in single precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
Function prototype:
void c_nngetslopes(int, int, float *, int *);
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nngetslopes (row, | int |
column, | int |
slope, | float * |
ier); | int * |
-----------------------------------------------
- row
- A subscript indexing the first dimensioned variable in the
2D grid array returned from the most recent call to
c_natgrids.
- column
- A subscript indexing the second dimensioned variable in the
2D grid array returned from the most recent call to
c_natgrids.
- slope
- *slope is the slope at the
grid point z[i,j], where z is the output grid in
the most recent call to c_natgrids.
- ier
- *ier is an error return value. If *ier is 0, then
no errors were detected. If *ier is non-zero, then refer to the
error list in
the error table for details.
c_nnpntinits - Enter single-point mode
This function calculates all natural neighbor relationships in an
input data array and sets some internal parameters so that
c_nnpnts
can be called to interpolate at individual points.
Function prototype:
void c_nnpntinits(int, float [], float [], float []);
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nnpntinits (npnts, | int |
x, | float [] | npnts
y, | float [] | npnts
z); | float [] | npnts
-----------------------------------------------
- npnts
- The number of input data points. (npnts > 3)
- x
- An array of size npnts containing the X coordinates of the input data
points.
- y
- An array of size npnts containing the Y coordinates of the input data
points.
- z
- An array of size npnts containing the functional values of the input
data points. That is, z[n] is the value of the input function at
coordinate (x[n],y[n]), for 0 <= n < npnts.
c_nnpnts - Interpolate at a single point
This function is called to interpolate at a specified point.
Before calling this function,
c_nnpntinits must be called.
Function prototype:
void c_nnpnts(float, float, float *);
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nnpnts (x, | float |
y, | float |
z); | float * |
-----------------------------------------------
- x
- The X coordinate of the point where interpolation is desired.
- y
- The Y coordinate of the point where interpolation is desired.
- z
- *z is the interpolated functional value at the point (X,Y).
c_nnpntend - Exit single-point mode
This function is called to terminate interpolation at single points.
It is called after having made previous calls to
c_nnpntinits and
c_nnpnts.
Function prototype:
void c_nnpntend();
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nnpntend (); | N/A | N/A
-----------------------------------------------
c_natgridd - Primary gridding function
c_natgridd is the C double-precision function that
does an interpolation from 2D random data to an output
grid. c_natgrids is called after all of the desired values for
control parameters have
been set using the function
c_nnseti,
c_nnsetrd,
c_nnsetc.
Function prototype:
double *c_natgridd(int, double [], double [], double [],
int, int, double [], double [], int *);
Return value:
c_natgridd returns a pointer to a linear array of data
that is the interpolated grid stored in row-major order.
That is, if out is declared as
double *out;
and we set:
out = c_natgridd(numin, x, y, z, numxout, numyout, xo, yo, &ier);
then out[i*numyout+j] is the interpolated function value at
coordinate point (xo[i],yo[j]) for 0 <= i < numxout and 0 <= j < numyout.
The space for
out is allocated internal to c_natgridd and is
numxout*numyout double-precision values in size.
Argument description:
-------------------------------------------------
Argument | Type | Size
-------------------------------------------------
double *c_natgridd (npnts, | int |
x, | double [] | npnts
y, | double [] | npnts
z, | double [] | npnts
numxout, | int |
numyout, | int |
xi, | double [] | numxout
yi, | double [] | numyout
ier | int * |
); | |
-------------------------------------------------
- npnts
- The number of input data points. (npnts > 3)
- x
- An array of size npnts containing the X coordinates of the input data
points.
- y
- An array of size npnts containing the Y coordinates of the input data
points.
- z
- An array of size npnts containing the functional values of the input
data points. That is, z[n] is the value of the input function at
coordinate (x[n],y[n]), for 0 <= n < npnts.
- numxout
- The number of X values in the output grid.
- numyout
- The number of Y values in the output grid.
- xi
- An array of size numxout containing the X coordinates of the output
data grid. The values in xi must be increasing, but need not be equally
spaced.
- yi
- An array of size numyout containing the Y coordinates of the output
data grid. The values in yi must be increasing, but need not be equally
spaced.
- ier
- An error return value. If *ier is returned as 0, then no errors were
detected. If *ier is non-zero, then refer to the error list in
the error table
for details.
c_nnsetrd - Set double-precision parameter
values
c_nnsetrd is used to set values for any of the
control parameters
that take double-precision values. The values set by c_nnsetrd remain in
effect until changed by subsequent calls to c_nnsetrd.
Function prototype:
void c_nnsetrd(char *, double);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nnsetrd (pnam, | char * |
dval); | double |
-------------------------------------------
- pnam
- The name of the
control parameter
to be assigned a float value.
- dval
- The value to be assigned to the control parameter whose name is
pointed to by pnam.
c_nngetrd - Retrieve a double-precision
parameter value
c_nngetrd is a called to obtain current values for any of the double-precision
control parameters.
Function prototype:
void c_nngetrd(char *, double *);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nngetrd (pnam, | char * |
dval); | double * |
-------------------------------------------
- pnam
- The name of the
control parameter
whose value is to be retrieved.
- dval
- *dval is the value currently assigned to the control parameter whose
name is pointed to by pnam.
c_nngetaspectd is called to retrieve an
aspect, in double precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
Function prototype:
void c_nngetaspectd(int, int, double *, int *);
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nngetaspectd (row, | int |
column, | int |
aspect, | double * |
ier); | int * |
-----------------------------------------------
- row
- A subscript indexing the first dimensioned variable in the
2D grid array returned from the most recent call to
c_natgrids.
- column
- A subscript indexing the second dimensioned variable in the
2D grid array returned from the most recent call to
c_natgrids.
- aspect
- *aspect is the aspect at
the grid point z[i,j], where z is the output grid
in the most recent call to
c_natgridd.
- ier
- *ier is an error return value. If *ier is 0, then no errors
were detected. If *ier is non-zero, then refer to the error
list in the error table for
details.
c_nngetsloped is called to retrieve a
slope, in double precision, at a specified coordinate value.
For further details, see the module on
computing aspects and slopes.
Function prototype:
void c_nngetsloped(int, int, double *, int *);
Argument description:
----------------------------------------------
Argument | Type | Size
----------------------------------------------
void c_nngetsloped (row, | int |
column, | int |
slope, | double * |
ier); | int * |
----------------------------------------------
- row
- A subscript indexing the first dimensioned variable in the output grid
of the most recent call to c_natgridd.
- column
- A subscript indexing the second dimensioned variable in the output
grid of the most recent call to c_natgridd.
- slope
- *slope is the slope at
the grid point z[i,j], where z is the output grid in
the most recent call to c_natgridd.
- ier
- *ier is an error return value. If *ier is 0, then no errors
were detected. If *ier is non-zero, then refer to the error list in
the error table for details.
c_nnpntinitd - Enter single-point mode
This function calculates all natural neighbor relationships in an
input data array and sets some internal parameters so that
c_nnpntd
can be called to interpolate at individual points.
Function prototype:
void c_nnpntinitd(int, double [], double [], double []);
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nnpntinitd (npnts, | int |
x, | double [] | npnts
y, | double [] | npnts
z); | double [] | npnts
-----------------------------------------------
- npnts
- The number of input data points. (npnts > 3)
- x
- An array of size npnts containing the X coordinates of the input data
points.
- y
- An array of size npnts containing the Y coordinates of the input data
points.
- z
- An array of size npnts containing the functional values of the input
data points. That is, z[n] is the value of the input function at
coordinate (x[n],y[n]), for 0 <= n < npnts.
c_nnpntd - Interpolate at a single point
This function is called to interpolate at a specified point.
Before calling this function,
c_nnpntinitd must be called.
Function prototype:
void c_nnpntd(double, double, double *);
Argument description:
-------------------------------------------
Argument | Type | Size
-------------------------------------------
void c_nnpntd (x, | double |
y, | double |
z); | double * |
-------------------------------------------
- x
- The X coordinate of the point where interpolation is desired.
- y
- The Y coordinate of the point where interpolation is desired.
- z
- *z is the interpolated functional value at the point (X,Y).
c_nnpntendd - Exit single-point mode
This function is called to terminate interpolation at single points.
It is called after having made previous calls to
c_nnpntinitd and
c_nnpntd.
Function prototype:
void c_nnpntendd();
Argument description:
-----------------------------------------------
Argument | Type | Size
-----------------------------------------------
void c_nnpntendd () | N/A | N/A
-----------------------------------------------
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