IBM Visualization Data Explorer Programmer's Reference

DXQueryArrayCommon, DXQueryArrayCommonV

Function

Return a type, category, rank, and shape to which all of the Arrays can be converted.

Syntax

#include <dx/dx.h>

Error DXQueryArrayCommon(Type *type, Category *category, int *rank, int *shape
int n, Array a, ...)
Error DXQueryArrayCommonV(Type *type, Category *category, int *rank, int *shape
int n, Array *alist)

Functional Details

All Arrays a or alist are converted to a common type, category, rank, and shape if a common conversion exists. Both routines set *type, *category, *rank, and *shape to the new converted values if the pointers to these parameters are not NULL.

Arrays with items that have one or more dimensions of shape = 1 are reduced in that dimension to a smaller rank. For example, an array of 1 × n matrices, rank = 2, shape = [1,n], is reduced to an Array of vectors rank = 1, shape = [n]. This rank and shape are then used for comparison.

Note:

This reduction is always performed. The resulting rank may be less than the rank of all Arrays given. (A single 1 × n matrix results in a rank of 1.) Table 6 and Table 7 summarize the conversions allowed between types and between categories.

The resulting rank and shape are the reduced versions created as previously described. The resulting type is the simplest type that is sufficient for all Arrays. The resulting category is the simplest category that is sufficient for all Arrays.

The shape Array must be preallocated with sufficient memory to store the returned rank integers. This will not exceed the maximum rank of the given arrays.

Table 6. Summary of Type Conversions

	Byte	Unsigned Byte	Short	Unsigned Short	Int	Unsigned Int	Float	Double
Byte	A	CNS	A	CNS	A	CNS	A	A
Unsigned Byte	CNS	A	A	A	A	A	A	A
Short	CNS	CNS	A	CNS	A	CNS	A	A
Unsigned Short	CNS	CNS	CNS	A	A	A	A	A
Int	CNS	CNS	CNS	CNS	A	CNS	A	A
Unsigned Int	CNS	CNS	CNS	CNS	CNS	A	A	A
Float	CNS	CNS	CNS	CNS	CNS	CNS	A	A
Double	CNS	CNS	CNS	CNS	CNS	CNS	CNS	A
Notes: CNS = Conversion not supported A = ANSI 'C' type conversion-semantics

Table 7. Summary of Category Conversions

	Real	Complex
Real	Conversion	Conversion
Complex	CNS	Conversion
Notes: CNS = Conversion not supported Real->Complex: a -> a + 0i

Return Value

Return OK and sets the non-NULL parameters; otherwise, returns ERROR and sets an error code.

See Also

DXArrayConvert, DXArrayConvertV, DXExtractFloat, DXExtractInteger, DXExtractNthString, DXExtractParameter, DXExtractString, DXQueryArrayConvert, DXQueryArrayConvertV, DXQueryParameter

12.8 , "Extracting Module Parameters".

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