v?arg

Compute the argument of the input complex number, that is, the arctangent value of the ratio of the imaginary part to the real part.

Interface Definition

C interface:

void vcarg(const int len, const float complex* src, float* dst);

void vzarg(const int len, const double complex* src, double* dst);

Parameters

Parameter	Type	Description	Input/Output
len	Integer	Number of elements in the input vector. If len ≤ 0, the system displays a message indicating that the value of len is invalid.	Input
src	Single-precision floating-point complex type for vcarg Double-precision floating-point complex type for vzarg	Input vector src with length len. If the pointer is null, the system prompts a null pointer error.	Input
dst	Single-precision floating-point type for vcarg Double-precision floating-point type for vzarg	Output vector dst with length len. If the pointer is null, the system prompts a null pointer error.	Output

Parameter

Type

Description

Input/Output

len

Integer

Number of elements in the input vector.

If len ≤ 0, the system displays a message indicating that the value of len is invalid.

Input

src

Single-precision floating-point complex type for vcarg
Double-precision floating-point complex type for vzarg

Input vector src with length len.

If the pointer is null, the system prompts a null pointer error.

Input

dst

Single-precision floating-point type for vcarg
Double-precision floating-point type for vzarg

Output vector dst with length len.

If the pointer is null, the system prompts a null pointer error.

Output

Return Value

The argument of the input complex number is returned for each operation value. The formula is: arg(x + yi) = arctan(y/x)
For special values, see the following table.

RE(z) i * IM(z)	-∞	-X	-0	+0	+X	+∞	NAN
+i * ∞	+∞+i*∞	+π/2	+π/2	+π/2	+π/2	+π/4	NAN
+i * Y	+π		+π/2	+π/2		+0	NAN
+i * 0	+π	+π	+π	+0	+0	+0	NAN
-i * 0	-π	-π	-π	-0	-0	-0	NAN
-i * Y	-π		-π/2	-π/2		-0	NAN
-i * ∞	-3*π/4	-π/2	-π/2	-π/2	-π/2	-π/4	NAN
+i * NAN	NAN	NAN	NAN	NAN	NAN	NAN	NAN

Dependency

C: "kvml.h"

Example

C interface:

    #define N 4
    const complex float src[N] = {
        __builtin_complex(-8.0f, 25.0f),
        __builtin_complex(+INFINITY, -2.1f),
        __builtin_complex(2.6f, 25.0f),
        __builtin_complex(-0.0f, +0.1f)
    };
    float dst[N] = {0};

    vcarg(N, src, dst);
    printFArr("output:", N, dst);
 
    /** 
     *  input: (-8.000,25.000) (  inf,-2.100) (2.600,25.000) (-0.000,0.100)
     *  output: 1.880   -0.000    1.467    1.571
     */

Parent topic: Function Syntax