v?expint1

Compute the exponential integral of the input vector.

Interface Definition

C interface:

void vsexpint1(const int len, const float* src, float* dst);

void vdexpint1(const int len, const double* src, double* dst);

Parameters

Parameter	Type	Description	Input/Output
len	Integer	Number of elements in the input vector. If len ≤ 0, an invalid parameter error is reported and the function returns.	Input
src	Single-precision floating-point type for vsexpint1 Double-precision floating-point type for vdexpint1	Input vector src with length len. If the pointer is null, a null pointer error is reported and the function returns.	Input
dst	Single-precision floating-point type for vsexpint1 Double-precision floating-point type for vdexpint1	Output vector dst with length len. If the pointer is null, a null pointer error is reported and the function returns.	Output

Parameter

Type

Description

Input/Output

len

Integer

Number of elements in the input vector.

If len ≤ 0, an invalid parameter error is reported and the function returns.

Input

src

Single-precision floating-point type for vsexpint1
Double-precision floating-point type for vdexpint1

Input vector src with length len.

If the pointer is null, a null pointer error is reported and the function returns.

Input

dst

Single-precision floating-point type for vsexpint1
Double-precision floating-point type for vdexpint1

Output vector dst with length len.

If the pointer is null, a null pointer error is reported and the function returns.

Output

Return Value

Each operation value returns the exponential integral of x.
For special values, see the following table.
Input Value (src)

Output Value (dst)

±0

inf

≥ 0x1p13

+0

<0

nan

nan

nan

Input Value (src)	Output Value (dst)
±0	inf
≥ 0x1p13	+0
<0	nan
nan	nan

Dependencies

C: "kvml.h"

Examples

C interface:

    int i, len = 11; 
    float src[11] = {-100.0f, -1.0f, -0.0f, 0.0f, 0.3f, 0.5f, 1.0f, 100.0f, -INFINITY, INFINITY, NAN}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0;
    }
    vsexpint1(len, src, dst);

    /** 
     *  Output dst: 
     *     nan nan inf inf 0.905677 0.559774 0.219384 0.000000 nan 0.000000 nan
     */

Parent topic: Function Syntax