CMSIS-DSP  
CMSIS DSP Software Library
Functions
Square Root
Fast Math Functions

Functions

arm_status arm_sqrt_f32 (const float32_t in, float32_t *pOut)
 Floating-point square root function. More...
 
arm_status arm_sqrt_q31 (q31_t in, q31_t *pOut)
 Q31 square root function. More...
 
arm_status arm_sqrt_q15 (q15_t in, q15_t *pOut)
 Q15 square root function. More...
 
arm_status arm_sqrt_f16 (float16_t in, float16_t *pOut)
 Floating-point square root function. More...
 

Description

Computes the square root of a number. There are separate functions for Q15, Q31, and floating-point data types. The square root function is computed using the Newton-Raphson algorithm. This is an iterative algorithm of the form: 

     x1 = x0 - f(x0)/f'(x0)

where x1 is the current estimate, x0 is the previous estimate, and f'(x0) is the derivative of f() evaluated at x0. For the square root function, the algorithm reduces to: 

    x0 = in/2                         [initial guess]
    x1 = 1/2 * ( x0 + in / x0)        [each iteration]

Function Documentation

◆ arm_sqrt_f16()

arm_status arm_sqrt_f16 ( float16_t  in,
float16_t *  pOut 
)
Parameters
[in]ininput value
[out]pOutsquare root of input value
Returns
execution status

◆ arm_sqrt_f32()

arm_status arm_sqrt_f32 ( const float32_t  in,
float32_t *  pOut 
)
Parameters
[in]ininput value
[out]pOutsquare root of input value
Returns
execution status

◆ arm_sqrt_q15()

arm_status arm_sqrt_q15 ( q15_t  in,
q15_t *  pOut 
)
Parameters
[in]ininput value. The range of the input value is [0 +1) or 0x0000 to 0x7FFF
[out]pOutpoints to square root of input value
Returns
execution status

◆ arm_sqrt_q31()

arm_status arm_sqrt_q31 ( q31_t  in,
q31_t *  pOut 
)
Parameters
[in]ininput value. The range of the input value is [0 +1) or 0x00000000 to 0x7FFFFFFF
[out]pOutpoints to square root of input value
Returns
execution status